Bone cancers

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

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 one percent of all cancers diagnosed in the United States. They can infiltrate nearby tissues, enterthe bloodstream, and metastasize to bones, tissues, and organs far from the original malignancy. Malignant primary bone tumors are characterized as eitherbone cancers that originate in the hard material of the bone or soft-tissuesarcomas that begin in blood vessels, nerves, or tissues containing muscles,fat, or fiber.

Osteogenic sarcoma, or osteosarcoma, is the most common form of bone cancer.It accounts for six percent of all instances of the disease, and for about five percent of all cancers that occur in children. Osteosarcomas can grow veryrapidly. They often occur along the edge or on the end of one of the fast-growing long bones of the arms and legs.

Ewing's sarcoma is the second most common form of childhood bone cancer. It 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.

Chondrosarcomas are cancerous bone tumors that most often appear in middle age. Usually originating in strong connective tissue (cartilage) in ribs, legs,or hip bones, chondrosarcomas grow slowly taking years to spread to other parts of the body.

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

Osteochondromas, which usually develop between age 10-20, are the most commonnoncancerous 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.

The cause of bone cancer is unknown, but the tendency to develop it may be inherited, and the disease seems to be associated with growth spurts that occurduring 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 (and well above the amount involved in x rays) is more likely than other bones to develop osteosarcoma. A history of noncancerous bone disease also increases bone-cancer risk.

Both benign and malignant bone tumors can distort and weaken bone and cause pain, but benign tumors are more likely to be painless. Pain is the most common early symptom of bone cancer. It is not constant in the early stages of thedisease, but it is aggravated by activity and may be worst at night. If thetumor 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.

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

Bone cancer is usually diagnosed about three months after symptoms first appear. Twenty percent of malignant tumors have metastasized to the lungs or other parts of the body by that time. Once bone cancer has been diagnosed, the tumor is staged to indicate 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.

Bone x rays, computerized axial tomography (CAT scan), magnetic resonance imaging (MRI) and radionuclide bone scans are all used to distinguish between the different kinds of benign and malignant bone tumors.

Laboratory tests such as a complete blood count (CBC), immunohistochemistry,and reverse transcription polymerase chain reaction (RTPCR) are used to evaluate the type of tumor and the effectiveness of cancer therapies.

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

A treatment plan for bone cancer may include chemotherapy, surgery, radiationtherapy, amputation, or 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 tomake the leg as long as it should be.

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 anytraces of tumor remain. Patients who have received treatment for Ewing's sarcoma are examined often after completing therapy. Regular examinations are recommended to determine whether these tumors have changed in any way.

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 tissueshave been affected.

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 duringand following conventional treatments.

Dietary adjustments, acupuncture, massage, reflexology, and relaxation techniques are said to relieve pain, tension. Anxiety, and depression. Exercise canbe an effective means of reducing mental and emotional stress, while increasing physical strength. Guided imagery, biofeedback, hypnosis, body work, andprogressive relaxation can also enhance quality of life.

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