When cells in the bone develop genetic mutations, they can start to divide at an abnormally rapid rate, forming a tumor. Bone tumors that can break down the surrounding bone tissue and invade other tissues are considered cancerous. Bone cancer can originate within the bone itself or can be the result of cancer spreading from other organs. Depending on the type of bone cancer, it can be fatal.
Primary vs. Secondary Cancer
Bone cancer is divided into two different forms. Primary bone cancer, according to the National Cancer Institute, describes cancer that actually begins within the bone. Secondary bone cancer is the result of cancer that originates elsewhere in the body (such as the prostate, breast or lung) and spreads to the bones. Primary bone cancer is much less common than secondary bone cancer.
Types of Primary Bone Cancer
Primary bone cancers are named after the kind of cell from which they originated. The Mayo Clinic explains that osteosarcomas are cancers that originate within the bone cells. Chondrosarcomas are cancers that are derived from the cartilage that surrounds bones. Ewing's sarcoma is another kind of primary cancer, but it's not clear what kind of cells form Ewing's sarcoma. Ewing's sarcoma can also occur in the soft tissues (such as fat) around the muscles.
Symptoms
One of the more common symptoms of bone cancer is bone pain that can be combined with tenderness or swelling around the tumor. As the cancer breaks down bone tissue it can cause the bones to get weaker, which can cause them to break easily. Patients can also feel fatigued and experience sudden weight loss.
Treatment
The American Cancer Society states that different kinds of bone cancers are treated differently, but there are three main approaches. Surgery can be used to cut out the cancerous tissue. Radiation treatment uses high-energy x-rays which damage rapidly dividing cells by chemically altering their DNA. Because bone cancer cells divide very rapidly, the radiation predominantly affects the cancerous cells. The American Cancer Society also notes that some kinds of osteosarcomas can be treated with chemotherapy, which uses drugs that poison rapidly dividing cells (either by damaging their DNA or by blocking the process of replication).
Stages and Prognosis
The American Cancer Society notes that an estimated 2,570 cases of primary bone cancer were diagnosed in 2009, and 1,470 of those cases will ultimately be fatal. The prognosis for bone cancer depends in large part on the "stage" of the cancer. Stage I bone cancers have cells that appear similar to regular bone and the cancer is limited to one place on the bone. Stage II cancer is still confined to one part of the bone but the cells appear abnormal. Stage III bone cancer describes bone cancer that has spread to multiples parts of the bone. Stage IV cancer describes cancer that has spread to other tissues in the body. Most bone cancers are fatal when they begin to spread throughout the body because they can affect the lungs, liver or brain.
