Your body has 206 bones. These bones serve multiple different functions. First, your bones provide structure to your body and help provide its shape. Muscles attach to the bones and allow you to move. Without the bones, your body would become a pile of soft tissues without structure, and you would be unable to stand, walk, or move. Second, the bones help to protect the more fragile organs of the body. For example, the bones of the skull protect the brain, the vertebrae of the spine protect the spinal cord, and the ribs protect the heart and lungs. Third, the bones contain bone marrow, which makes and stores new blood cells. Finally, the bones help control your body's collection of various proteins and nutrients including calcium and phosphorus.

Bone cancer is caused by a problem with the cells that make bone. More than 2,000 people are diagnosed in the United States each year with a bone tumor. Bone tumors occur most commonly in children and adolescents and are less common in older adults. Cancer involving the bone in older adults is most commonly the result of metastatic spread from another tumor.

There are many different types of bone cancer. The most common bone tumors include osteosarcoma, Ewing's sarcoma, chondrosarcoma, malignant fibrous histiocytoma, fibrosarcoma, and chordoma.

• Osteosarcoma is the most common primary malignant bone cancer. It most commonly affects males between 10 and 25 years old, but can less commonly affect older adults. It often occurs in the long bones of the arms and legs at areas of rapid growth around the knees and shoulders of children. This type of cancer is often very aggressive with risk of spread to the lungs. The five-year survival rate is about 65%.

• Ewing's sarcoma is the most aggressive bone tumor and affects younger people between 4-15 years of age. It is more common in males and is very rare in people over 30 years old. It most commonly occurs in the middle of the long bones of the arms and legs. The three-year survival rate is about 65%, but this rate is much lower if there has been spread to the lungs or other tissues of the body.

• Chondrosarcoma is the second most common bone tumor and accounts for about 25% of all malignant bone tumors. These tumors arise from the cartilage cells and can either be very aggressive or relatively slow-growing. Unlike many other bone tumors, chondrosarcoma is most common in people over 40 years old. It is slightly more common in males and can potentially spread to the lungs and lymph nodes. Chondrosracoma most commonly affects the bones of the pelvis and hips. The five-year survival for the aggressive form is about 30%, but the survival rate for slow-growing tumors is 90%.

What are the symptoms of bone cancer?

The most common symptom of bone tumors is pain. In most cases, the symptoms become gradually more severe with time. Initially, the pain may only be present either at night or with activity. Depending on the growth of the tumor, those affected may have symptoms for weeks, months, or years before seeking medical advice. In some cases, a mass or lump may be felt either on the bone or in the tissues surrounding the bone. This is most common with MFH or fibrosarcoma but can occur with other bone tumors. The bones can become weakened by the tumor and lead to a fracture after little or no trauma or just from standing on the affected bone. Fever, chills, night sweats, and weight loss can occur but are less common. These symptoms are more common after spread of the tumor to other tissues in the body.

How is bone cancer diagnosed?

The first thing your doctor will do is to take a complete medical history. This will give your doctor clues as to your diagnosis. Some types of cancer are more common in people if they have close family members that have had that type of cancer. A description of your symptoms can help your doctor identify the possibility of bone cancer from other possible causes. Next, a complete physical examination can help find the cause of your symptoms. This may include testing your muscle strength, sensation to touch, and reflexes. Certain blood tests can be ordered that can help to identify a possible cancer.

Next, your doctor will likely order some imaging studies. Plain x-rays are often ordered first. In some cases, if the cancer is identified very early it may not show up on plain x-rays. The appearance of a tumor on the x-ray can help determine the type of cancer and whether or not it is benign or malignant. Benign tumors are more likely to have a smooth border while malignant tumors are more likely to have a ragged border. This is because the benign tumors typically grow more slowly and the bone has time to try to surround the tumor with normal bone. Malignant tumors are more likely to grow more quickly, not giving the normal bone a chance to surround the tumor.
A CT scan (CAT scan or computed tomography) is a more advanced test that can give a cross sectional picture of your bones. This test gives very good detail of your bones and is better able to identify a possible tumor. It also gives additional information on the size and location of the tumor