Sarcomas

Definition

A sarcoma is a malignant tumor (neoplasm), or cancer. Certain sarcomas characteristically spread throughout the body. The word "sarcoma" has its origin in a Greek word whose definition is "fleshy." Tumors come from the mesenchymal tissue, from which connective tissues, blood, lymphatics, bone, and cartilage come. The blood carries sarcomas throughout the body into neighboring tissue, or via the bloodstream. Frequent sites of extension of the tumors are the lung, the liver, and the brain.

Description

When the original site of the cancer is the bone, there is a primary bone cancer. The tumor originates in or near a bone. Most primary bone tumors are benign, and the cells that compose them do not metastasize (spread) to nearby tissue or to other parts of the body.

Sarcomas account for fewer than 1% of all cancers diagnosed in the United States. They can infiltrate nearby tissues, enter the bloodstream, and metastasize to other bones, tissues, and organs far from the site of the original malignancy. Malignant primary bone tumors are characterized as either:

• cancers that originate in the hard material of the bone
• soft-tissue sarcomas that begin in blood vessels, nerves, or tissues containing muscles, fat, or fiber

Types of bone tumors

Osteogenic sarcoma, or osteosarcoma, is the most common form of primary bone cancer, accounting for about 5% of all cancers in children. Every year, 900 new cases of osteosarcoma are diagnosed in the United States. The disease usually affects teenagers and young adults, and is almost twice as common in males as in females.

Osteosarcomas grow very rapidly. Although they can develop in any bone, but they are most often seen along the edge or on the end of one of the fast-growing long bones that support the arms and legs. Approximately 80% of all osteosarcomas develop in the distal femur or in the proximal tibia (parts of the upper and lower leg nearest the knee). The next likely location for an osteosarcoma is the proximal humerus (the bone of the upper arm closest to the shoulder).

Ewing's sarcoma is the second most common form of childhood bone cancer. Accounting for less than 5% of bone tumors in children, Ewing's sarcoma usually begins in the soft tissue or nerves. It rapidly metastasizes to the lungs, and may metastasize to bones in other parts of the body.

Ewing's sarcoma occurs most frequently in children aged 11 to 15. It is more often diagnosed in taller teens. Slightly more males than females develop common bone cancer—but this type is the most frequently found carcinoma in children. The disease is rarely diagnosed in children younger than five and adults older than 30. It primarily affects Caucasians, and rarely occurs in African Americans and native Chinese persons.

Chondrosarcomas are cancerous bone tumors that most often appear in middle age. Usually originating in cartilage in ribs, leg, or hip bones, chondrosarcomas grow slowly. They rarely metastasize to the lungs. It takes years for a chondrosarcoma to metastasize to other parts of the body, and some of these tumors never spread.

Parosteal osteogenic sarcomas, fibrosarcomas, and chordomas are rare. Parosteal osteosarcomas generally involve both the bone and the periosteum, the membrane that covers bones. Fibrosarcomas originate in the ends of the bones in the arm or leg, and then spread to soft tissue. Chordomas develop on the skull or spinal cord.

Osteochondromas, which usually develop between persons aged 10-20 years, are the most common noncancerous primary bone tumors. Giant cell tumors generally develop in a section of the femur near the knee. Giant cell tumors are originally benign, but sometimes become malignant.

Causes and symptoms

The cause of bone cancer is unknown, but the tendency to develop it may be inherited. Children who develop bone tumors are often tall for their age, and the disease seems to be associated with growth spurts during childhood and adolescence. Injuries can make the presence of tumors more apparent, but do not cause them.

A bone that has been broken or exposed to high doses of radiation that has been used to treat other cancers is more likely than other bones to develop osteosarcoma. It should be noted, however, that the amount of radiation in diagnostic x rays poses little or no danger of bone cancer development. A history of noncancerous bone disease also increases bone cancer risk.

Cancer of the eye (retinoblastoma) is a rare tumor of the eye that develops in the cells of the retina, and occurs mostly in patients under five years of age. It is known to be hereditary—the condition is an autosomal-dominant trait.

Both benign and malignant bone tumors can distort and weaken bone, causing pain, but benign tumors are generally painless and asymptomatic.

Patients may feel a lump or mass, but pain in the affected area is the most common early symptom of bone cancer. Pain is not constant in the initial stages of the disease; it is aggravated by activity and may be worst at night. If the tumor is located on a leg bone, the patient may limp. Swelling and weakness of the limb may not be noticed until weeks after the pain began.

Other symptoms of bone cancer include:

• a bone that breaks with minimal trauma, also known as a pathologic fracture
• difficulty moving the affected part of the body
• fatigue
• fever
• a lump or swelling on the trunk, an arm or leg, or another bone
• persistent, unexplained back pain
• weight loss

Diagnosis

Physical examination and routine x rays may provide enough evidence to diagnose benign bone tumors, but biopsy (removal of tumor tissue for microscopic analysis) is the only definitive way to determine the nature of the tumor.

A needle biopsy involves using a fine, thin needle to remove small bits of tumor, or a thick needle to extract tissue samples from the innermost part (the core) of the growth. An excisional biopsy is the surgical removal of a small, accessible tumor and a margin of surrounding normal tissue. An incisional biopsy is performed on tumors too large or inaccessible to be completely removed. A portion of the tumor is removed by the surgeon performing an incisional biopsy. Performed under local or general anesthesia, biopsy reveals whether a tumor is benign or malignant, and ideally identifies the type of cancer cells the malignant tumor contains.

Primary bone cancer is usually diagnosed about three months after symptoms first appear. Twenty percent of these malignant tumors will have already metastasized to the lungs or to other parts of the body.

Imaging techniques

The following procedures are used, in conjunction with biopsy, to diagnose bone cancer:

• Plain x rays. These x rays usually provide a clear image of osteosarcomas.
• The computerized tomography (CAT) scan, or computed tomographic scanning (CT), is a specialized x ray that uses a rotating beam to obtain detailed information about an abnormality and its physical relationship to other parts of the body.
• A CAT scan can show differentiation between osteosarcomas and other types of bone tumors, reveal if tumor cells have spread to other tissues, and help surgeons decide which portion of a growth is best to biopsy. Since malignant bone tumors frequently metastasize to the lungs, a CAT scan of the chest should also be performed. The CAT scan can provide information about other organs that may have been affected. Chest and abdominal CAT scans are used to determine whether Ewing's sarcoma has spread to the lungs, liver, or lymph nodes.
• Magnetic resonance imaging (MRI) is a specialized scan that relies on radio waves and powerful magnets to reflect energy patterns created by tissue abnormalities and specific diseases. MRI provides more detailed information than a CAT scan about tumors and marrow cavities of the bone, and can sometimes detect clusters of cancerous cells that have separated from the original tumor. This valuable information helps physicians select the best approach for treatment.
• Radionuclide bone scans involve the injection of a small amount of radioactive material into a vein. Primary tumors, or cells that have metastasized, absorb the radioactive material and present as dark spots on the scan.

Cytogenic and molecular genetic studies, which assess the structure and composition of chromosomes and genes, may also be used to diagnose osteosarcoma. These tests sometimes help to determine the most appropriate form of treatment.

Laboratory studies

A complete blood count (CBC) reveals abnormalities in the blood, and may indicate whether bone marrow has been affected. A blood test that measures levels of the enzyme lactate dehydrogenase (LDH), can be used determine the prognosis for the survival of a given patient.

Immunohistochemistry involves adding special antibodies and chemicals, or stains, to tumor samples. This technique effectively helps the pathologist to identify cells that are found in Ewing's sarcoma, but that are not present in other malignant tumors.

Reverse transcription polymerase chain reaction (RTPCR) relies on chemical analysis of RNA (the substance in the body that transmits genetic information) to:

• Evaluate the effectiveness of cancer therapies.
• Identify mutations consistent with the presence of Ewing's sarcoma.
• Reveal cancer that recurs after treatment has been completed.

Staging

Once bone cancer has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor helps the oncologist decide which form of treatment is indicated, and to predict how the condition will probably respond to therapy.

An osteosarcoma may be localized or metastatic. A localized osteosarcoma has not spread beyond the bone where it, originated, or beyond nearby muscles, tendons, and other tissues. Metastatic osteosarcoma has spread to the lungs, to bones not directly connected to the bone, or to other tissues or organs.

Treatment

Since the 1960s, when amputation was the only treatment for bone cancer, chemotherapy and innovative surgical techniques have improved survival with intact limbs. Because osteosarcoma is rare, treatment is most often sought at a cancer center staffed by specialists familiar with the disease. A treatment plan for bone cancer, which is devised after the tumor has been diagnosed and staged, may include:

• Radiation therapy. Radiation therapy is used often to treat Ewing's sarcoma.
• Surgery. Surgery, coordinated with diagnostic biopsy, enhances the probability that limb-salvage surgery can be used to remove the cancer, while preserving nearby blood vessels and bones. A metal rod or bone graft is used to replace the area of bone removed. Subsequent surgery may be needed to repair or replace rods that have become loose or broken. Patients who have undergone limb salvage surgery require intensive rehabilitation. It may take as long as one year for a patient to regain full use of a leg following limb salvage surgery. Some patients who undergo this procedure eventually require amputation.
• Chemotherapy. In addition to surgery, chemotherapy is usually administered to kill cancer cells that have separated from the original tumor and spread to other parts of the body. Although chemotherapy can increase the likelihood of future development of another form of cancer, the American Cancer Society maintains that the benefit of chemotherapeutic bone cancer treatment is much greater than its potential risk.
• Amputation. Amputation may be the only therapeutic option for large tumors involving nerves or blood vessels that have not responded to chemotherapy. MRI scans demonstrate the extent of disease in the limb, providing information about how much of it must be removed. The treatment, surgery, is designed to create a cuff (formed of muscles and skin) around the amputated bone. Following surgery, a prosthetic (artificial) leg is fitted over the cuff. Patients who actively participate in the rehabilitation may be walking independently as soon as three months after the amputation.
• Rotationoplasty. Rotationoplasty, sometimes performed after a leg amputation, involves attaching the lower leg and foot to the femur, so that the ankle replaces the knee. A prosthetic is later added to make the leg as long as it is normally. Prosthetic devices are not used to lengthen limbs that remain functional after amputation to remove osteosarcomas located on the upper arm. When an osteosarcoma develops in the jaw bone, the entire lower jaw is removed. Bones from other parts of the body are later grafted onto remaining bone to create a new jaw.

Follow-up treatments

After a patient completes the final course of chemotherapy, a number of tests—CAT or CT scans, bone scans, x rays, and other diagnostic tests—may be repeated to determine if any traces of tumor remain. If none are found, treatment is discontinued, but patients are advised to see their oncologists and orthopedic surgeons every two or three months for the subsequent year. X rays of the chest and affected bone are taken every four months. An annual echocardiogram is recommended to determine whether there have been any adverse cardiovascular effects of chemotherapy, and CT scans are performed every six months.

Patients who have received treatment for Ewing's sarcoma are examined regularly—at gradually lengthening intervals—after completing therapy. Accurate growth measurements are taken at each visit and blood is drawn to test for side effects of treatment. X rays, CAT or CT scans, bone scans, and/or other imaging studies are generally performed every three months during the first year. If no evidence of tumor growth or recurrence is revealed, these tests are performed less frequently in the following years.

Some benign bone tumors shrink or disappear without treatment. However, regular examinations are recommended to determine whether these tumors have changed in any way.

Alternative treatment

Alternative treatments should never be substituted for conventional anticancer treatments or used without the approval of a physician. Some alternative treatments may be used as adjunctive and supportive therapies during and following conventional treatments.

Many patients find that alternative and complementary therapies help to reduce the stress associated with illness, improve immune function and feel better. While there is no evidence that these therapies specifically combat disease, activities such as biofeedback, relaxation, therapeutic touch, massage therapy, and guided imagery have been reported to enhance well-being.

Some cancer patients find that acupuncture alleviates pain, nausea, and vomiting. It may also be effective in helping to maintain energy and relative wellness during surgery, chemotherapy, and radiation. Massage, reflexology, and relaxation techniques are reported to relieve pain, tension, anxiety, and depression.

Claims of effectiveness in fighting cancer have been made for a variety of herbal medicines. These botanical remedies should only be used when prescribed by a practitioner familiar with cancer treatment.

Prognosis

Benign bone tumors rarely recur, but sarcomas can reappear, even after treatment considered effective in eliminating all the cancerous cells.

Likelihood of long-term survival depends on:

• the type and location of the tumor
• how much the tumor has metastasized, and the organs, bones, or tissues affected

More than 85% of patients survive for more than five years after complete surgical removal of low-grade osteosarcomas (tumors that arise in mature tissue and contain a small number of cancerous cells). About 25-30% of patients diagnosed with high-grade osteosarcomas (tumors that develop in immature tissue and contain a large number of cancer cells) will die of the disease.

Two-thirds of all children diagnosed with Ewing's sarcoma live for more than five years after the disease is detected. The outlook is most favorable for children under age 10, and least favorable in patients whose cancer is not diagnosed until after it has metastasized: fewer than three of every 10 of these patients remain alive five years later. More than 80% of patients whose Ewing's sarcoma is confined to a small area, and surgically removed live for at least five years. Postsurgical radiation and chemotherapy add years to their lives. More than 70% of patients live five years or more with a small Ewing's sarcoma that cannot be removed, but only three out of five patients with large, unremovable tumors survive that long. Patients with tumors that do not respond to treatment and those who suffer recurrences have poor outlooks for long-term survival.

Health care team roles

Like other cancer patients, patients with sarcoma are usually cared for by a multidisciplinary team of health professionals. The patient's family physician or primary care provider collaborates with other physician specialists, such as surgeons and oncologists. Radiologic technicians perform x-ray, CT, and MRI scans; nurses and laboratory technicians may obtain samples of blood, urine and other laboratory tests.

Before and after any surgical procedures, including biopsies, the procedures may be explained by nurses or physicians, who are also called upon to help prepare patients and families. Depending on the tumor location and treatment plan, patients may also benefit from rehabilitation therapy with physical therapists, nutritional counseling from dietitians, and counseling from social workers or other mental health professionals.

Prevention

Since the causes of most sarcomas are not known, there are no formal recommendations about how to prevent their development. Among families with an inherited tendency to develop soft tissue sarcomas, careful monitoring may help to ensure early diagnosis and treatment of the disease.

In 1999 and 2000, there were a number of studies that reported both genetic and biologic factors in sarcomas. The reports generated by these studies provide evidence that more and more sarcomas possess the same chromosome abnormalities. The reports also point to the high complexity of these genetic changes; which further complicate identifying any single abnormality associated with sarcomas. Despite their limitations, continuing studies can yield new, therapeutic treatment modalities. These approaches will be experimental, yet they will facilitate advancement in this arena toward even better disease management.

KEY TERMS

Biofeedback— The technique of making unconscious or involuntary bodily processes (as heartbeat or brain waves) perceptible to the senses in order to manipulate them by conscious mental control.

CAT scan (CT scan)— Computerized axial tomography, or computed tomography, tomographic scanning; a specialized x ray that uses a rotating beam to obtain detailed information about an abnormality and its physical relationship to other parts of the body.

Chondrosarcoma— A malignant tumor derived from cartilage cells or their precursors.

Chordoma— Malignant tumor composed of remnants of the embryonic notochord—a flexible rod of cells that in the embryos of higher vertebrates forms the supporting axis of the body—and is found along the spine, attacking especially the bones at the base of the skull, or near the coccyx.

Echocardiogram (ECHO)— The use of beeps of ultrasonic waves directed through the chest wall to record the position and motion of the heart walls or internal structures of the heart.

Ewing's sarcoma— A tumor that invades the shaft of a long bone and that tends to recur, but metastasizes infrequently.

Fibrosarcoma— A sarcoma of relatively low malignancy, consisting mostly of spindle-shaped cells that generally form collagenous fibers of connective tissue.

Magnetic resonance imaging (MRI)— A specialized scan that uses radio waves and powerful magnets to reflect energy created by abnormal tissue and specific diseases.

Metastasis— Transfer of disease from one organ of the body to another not directly connected with it, as a result of transfer of pathogenic microorganisms or to transfer of cells.

Resources

BOOKS

Campanacci, M. Bone and Soft Tissue Tumors: Clinical Features, Imaging, Pathology, and Treatment. Springer Verlag, 1999.

PERIODICALS

Merimsky, Ofer, Yehuda Kollender, Josephine Issakov, et al. "Multiple Primary Malignancies in Association with Soft Tissue Sarcomas." Cancer 91, no. 7 (April 1, 2001):1363-9.

Skapek S. X., and C. H. Chui. "Cytogenics and the biologic basis of sarcomas." Current Opinions in Oncolology 12 (2000): 315-22.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Road NE, Atlanta, GA 30329. (800) ACS-2345. 〈http://www.cancer.org/main.html〉.

Cancer Care, Inc. 1180 Avenue of the Americas, New York, NY 10036. (800) 813-HOPE. 〈http://www.cancercare.org〉.

National Institutes of Health. National Cancer Institute. 9000 Rockville Pike, Bethesda, MD 20892. (800) 4-CANCER. 〈http://www.cancenet.nci.nih.gov/〉.

OTHER

Bone Tumors. 〈http://housecall.orbisnews.com/databases/ami/convert/001230.html〉. (April 11, 1998).

Ewing's Family of Tumors Cancer Information. 〈http://www.cancer.org/cidSpecificCancers/ewing's〉. (April 6, 1998).

Osteosarcoma Cancer Information. 〈http://www.cancer.org/cidSpecificCancers/osteo/index/html〉. (April 11, 1998).

Sarcomas

Definition

A sarcoma is a bone tumor that contains cancer (malignant) cells. A benign bone tumor is an abnormal growth of noncancerous cells.

Description

A primary bone tumor originates in or near a bone. Most primary bone tumors are benign, and the cells that compose them do not spread (metastasize) to nearby tissue or to other parts of the body.

Malignant primary bone tumors account for fewer than 1% of all cancers diagnosed in the United States. They can infiltrate nearby tissues, enter the bloodstream, and metastasize to bones, tissues, and organs far from the original malignancy. Malignant primary bone tumors are characterized as either:

• bone cancers which originate in the hard material of the bone.
• soft-tissue sarcomas which begin in blood vessels, nerves, or tissues containing muscles, fat, or fiber.

Types of bone tumors

Osteogenic sarcoma, or osteosarcoma, is the most common form of bone cancer, accounts for 6% of all instances of the disease, and for about 5% of all cancers that occur in children. Nine hundred new cases of osteosarcoma are diagnosed in the United States every year. The disease usually affects teenagers, and is almost twice as common in boys as in girls.

Osteosarcomas, which grow very rapidly, can develop in any bone but most often occur along the edge or on the end of one of the fast-growing long bones that support the arms and legs. About 80% of all osteosarcomas develop in the parts of the upper and lower leg nearest the knee (the distal femur or in the proximal tibia). The next likely location for an osteosarcoma is the bone of the upper arm closest to the shoulder (the proximal humerus).

Ewing's sarcoma is the second most common form of childhood bone cancer. Accounting for fewer than 5% of bone tumors in children, Ewing's sarcoma usually begins in the soft tissue (the marrow) inside bones of the leg, hips, ribs, and arms. It rapidly infiltrates the lungs, and may metastasize to bones in other parts of the body.

More than 80% of patients who have Ewing's sarcoma are white, and the disease most frequently affects children between ages 5-9, and young adults between ages 20-30. About 27% of all cases of Ewing's sarcoma occur in children under age 10, and 64% occur in adolescents between ages 10-20.

Chondrosarcomas are cancerous bone tumors that most often appear in middle age. Usually originating in strong connective tissue (cartilage) in ribs or leg or hip bones, chondrosarcomas grow slowly. They rarely spread to the lungs. It takes years for a chondrosarcoma to metastasize to other parts of the body, and some of these tumors never spread.

Parosteal osteogenic sarcomas, fibrosarcomas, and chordomas are rare. Parosteal osteosarcomas generally involve both the bone and the membrane that covers it. Fibrosarcomas originate in the ends of the bones in the arm or leg, and then spread to soft tissue. Chordomas develop on the skull or spinal cord.

Osteochondromas, which usually develop between age 10-20, are the most common noncancerous primary bone tumors. Giant cell tumors generally develop in a section of the thigh bone near the knee. Giant cell tumors are originally benign but sometimes become malignant.

Causes and symptoms

The cause of bone cancer is unknown, but the tendency to develop it may be inherited. Children who have bone tumors are often tall for their age, and the disease seems to be associated with growth spurts that occur during childhood and adolescence. Injuries can make the presence of tumors more apparent but do not cause them.

A bone that has been broken or exposed to high doses of radiation used to treat other cancers is more likely than other bones to develop osteosarcoma. A history of noncancerous bone disease also increases bone-cancer risk.

The amount of radiation in diagnostic x rays poses little or no danger of bone-cancer development, but children who have a family history of the most common childhood cancer of the eye (retinoblastoma ), or who have inherited rare cancer syndromes have a greater-than-average risk of developing bone cancer. Exposure to chemicals found in some paints and dyes can slightly raise the risk.

Both benign and malignant bone tumors can distort and weaken bone and cause pain, but benign tumors are generally painless and asymptomatic.

It is sometimes possible to feel a lump or mass, but pain in the affected area is the most common early symptom of bone cancer. Pain is not constant in the initial stages of the disease, but it is aggravated by activity and may be worse at night. If the tumor is located on a leg bone, the patient may limp. Swelling and weakness of the limb may not be noticed until weeks after the pain began.

Other symptoms of bone cancer include:

• a bone that breaks for no apparent reason
• difficulty moving the affected part of the body
• fatigue
• fever
• a lump on the trunk, an arm or leg, or another bone
• persistent, unexplained back pain
• weight loss

Diagnosis

Physical examination and routine x rays may yield enough evidence to diagnose benign bone tumors, but removal of tumor tissue for microscopic analysis (biopsy) is the only sure way to rule out malignancy.

A needle biopsy involves using a fine, thin needle to remove small bits of tumor, or a thick needle to extract tissue samples from the innermost part (the core) of the growth. An excisional biopsy is the surgical removal of a small, accessible tumor. An incisional biopsy is performed on tumors too large or inaccessible to be completely removed. The surgeon performing an incisional biopsy cuts into the patient's skin and removes a portion of the exposed tumor. Performed under local or general anesthetic, biopsy reveals whether a tumor is benign or malignant and identifies the type of cancer cells the malignant tumor contains.

Bone cancer is usually diagnosed about three months after symptoms first appear, and 20% of malignant tumors have metastasized to the lungs or other parts of the body by that time.

Imaging techniques

The following procedures are used, in conjunction with biopsy, to diagnose bone cancer:

• Bone x rays. These x rays usually provide a clear image of osteosarcomas.
• Computerized axial tomography (CAT scan) is a specialized x ray that uses a rotating beam to obtain detailed information about an abnormality and its physical relationship to other parts of the body. A CAT scan can differentiate between osteosarcomas and other types of bone tumors, illustrate how tumor cells have infiltrated other tissues, and help surgeons decide which portion of a growth would be best to biopsy. Because more than four of every five malignant bone tumors metastasize to the lungs, a CAT scan of the chest is performed to see if these organs have been affected. Chest and abdominal CAT scans are used to determine whether Ewing's sarcoma has spread to the lungs, liver, or lymph nodes.
• Magnetic resonance imaging (MRI) is a specialized scan that relies on radio waves and powerful magnets to reflect energy patterns created by tissue abnormalities and specific diseases. An MRI provides more detailed information than does a CAT scan about tumors and marrow cavities of the bone, and can sometimes detect clusters of cancerous cells that have separated from the original tumor. This valuable information helps surgeons select the most appropriate approach for treatment.
• Radionuclide bone scans. These scans involve injecting a small amount of radioactive material into a vein. Primary tumors or cells that have metastasized absorb the radioactive material and show up as dark spots on the scan.

Cytogenic and molecular genetic studies, which assess the structure and composition of chromosomes and genes, may also be used to diagnose osteosarcoma. These tests can sometimes indicate what form of treatment is most appropriate.

Laboratory studies

A complete blood count (CBC) reveals abnormalities in the blood, and may indicate whether bone marrow has been affected. A blood test that measures levels of the enzyme lactate dehydrogenase (LDH) can predict the likelihood of a specific patient's survival.

Immunohistochemistry involves adding special antibodies and chemicals, or stains, to tumor samples. This technique is effective in identifying cells that are found in Ewing's sarcoma but are not present in other malignant tumors.

Reverse transcription polymerase chain reaction (RTPCR) relies on chemical analysis of the substance in the body that transmits genetic information (RNA) to:

• evaluate the effectiveness of cancer therapies
• identify mutations consistent with the presence of Ewing's sarcoma
• reveal cancer that recurs after treatment has been completed

Staging

Once bone cancer has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and predicts how the condition will probably respond to therapy.

An osteosarcoma may be localized or metastatic. A localized osteosarcoma has not spread beyond the bone where it arose or beyond nearby muscles, tendons, and other tissues. A metastatic osteosarcoma has spread to the lungs, to bones not directly connected to the bone in which the tumor originated, or to other tissues or organs.

Treatment

Since the 1960s, when amputation was the only treatment for bone cancer, new chemotherapy drugs and innovative surgical techniques have improved survival with intact limbs. Because osteosarcoma is so rare, patients should consider undergoing treatment at a major cancer center staffed by specialists familiar with the disease.

A treatment plan for bone cancer, developed after the tumor has been diagnosed and staged, may include:

• Amputation. Amputation may be the only therapeutic option for large tumors involving nerves or blood vessels that have not responded to chemotherapy. MRI scans indicate how much of the diseased limb must be removed, and surgery is planned to create a cuff, formed of muscles and skin, around the amputated bone. Following surgery, an artificial(prosthetic) leg is fitted over the cuff. A patient who actively participates in the rehabilitation process may be walking independently as soon as three months after the amputation.
• Chemotherapy. Chemotherapy is usually administered in addition to surgery, to kill cancer cells that have separated from the original tumor and spread to other parts of the body. Although chemotherapy can increase the likelihood of later development of another form of cancer, the American Cancer Society maintains that the need for chemotherapeutic bone-cancer treatment is much greater than the potential risk.
• Surgery. Surgery, coordinated with diagnostic biopsy, enhances the probability that limb-salvage surgery can be used to remove the cancer while preserving nearby blood vessels and bones. A metal rod or bone graft is used to replace the area of bone removed, and subsequent surgery may be needed to repair or replace rods that have loosened or broken. Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery, and patients who have this operation may eventually have to undergo amputation.
• Radiation therapy. Radiation therapy is used often to treat Ewing's sarcoma.
• Rotationoplasty. Rotationoplasty, sometimes performed after a leg amputation, involves attaching the lower leg and foot to the thigh bone, so that the ankle replaces the knee. A prosthetic is later added to make the leg as long as it should be. Prosthetic devices are not used to lengthen limbs that remain functional after amputation to remove osteosarcomas located on the upper arm. When an osteosarcoma develops in the jaw bone, the entire lower jaw is removed. Bones from other parts of the body are later grafted on remaining bone to create a new jaw.

Follow-up treatments

After a patient completes the final course of chemotherapy, CAT scans, bone scans, x rays, and other diagnostic tests may be repeated to determine if any traces of tumor remain. If none are found, treatment is discontinued, but patients are advised to see their oncologist and orthopedic surgeon every two or three months for the next year. X rays of the chest and affected bone are taken every four months. An annual echocardiogram is recommended to evaluate any adverse effect chemotherapy may have had on the heart, and CT scans are performed every six months.

Patients who have received treatment for Ewing's sarcoma are examined often—at gradually lengthening intervals—after completing therapy. Accurate growth measurements are taken during each visit and blood is drawn to be tested for side effects of treatment. X rays, CT scans, bone scans, and other imaging studies are generally performed every three months during the first year. If no evidence of tumor growth or recurrence is indicated, these tests are performed less frequently in the following years.

Some benign bone tumors shrink or disappear without treatment. However, regular examinations are recommended to determine whether these tumors have changed in any way.

Alternative treatment

Alternative treatments should never be substituted for conventional bone-cancer treatments or used without the approval of a physician. However, some alternative treatments can be used as adjunctive and supportive therapies during and following conventional treatments.

Dietary adjustments can be very helpful for patients with cancer. Whole foods, including grains, beans, fresh fruits and vegetables, and high quality fats, should be emphasized in the diet, while processed foods should be avoided. Increased consumption of fish, especially cold water fish like salmon, mackerel, halibut, and tuna, provides a good source of omega-3 fatty acids. Nutritional supplements can build strength and help maintain it during and following chemotherapy, radiation, or surgery. These supplements should be individually prescribed by an alternative practitioner who has experience working with cancer patients.

Many cancer patients claim that acupuncture alleviates pain, nausea, and vomiting. It can also be effective in helping to maintain energy and relative wellness during surgery, chemotherapy, and radiation. Massage, reflexology, and relaxation techniques are said to relieve pain, tension, anxiety, and depression. Exercise can be an effective means of reducing mental and emotional stress, while increasing physical strength. Guided imagery, biofeedback, hypnosis, body work, and progressive relaxation can also enhance quality of life.

Claims of effectiveness in fighting cancer have been made for a variety of herbal medicines. These botanical remedies work on an individual basis and should only be used when prescribed by a practitioner familiar with cancer treatment.

Treating cancer is a complex and individual task. It should be undertaken by a team of support practitioners with varying specialities who can work together for healing the person with cancer.

Prognosis

Benign brain tumors rarely recur, but sarcomas can reappear after treatment was believed to have eliminated every cell.

Likelihood of long-term survival depends on:

• the type and location of the tumor
• how much the tumor has metastasized, and on what organs, bones, or tissues have been affected

More than 85% of patients survive for more than five years after complete surgical removal of low-grade osteosarcomas (tumors that arise in mature tissue and contain a small number of cancerous cells). About 25-30% of patients diagnosed with high-grade osteosarcomas (tumors that develop in immature tissue and contain a large number of cancer cells) will die of the disease.

Two-thirds of all children diagnosed with Ewing's sarcoma will live for more than five years after the disease is detected. The outlook is most favorable for children under age 10, and least favorable in patients whose cancer is not diagnosed until after it has metastasized: fewer than three of every 10 of these patients remain alive five years later. More than 80% of patients whose Ewing's sarcoma is confined to a small area and surgically removed live, for at least five years. Postsurgical radiation and chemotherapy add years to their lives. More than 70% of patients live five years or more with a small Ewing's sarcoma that cannot be removed, but only three out of five patients with large, unremovable tumors survive that long.

Prevention

There is no known way to prevent bone cancer.

Resources

ORGANIZATIONS

American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329-4251. (800) 227-2345. 〈http://www.cancer.org〉.

CancerCare, Inc. 1180 Avenue of the Americas, New York, NY 10036. (800) 813-4673. 〈http://www.cancercare.org〉.

National Cancer Institute. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. (800) 422-6237. 〈http://www.nci.nih.gov〉.

Sarcomas

Definition

A sarcoma is a cancerous (malignant) bone tumor.

Description

A primary bone tumor originates in or near a bone. Most primary bone tumors are benign, and the cells that compose them do not spread (metastasize) to nearby tissue or to other parts of the body.

A sarcoma is a type of malignant primary bone tumor. Malignant primary bone tumors account for less than 1 percent of all cancers diagnosed in the United States. They can infiltrate nearby tissues, enter the bloodstream, and metastasize to bones, tissues, and organs far from the original malignancy. Malignant primary bone tumors are characterized as either bone cancers which originate in the hard material of the bone or soft-tissue sarcomas which begin in blood vessels, nerves, or tissues containing muscles, fat, or fiber.

Types of bone tumors

Osteogenic sarcoma, or osteosarcoma, is the most common form of bone cancer , accounts for 6 percent of all instances of the disease, and for about 5 percent of all cancers that occur in children. Nine hundred new cases of osteosarcoma are diagnosed in the United States every year. The disease usually affects teenagers and is almost twice as common in boys as in girls.

Osteosarcomas, which grow very rapidly, can develop in any bone but most often occur along the edge or on the end of one of the fast-growing long bones that support the arms and legs. About 80 percent of all osteosarcomas develop in the parts of the upper and lower leg nearest the knee (the distal femur or in the proximal tibia). The next likely location for an osteosarcoma is the bone of the upper arm closest to the shoulder (the proximal humerus).

Ewing's sarcoma is the second most common form of childhood bone cancer. Accounting for fewer than 5 percent of bone tumors in children, Ewing's sarcoma usually begins in the soft tissue (the marrow) inside bones of the leg, hips, ribs, and arms. It rapidly infiltrates the lungs and may metastasize to bones in other parts of the body.

More than 80 percent of patients who have Ewing's sarcoma are white, and the disease most frequently affects children between the ages five and nine and young adults between ages 20 and 30. About 27 percent of all cases of Ewing's sarcoma occur in children under the age of ten, and 64 percent occur in adolescents between the ages of ten and 20.

Chondrosarcomas are cancerous bone tumors that most often appear in middle age. Usually originating in strong connective tissue (cartilage) in ribs or leg or hip bones, chondrosarcomas grow slowly. They rarely spread to the lungs. It takes years for a chondrosarcoma to metastasize to other parts of the body, and some of these tumors never spread.

Parosteal osteogenic sarcomas, fibrosarcomas, and chordomas are rare. Parosteal osteosarcomas generally involve both the bone and the membrane that covers it. Fibrosarcomas originate in the ends of the bones in the arm or leg and then spread to soft tissue. Chordomas develop on the skull or spinal cord.

Osteochondromas, which usually develop between the ages of ten and 20, are the most common noncancerous primary bone tumors. Giant cell tumors generally develop in a section of the thigh bone near the knee. Giant cell tumors are originally benign but sometimes become malignant.

Causes and symptoms

The cause of bone cancer is unknown, but the tendency to develop it may be inherited. Children who have bone tumors are often tall for their age, and the disease seems to be associated with growth spurts that occur during childhood and adolescence . Injuries can make the presence of tumors more apparent but do not cause them.

A bone that has been broken or exposed to high doses of radiation used to treat other cancers is more likely than other bones to develop osteosarcoma. A history of noncancerous bone disease also increases bone-cancer risk.

The amount of radiation in diagnostic x rays poses little or no danger of bone-cancer development, but children who have a family history of the most common childhood cancer of the eye (retinoblastoma ) or who have inherited rare cancer syndromes have a greater-than-average risk of developing bone cancer. Exposure to chemicals found in some paints and dyes can slightly raise the risk.

Both benign and malignant bone tumors can distort and weaken bone and cause pain , but benign tumors are generally painless and asymptomatic.

It is sometimes possible to feel a lump or mass, but pain in the affected area is the most common early symptom of bone cancer. Pain is not constant in the initial stages of the disease, but it is aggravated by activity and may be worse at night. If the tumor is located on a leg bone, the patient may limp. Swelling and weakness of the limb may not be noticed until weeks after the pain begins.

Other symptoms of bone cancer include:

• a bone that breaks for no apparent reason
• difficulty moving the affected part of the body
• fatigue
• fever
• a lump on the trunk, an arm or leg, or another bone
• persistent, unexplained back pain
• weight loss

Diagnosis

Physical examination and routine x rays may yield enough evidence to diagnose benign bone tumors, but removal of tumor tissue for microscopic analysis (biopsy) is the only sure way to rule out malignancy.

A needle biopsy involves using a fine, thin needle to remove small bits of tumor, or a thick needle to extract tissue samples from the innermost part (the core) of the growth. An excisional biopsy is the surgical removal of a small, accessible tumor. An incisional biopsy is performed on tumors too large or inaccessible to be completely removed. The surgeon performing an incisional biopsy cuts into the patient's skin and removes a portion of the exposed tumor. Performed under local or general anesthetic, biopsy reveals whether a tumor is benign or malignant and identifies the type of cancer cells the malignant tumor contains.

Bone cancer is usually diagnosed about three months after symptoms first appear, and 20 percent of malignant tumors have metastasized to the lungs or other parts of the body by that time.

Imaging techniques

The following procedures are used, in conjunction with biopsy, to diagnose bone cancer:

• Bone x rays usually provide a clear image of osteosarcomas.
• Computerized axial tomography (CAT scan), a specialized x ray that uses a rotating beam to obtain detailed information about an abnormality and its physical relationship to other parts of the body, can differentiate between osteosarcomas and other types of bone tumors, illustrate how tumor cells have infiltrated other tissues, and help surgeons decide which portion of a growth would be best to biopsy. Because more than four of every five malignant bone tumors metastasize to the lungs, a CAT scan of the chest is performed to see if these organs have been affected. Chest and abdominal CAT scans are used to determine whether Ewing's sarcoma has spread to the lungs, liver, or lymph nodes.
• Magnetic resonance imaging (MRI), a specialized scan that relies on radio waves and powerful magnets to reflect energy patterns created by tissue abnormalities and specific diseases, provides more detailed information than does a CAT scan about tumors and marrow cavities of the bone and can sometimes detect clusters of cancerous cells that have separated from the original tumor. This valuable information helps surgeons select the most appropriate approach for treatment.
• Radionuclide bone scans involve injecting a small amount of radioactive material into a vein. Primary tumors or cells that have metastasized absorb the radioactive material and show up as dark spots on the scan.

Cytogenic and molecular genetic studies, which assess the structure and composition of chromosomes and genes, may also be used to diagnose osteosarcoma. These tests can sometimes indicate what form of treatment is most appropriate.

Laboratory studies

A complete blood count (CBC) reveals abnormalities in the blood and may indicate whether bone marrow has been affected. A blood test that measures levels of the enzyme lactate dehydrogenase (LDH) can help predict the likelihood of a specific patient's survival.

Immunohistochemistry involves adding special antibodies and chemicals or stains to tumor samples. This technique is effective in identifying cells that are found in Ewing's sarcoma but are not present in other malignant tumors.

Reverse transcription polymerase chain reaction (RTPCR) relies on chemical analysis of the substance in the body that transmits genetic information (RNA) to evaluate the effectiveness of cancer therapies, identify mutations consistent with the presence of Ewing's sarcoma, and reveal cancer that recurs after treatment has been completed.

Staging

Once bone cancer has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate and predicts how the condition will probably respond to therapy.

An osteosarcoma may be localized or metastatic. A localized osteosarcoma has not spread beyond the bone where it arose or beyond nearby muscles, tendons, and other tissues. A metastatic osteosarcoma has spread to the lungs, to bones not directly connected to the bone in which the tumor originated, or to other tissues or organs.

Treatment

In the 1960s, amputation was the only treatment for bone cancer. Between then and the early 2000s chemotherapy drugs and innovative surgical techniques improved survival with intact limbs. Because osteosarcoma is so rare, patients should consider undergoing treatment at a major cancer center staffed by specialists familiar with the disease.

A treatment plan for bone cancer, developed after the tumor has been diagnosed and staged, may include the following:

• Amputation may be the only therapeutic option for large tumors involving nerves or blood vessels that have not responded to chemotherapy. MRI scans indicate how much of the diseased limb must be removed, and surgery is planned to create a cuff, formed of muscles and skin, around the amputated bone. Following surgery, an artificial (prosthetic) leg is fitted over the cuff. A patient who actively participates in the rehabilitation process may be walking independently as soon as three months after the amputation.
• Chemotherapy is usually administered in addition to surgery, to kill cancer cells that have separated from the original tumor and spread to other parts of the body. Although chemotherapy can increase the likelihood of later development of another form of cancer, the American Cancer Society maintains that the need for chemotherapeutic bone-cancer treatment is much greater than the potential risk.
• Surgery, coordinated with diagnostic biopsy, enhances the probability that limb-salvage surgery can be used to remove the cancer while preserving nearby blood vessels and bones. A metal rod or bone graft is used to replace the area of bone removed, and subsequent surgery may be needed to repair or replace rods that become loose or break. Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery, and patients who have this operation may eventually have to undergo amputation.
• Radiation therapy is used often to treat Ewing's sarcoma.
• Rotationoplasty, sometimes performed after a leg amputation, involves attaching the lower leg and foot to the thigh bone, so that the ankle replaces the knee. A prosthetic is later added to make the leg as long as it should be. Prosthetic devices are not used to lengthen limbs that remain functional after amputation to remove osteosarcomas located on the upper arm. When an osteosarcoma develops in the jawbone, the entire lower jaw is removed. Bones from other parts of the body are later grafted on remaining bone to create a new jaw.

Follow-up treatments

After a patient completes the final course of chemotherapy, CAT scans, bone scans, x rays, and other diagnostic tests may be repeated to determine if any traces of tumor remain. If none is found, treatment is discontinued, but patients are advised to see their oncologist and orthopedic surgeon every two or three months for the following year. X rays of the chest and affected bone are taken every four months. An annual echocardiogram is recommended to evaluate any adverse effect chemotherapy may have had on the heart, and CT scans are performed every six months.

Patients who have received treatment for Ewing's sarcoma are examined often—at gradually lengthening intervals—after completing therapy. Accurate growth measurements are taken during each visit and blood is drawn to be tested for side effects of treatment. X rays, CT scans, bone scans, and other imaging studies are generally performed every three months during the first year. If no evidence of tumor growth or recurrence is indicated, these tests are performed less frequently in the following years.

Some benign bone tumors shrink or disappear without treatment. However, regular examinations are recommended to determine whether these tumors have changed in any way.

Prognosis

Benign brain tumors rarely recur, but sarcomas can reappear after treatment was believed to have eliminated every cell.

Likelihood of long-term survival depends on the type and location of the tumor, how much the tumor has metastasized, and on what organs, bones, or tissues have been affected.

More than 85 percent of patients survive for more than five years after complete surgical removal of low-grade osteosarcomas (tumors that arise in mature tissue and contain a small number of cancerous cells). About 25 to 30 percent of patients diagnosed with high-grade osteosarcomas (tumors that develop in immature tissue and contain a large number of cancer cells) die of the disease.

Two-thirds of all children diagnosed with Ewing's sarcoma live for more than five years after the disease is detected. The outlook is most favorable for children under the age of ten, and least favorable in patients whose cancer is not diagnosed until after it has metastasized: fewer than three of every ten of these patients remain alive five years later. More than 80 percent of patients whose Ewing's sarcoma is confined to a small area and surgically removed live, for at least five years. Postsurgical radiation and chemotherapy add years to their lives. More than 70 percent of patients live five years or more with a small Ewing's sarcoma that cannot be removed, but only three out of five patients with large, unremovable tumors survive that long.

Prevention

There is no known way to prevent bone cancer.

Parental concerns

Careful attention to a child's diet can be very helpful for patients with cancer. This can be difficult when the cancer and/or the treatments are affecting the appetite, however. Whole foods, including grains, beans, fresh fruits and vegetables, and high quality fats, should be emphasized in the diet, while processed foods should be avoided. Increased consumption of fish, especially coldwater fish such as salmon, mackerel, halibut, and tuna, provides a good source of omega-3 fatty acids. Nutritional supplements can build strength and help maintain it during and following chemotherapy, radiation, or surgery.

Guided imagery and relaxation techniques can be helpful for children undergoing difficult treatments. Support groups for the child and the family can be very helpful and can give provide an important emotional outlet for the child, the parents, and the siblings.

Resources

BOOKS

Brennan, Murray F., et al. Diagnosis and Management of Sarcoma. Oxford, UK: Isis Medical Media Limited, 2002.

Ewing's Sarcoma: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, CA: Icon Group International, 2004.

ORGANIZATIONS

American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329–4251. Web site: <www.cancer.org>.

CancerCare Inc. 1180 Avenue of the Americas, New York, NY 10036. Web site: <www.cancercare.org>.

National Cancer Institute. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892–2580. Web site: <www.nci.nih.gov>.

WEB SITES

"Ewing's Sarcoma." Children's Cancer Web, January 11, 2003. Available online at <www.cancerindex.org/ccw/guide2e.htm> (accessed December 30, 2004).

Maureen Haggerty Rosalyn Carson-DeWitt, MD

Sarcomas

Definition

Most primary bone tumors are called sarcomas. A sarcoma is a bone tumor that contains cancer (malignant) cells. Sarcomas can also affect muscle, tendons, ligaments, and other tissues in the body. A benign bone tumor is an abnormal growth of noncancerous cells. Sometimes other cancer types (advanced breast cancer , prostate cancer , and lung cancer ) will spread to the bone. This is known as metastatic bone cancer. Sometimes other types of cancers, such as multiple myeloma and some lymphomas and leukemias that start in the bone marrow, are referred to as “bone cancers”. However, these types of cancers are not true bone cancers. The main or true type of primary bone cancer is sarcoma.

Description

A primary bone tumor originates in or near a bone. Most primary bone tumors are benign, and the cells that compose them do not spread (metastasize) to nearby tissue or to other parts of the body.

Malignant primary bone tumors can infiltrate nearby tissues, enter the bloodstream, and metastasize to bones, tissues, and organs far from the original malignancy.

Types of bone tumors

Osteogenic sarcoma, or osteosarcoma, is the most common form of bone cancer, accounts for 6% of all instances of the disease, and for about 5% of all cancers that occur in children. Nine hundred new cases of osteosarcoma are diagnosed in the United States every year. The disease usually affects teenagers, and is almost twice as common in boys as in girls. About 10% of cases of osteosarcoma occur in older adults in their 60s and 70s.

Osteosarcomas, which grow very rapidly, can develop in any bone but most often occur along the edge or on the end of one of the fast-growing long bones that support the arms and legs. About 80% of all osteosarcomas develop in the parts of the upper and lower leg nearest the knee (the distal femur or in the proximal tibia). The next likely location for an osteosarcoma is the bone of the upper arm closest to the shoulder (the proximal humerus).

Ewing's sarcoma is the second most common form of childhood bone cancer. Accounting for fewer than 5% of bone tumors in children, Ewing's sarcoma usually begins in the soft tissue (the marrow) inside bones of the leg, hips, ribs, and arms. It rapidly infiltrates the lungs, and may metastasize to bones in other parts of the body. Ewing's sarcoma is rare in adults over the age of 30.

Chondrosarcomas are cancerous bone tumors that is rarely diagnosed in individuals under the age of 20. The risk of developing this type of bone tumor continues to rise after age 20 until about age 75. It is the second most common type of true bone cancer. Usually originating in strong connective tissue (cartilage) in ribs or leg or hip bones, chondrosarcomas grow slowly. They rarely spread to the lungs. It takes years for a chondrosarcoma to metastasize to other parts of the body, and some of these tumors never spread.

Other types of cancerous bone tumors are fibrosarcomas and malignant fibrous histiocytomas, giant cell tumors of bone, and chordomas. Fibrosarcomas and malignant fibrous histiocytomas, which usually occur in older and middle-age adults, usually start in the soft tissues that surround the bone. The bones of the jaw, arms, and legs are most typically affected. Only about 10% of giant cell bone tumors are malignant tumors. These tumors are most common in young and middle-aged adults and most often appear in the arm or leg bones. Chordomas, which are usually diagnosed in adults over age 30, develop in the base of the skull and bones of the spine. Chordomas tend to grow slowly.

Demographics

Primary bone cancers are relatively rare in the United States and comprise only a very small percentage of all cancers diagnosed in this country

Causes and symptoms

The cause of bone cancer is unknown, but the tendency to develop it may be inherited. Children who have bone tumors are often tall for their age, and the disease seems to be associated with growth spurts that occur during childhood and adolescence. Injuries can make the presence of tumors more apparent but do not cause them.

A bone that has been broken or exposed to high doses of radiation used to treat other cancers is more likely than other bones to develop osteosarcoma. A history of noncancerous bone disease also increases bone-cancer risk.

The amount of radiation in diagnostic x rays poses little or no danger of bone-cancer development, but children who have a family history of the most common childhood cancer of the eye (retinoblastoma), or who have inherited rare cancer syndromes have a greater-than-average risk of developing bone cancer. Exposure to chemicals found in some paints and dyes can slightly raise the risk.

Both benign and malignant bone tumors can distort and weaken bone and cause pain , but benign tumors are generally painless and asymptomatic.

It is sometimes possible to feel a lump or mass, but pain in the affected area is the most common early symptom of bone cancer. Pain is not constant in the initial stages of the disease, but it is aggravated by activity and may be worse at night. If the tumor is located on a leg bone, the patient may limp. Swelling and weakness of the limb may not be noticed until weeks after the pain began.

Other symptoms of bone cancer include:

• a bone that breaks for no apparent reason
• difficulty moving the affected part of the body
• fatigue
• fever
• a lump on the trunk, an arm or leg, or another bone
• persistent, unexplained back pain
• weight loss

Diagnosis

Physical examination and routine x rays may yield enough evidence to diagnose benign bone tumors, but removal of tumor tissue for microscopic analysis (biopsy) is the only sure way to rule out malignancy.

A needle biopsy involves using a fine, thin needle to remove small bits of tumor, or a thick needle to extract tissue samples from the innermost part (the core) of the growth. A surgical bone biopsy may be performed to remove a small portion of a large tumor. The procedure may require general anesthesia

Bone cancer is usually diagnosed about three months after symptoms first appear, and 20% of malignant tumors have metastasized to the lungs or other parts of the body by that time.

Imaging techniques

The following procedures are used, in conjunction with biopsy, to diagnose bone cancer:

• Bone x rays. These x rays usually provide a clear image of osteosarcomas.
• Computerized axial tomography (CAT scan) is a specialized x ray that uses a rotating beam to obtain detailed information about an abnormality and its physical relationship to other parts of the body. A CAT scan can differentiate between osteosarcomas and other types of bone tumors, illustrate how tumor cells have infiltrated other tissues, and help surgeons decide which portion of a growth would be best to biopsy. Because more than four of every five malignant bone tumors metastasize to the lungs, a CAT scan of the chest is performed to see if these organs have been affected. Chest and abdominal CAT scans are used to determine whether Ewing's sarcoma has spread to the lungs, liver, or lymph nodes.
• Magnetic resonance imaging (MRI) is a specialized scan that relies on radio waves and powerful magnets to reflect energy patterns created by tissue abnormalities and specific diseases. An MRI provides more detailed information than does a CAT scan about tumors and marrow cavities of the bone, and can sometimes detect clusters of cancerous cells that have separated from the original tumor. This valuable information helps surgeons select the most appropriate approach for treatment.
• Radionuclide bone scans. These scans involve injecting a small amount of radioactive material into a vein. Primary tumors or cells that have metastasized absorb the radioactive material and show up as dark spots on the scan.

Cytogenic and molecular genetic studies, which assess the structure and composition of chromosomes and genes, may also be used to diagnose osteosarcoma. These tests can sometimes indicate what form of treatment is most appropriate.

Laboratory studies

A complete blood count (CBC) reveals abnormalities in the blood, and may indicate whether bone marrow has been affected. A blood test that measures levels of the enzyme lactate dehydrogenase (LDH) can predict the likelihood of a specific patient's survival.

Immunohistochemistry involves adding special antibodies and chemicals, or stains, to tumor samples. This technique is effective in identifying cells that are found in Ewing's sarcoma but are not present in other malignant tumors.

Reverse transcription polymerase chain reaction (RTPCR) relies on chemical analysis of the substance in the body that transmits genetic information (RNA) to:

• evaluate the effectiveness of cancer therapies
• identify mutations consistent with the presence of Ewing's sarcoma
• reveal cancer that recurs after treatment has been completed

Staging

Once bone cancer has been diagnosed, the tumor is staged. This process indicates how far the tumor has spread from its original location. The stage of a tumor suggests which form of treatment is most appropriate, and predicts how the condition will probably respond to therapy.

An osteosarcoma may be localized or metastatic. A localized osteosarcoma has not spread beyond the bone where it arose or beyond nearby muscles, tendons, and other tissues. A metastatic osteosarcoma has spread to the lungs, to bones not directly connected to the bone in which the tumor originated, or to other tissues or organs.

Treatment

Since the 1960s, when amputation was the only treatment for bone cancer, new chemotherapy drugs and innovative surgical techniques have improved survival with intact limbs. Because osteosarcoma is so rare, patients should consider undergoing treatment at a major cancer center staffed by specialists familiar with the disease.

A treatment plan for bone cancer, developed after the tumor has been diagnosed and staged, may include surgery, chemotherapy, and/or radiation therapy. Chemotherapy is usually administered in addition to surgery to kill cancer cells that have separated from the original tumor and spread to other parts of the body.

Surgery, coordinated with diagnostic biopsy, enhances the probability that limb-salvage surgery can be used to remove the cancer while preserving nearby blood vessels and bones. A metal rod or bone graft is used to replace the area of bone removed, and subsequent surgery may be needed to repair or replace rods that have loosened or broken. Patients who have undergone limb-salvage surgery need intensive rehabilitation. It may take as long as a year for a patient to regain full use of a leg following limb-salvage surgery, and patients who have this operation may eventually have to undergo amputation

Radiation therapy is used often to treat Ewing's sarcoma.

Rotationoplasty, sometimes performed after a leg amputation, involves attaching the lower leg and foot to the thigh bone, so that the ankle replaces the knee. A prosthetic is later added to make the leg as long as it should be. Prosthetic devices are not used to lengthen limbs that remain functional after amputation to remove osteosarcomas located on the upper arm. When an osteosarcoma develops in the jaw bone, the entire lower jaw is removed. Bones from other parts of the body are later grafted on remaining bone to create a new jaw.

Follow-up treatments

After a patient completes the final course of chemotherapy, CAT scans, bone scans, x rays, and other diagnostic tests may be repeated to determine if any traces of tumor remain. If none are found, treatment is discontinued, but patients are advised to see their oncologist and orthopedic surgeon every two or three months for the next year. X rays of the chest and affected bone are taken every four months. An annual echocardiogram is recommended to evaluate any adverse effect chemotherapy may have had on the heart, and CT scans are performed every six months.

Patients who have received treatment for Ewing's sarcoma are examined often—at gradually lengthening intervals—after completing therapy. Accurate growth measurements are taken during each visit and blood is drawn to be tested for side effects of treatment. X rays, CT scans, bone scans, and other imaging studies are generally performed every three months during the first year. If no evidence of tumor growth or recurrence is indicated, these tests are performed less frequently in the following years.

Some benign bone tumors shrink or disappear without treatment. However, regular examinations are recommended to determine whether these tumors have changed in any way.

Alternative treatment

Alternative treatments should never be substituted for conventional bone-cancer treatments or used without the approval of a physician. However, some alternative treatments can be used as adjunctive and supportive therapies during and following conventional treatments.

Nutrition/dietetic concerns

Dietary adjustments can be very helpful for patients with cancer. Whole foods, including grains, beans, fresh fruits and vegetables, and high quality fats, should be emphasized in the diet , while processed foods should be avoided. Increased consumption of fish, especially cold water fish like salmon, mackerel, halibut, and tuna, provides a good source of omega-3 fatty acids. Nutritional supplements can build strength and help maintain it during and following chemotherapy, radiation, or surgery. These supplements should be individually prescribed by an alternative practitioner who has experience working with cancer patients.

Prognosis

Some types of primary bone cancers can reappear after treatment was believed to have eliminated the cancer.

Likelihood of long-term survival depends on:

• the type and location of the tumor
• how much the tumor has metastasized, and on what organs, bones, or tissues have been affected

More than 85% of patients survive for more than five years after complete surgical removal of low-grade osteosarcomas (tumors that arise in mature tissue and contain a small number of cancerous cells). About 25–30% of patients diagnosed with high-grade osteosarcomas (tumors that develop in immature tissue and contain a large number of cancer cells) will die of the disease.

QUESTIONS TO ASK YOUR DOCTOR

• Is my bone cancer a primary bone cancer or a metastatic bone cancer?
• What type of diagnostic tests will I be required to undergo?
• How will my cancer be treated?
• Does my type of bone cancer usually require amputation?
• Will I have to undergo chemotherapy and/or radiation therapy treatments?

Prevention

There is no known way to prevent bone cancer.

Resources

organizations

American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA30329-4251. (800) 227-2345. http://www.cancer.org.

CancerCare, Inc. 1180 Avenue of the Americas, New York, NY 10036. (800) 813-4673. http://www.cancercare.org.

National Cancer Institute. Building 31, Room 10A31, 31 Center Drive, MSC 2580, Bethesda, MD 20892-2580. (800) 422-6237. http://www.nci.nih.gov.

Maureen Haggerty

Melinda Oberleitner R.N., D.N.S.

sarcoma (sar-koh-mă) n. any cancer of connective tissue. These tumours may occur in any part of the body; they arise in fibrous tissue, muscle, fat, bone, cartilage, synovium, blood and lymphatic vessels, and various other tissues. See also chondrosarcoma, fibrosarcoma, leiomyosarcoma, liposarcoma, lymphangiosarcoma, osteosarcoma, rhabdomyosarcoma.
—sarcomatous adj.