Bone cancer

What is bone cancer?

Bone cancer is a malignant (cancerous) tumor of the bone that destroys normal bone tissue. Not all bone tumors are malignant. In fact, benign (noncancerous) bone tumors are more common than malignant ones. Both malignant and benign bone tumors may grow and compress healthy bone tissue, but benign tumors do not spread, do not destroy bone tissue, and are rarely a threat to life.

Malignant tumors that begin in bone tissue are called primary bone cancer. Cancer that metastasizes (spreads) to the bones from other parts of the body, such as the breast, lung, or prostate, is called metastatic cancer, and is named for the organ or tissue in which it began. Primary bone cancer is far less common than cancer that spreads to the bones.

What are the symptoms of bone cancer?

Pain is the most common symptom of bone cancer, but not all bone cancers cause pain. Persistent or unusual pain or swelling in or near a bone can be caused by cancer or by other conditions. It is important to see a doctor to determine the cause.

What are the possible causes of bone cancer?

Bone cancer does not have a clearly defined cause, researchers have identified several factors that increase the likelihood of developing these tumors.

• Osteosarcoma occurs more frequently in people who have had high-dose external radiation therapy or treatment with certain anticancer drugs; children seem to be particularly susceptible.
• A small number of bone cancers are due to heredity. For example, children who have had hereditary retinoblastoma (an uncommon cancer of the eye) are at a higher risk of developing osteosarcoma, particularly if they are treated with radiation.
• People who have hereditary defects of bones and people with metal implants, which doctors sometimes use to repair fractures, are more likely to develop osteosarcoma. Ewing sarcoma is not strongly associated with any heredity cancer syndromes, congenital childhood diseases, or previous radiation exposure

Different types of primary bone cancer

Cancer can begin in any type of bone tissue. Bones are made up of osteoid (hard or compact), cartilaginous (tough, flexible), and fibrous (threadlike) tissue, as well as elements of bone marrow (soft, spongy tissue in the center of most bones).

Common types of primary bone cancer include the following:

Osteosarcoma, which arises from osteoid tissue in the bone. This tumor occurs most often in the knee and upper arm.

Chondrosarcoma, which begins in cartilaginous tissue. Cartilage pads the ends of bones and lines the joints. Chondrosarcoma occurs most often in the pelvis (located between the hip bones), upper leg, and shoulder. Sometimes a chondrosarcoma contains cancerous bone cells. In that case, doctors classify the tumor as an osteosarcoma.

The Ewing Sarcoma Family of Tumors (ESFTs), which usually occur in bone but may also arise in soft tissue (muscle, fat, fibrous tissue, blood vessels, or other supporting tissue). Scientists think that ESFTs arise from elements of primitive nerve tissue in the bone or soft tissue. ESFTs occur most commonly along the backbone and pelvis and in the legs and arms .

How often does bone cancer occur?

Primary bone cancer is rare. It accounts for much less than 1 percent of all cancers. Different types of bone cancer are more likely to occur in certain populations:

• Osteosarcoma occurs most commonly between ages 10 and 19. However, people over age 40 who have other conditions, such as Paget disease (a benign condition characterized by abnormal development of new bone cells), are at increased risk of developing this cancer.
• Chondrosarcoma occurs mainly in older adults (over age 40). The risk increases with advancing age. This disease rarely occurs in children and adolescents.
• ESFTs occur most often in children and adolescents under 19 years of age. Boys are affected more often than girls. These tumors are extremely rare in African American children.

How is bone cancer diagnosed?

To help diagnose bone cancer, the doctor asks about the patient’s personal and family medical history. The doctor also performs a physical examination and may order laboratory and other diagnostic tests. These tests may include the following:

X-rays, which can show the location, size, and shape of a bone tumor. If x-rays suggest that an abnormal area may be cancer, the doctor is likely to recommend special imaging tests. Even if x-rays suggest that an abnormal area is benign, the doctor may want to do further tests, especially if the patient is experiencing unusual or persistent pain.

• A bone scan, which is a test in which a small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it then collects in the bones and is detected by a scanner.
• A computed tomography (CT or CAT) scan, which is a series of detailed pictures of areas inside the body, taken from different angles, that are created by a computer linked to an x-ray machine.
• A magnetic resonance imaging (MRI) procedure, which uses a powerful magnet linked to a computer to create detailed pictures of areas inside the body without using x-rays.
• A positron emission tomography (PET) scan, in which a small amount of radioactive glucose (sugar) is injected into a vein, and a scanner is used to make detailed, computerized pictures of areas inside the body where the glucose is used. Because cancer cells often use more glucose than normal cells, the pictures can be used to find cancer cells in the body.

What are the treatment options for bone cancer?

• Treatment options depend on the type, size, location, and stage of the cancer, as well as the person’s age and general health. Treatment options for bone cancer include surgery, chemotherapy, radiation therapy, and cryosurgery.
• Surgery is the usual treatment for bone cancer. The surgeon removes the entire tumor with negative margins (no cancer cells are found at the edge or border of the tissue removed during surgery). The surgeon may also use special surgical techniques to minimize the amount of healthy tissue removed with the tumor.
• Dramatic improvements in surgical techniques and preoperative tumor treatment have made it possible for most patients with bone cancer in an arm or leg to avoid radical surgical procedures (removal of the entire limb). However, most patients who undergo limb-sparing surgery need reconstructive surgery to maximize limb function .
• Chemotherapy is the use of anticancer drugs to kill cancer cells. Patients who have bone cancer usually receive a combination of anticancer drugs. However, chemotherapy is not currently used to treat chondrosarcoma.
• Radiation therapy, also called radiotherapy, involves the use of high-energy x-rays to kill cancer cells. This treatment may be used in combination with surgery. It is often used to treat chondrosarcoma, which cannot be treated with chemotherapy, as well as ESFTs. It may also be used for patients who refuse surgery.
• Cryosurgery is the use of liquid nitrogen to freeze and kill cancer cells. This technique can sometimes be used instead of conventional surgery to destroy the tumor

Source: TMC