• Cancer

Bone Cancer: When Bone Cells Grow Out Of Control

You can thank tiny bone cells for strengthening your bones. One type of bone cells, osteoblasts, constantly lay calcium down on cartilage to create new bone. Other cells, osteoclasts, dissolve the old bone.

When these cells work properly, all is good. But when they grow out of control, bone cancer develops.

Primary bone cancer – cancer that starts in the bone cells – is a rare type of cancer, with about 3,500 new cases estimated in the U.S. in 2019, according to the American Cancer Society.

A much larger number of cancers spread to the bones from other parts of the body, such as the breast, lung, or prostate gland.

So far, medical experts aren’t certain what causes bone cancer or how to prevent it. Some types of bone cancer seem to be inherited. And exposure to large doses of radiation may increase your risk.

Signs And Types Of Bone Cancer

Symptoms of bone cancer include pain or swelling in or near a bone, although some bone cancers cause no pain. If you have bone cancer, you may notice a lump in your arms, legs, chest, or pelvis. Or you may experience a bone break without a strong impact.

The main types of bone cancer that start in the bone cells include:

Osteosarcoma, or osteogenic sarcoma, is the most common type of bone cancer. It arises from the bone-forming osteoblast cells and most often affects young people ages 10 to 19. It commonly shows up near the shoulder or knee in this age group, areas where bone is growing quickly. In older adults, it can occur in any bone, although the arms, legs, and pelvis are common sites.

Chondrosarcoma is the second most common primary bone cancer and originates in your cartilage cells. It typically doesn’t affect people under age 20. Risk increases with age, up to age 75. It’s most likely to show up where cartilage grows – pelvis, legs, arms, throat, chest wall, shoulder blade, ribs, or skull. Chondrosarcomas can be slow- or fast-growing.

Ewing sarcoma, or Ewing tumor, is most common in children through young adults. It’s rare over age 30. Ewing sarcoma, named for the man who identified this type of cancer, is most commonly found in the pelvis, ribs, shoulder blades, or the long bones of the arms and legs. White people are most likely to get this type of cancer; it’s rare in African Americans and Asian Americans.

Malignant fibrous histiocytoma (MFH) of bone, or undifferentiated pleomorphic sarcoma of bone, occurs rarely in bones of the legs or arms. It usually starts in connective tissues such as ligaments, tendons, fat, and muscle. It’s most common in middle-aged adults and older.

Fibrosarcoma also generally occurs in elderly and middle-aged adults. Although it develops more often in soft tissue, it can affect the arms, legs, and jaw.

Chordoma is a slow-growing tumor that generally occurs at the base of the skull or in the bones of the spine in adults over age 30.

Malignant giant cell tumor of bone most often affects the legs or arms of young and middle-aged adults. This type of tumor can be surgically removed but may come back, generally in the same area.

Some cancers found in the bones don’t start in bone cells. These include non-Hodgkin lymphomas and multiple myelomas, and other cancers that spread to the bones from other parts of the body.

Not all bone tumors are cancerous. These noncancerous, or benign, tumors do not spread to other parts of the body. They often can be removed with surgery if they are causing pain or interfering with body movement or function.

How Bone Cancer Is Diagnosed

After completing a history and physical, your doctor will order blood tests, to help measure certain enzymes, and perform imaging tests – such as X-rays, MRIs, and CT scans – to identify a tumor.

A biopsy, a tissue sample removed from the bone, can be studied to provide valuable information about whether bone cells are cancerous.

Treating Bone Cancer

As with all types of cancer, treatment is determined by your age and overall health and is customized to address the type, size, location, and stage of cancer. Treatment for bone cancer may include any of these primary treatment methods:

• Surgery to remove the tumor. Surgical advances allow most bone cancer patients to keep their limbs.
• Chemotherapy, which uses drugs to kill cancer cells, especially for Ewing sarcoma and osteosarcoma. Chemotherapy is usually given before surgery to shrink a tumor.
• Radiation therapy, which uses high-energy X-rays to kill cancer cells. Radiation can be used in combination with surgery to destroy stray cancer cells that remain after surgery. It also is used for people who are not a candidate for surgery.
• Cryosurgery, which uses liquid nitrogen to freeze and destroy cancer cells
• Targeted therapy, which uses medicine to target a particular type of cancer cell. A targeted therapy for giant cell tumor of the bone, for instance, prevents destruction of bone caused by osteoclast bone cells.

Source: National Cancer Institute; American Cancer Society; Bone Biopsy, Healthwise, 3/28/2019