Bone cancer is a malignant tumor that develops from the cells of the bone.
There are three main types of bone cancer:
- Osteosarcoma, which arises in new tissue in growing bones. This is the most common type of bone cancer. It occurs most often in teens.
- Chondrosarcoma which arises in cartilage
- Ewing's sarcoma, which may arise in immature nerve tissue in the bone marrow.
Cancer that starts in the bone is not the same as cancer that spreads to the bone from another part of the body. Cancer that spreads is called metastatic. It usually comes from the breasts, lungs and or other organs.
The signs of bone cancer depend on where and how large the cancer is. Common signs include:
- Pain in the bone and swelling. This is sometimes worse at night. Pain relievers don't reduce the pain.
- Unexplained fractures due to weakened bones
- Weight loss
- Difficulty moving
Causes and Risk Factors
Most people with bone cancers to do not have any apparent risk factors. People who have the following may be at higher risk of getting bone cancer:
- Inherited genes: a few bone cancers (especially osteosarcomas) appear to have a hereditary basis
- Retinoblastoma, a rare eye cancer of children. Children with an inherited form of retinoblastoma also have an increased risk for developing osteosarcoma. Also, the radiation used to treat children with retinoblastoma increases their risk of osteosarcoma in the bones of the skull.
- Paget's disease, a benign but precancerous condition that affects one or more bones. This mostly affects people older than 50 with the formation of abnormal bone tissue. Bone cancer may develop in 5% to 10% of severe cases of Paget's disease, usually when many bones are affected.
- Many overgrowths of bone tissue
- Many benign tumors formed by bone and cartilage. Most of these are cured by surgery. There is a slight risk that they may develop into cancer.
- Multiple benign cartilage tumors, which put people at a slightly higher risk of developing bone cancer
- Exposure to large doses of radiation
There is no evidence that injury to a bone leads to bone cancer.
Bone cancer is usually diagnosed on the basis of the patient's symptoms, a physical examination, imaging tests and blood tests.
Imaging tests used to diagnose bone cancer include:
- Computed tomography (CT scan), which uses a rotating X-ray beam to create a series of pictures of the bone from many angles. A dye may be injected into a vein before the CT scan is done to make it easier to see.
- Magnetic resonance imaging (MRI), which uses magnets and radio waves instead of radiation to produce computer-generated pictures. The pictures look like those of a CT scan, but are more detailed.
- Bone scan, which helps show if a cancer has spread to other bones. It also can show how much damage the cancer has caused.
To confirm a diagnosis of bone cancer is it is necessary to examine samples of tissue or bone cells under a microscope. This will also help determine whether the cancer started in the bone or spread from some other part of the body.
Treatment depends on the type, stage and location of the cancer. It will also depend on how rapidly the tumor is growing. Treatment options include: