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.
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).
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. This can occur with both benign and malignant tumors. Even benign tumors can spread locally and weaken the surrounding bone. If the tumor compresses the surrounding nerve it can cause pain, numbness, or tingling in the extremities.
If the surrounding blood vessels are compressed, it can affect the blood flow to the extremities.
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.
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 primary 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 of age. 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 of age. It is slightly more common in males and can potentially spread to the lungs and lymph nodes. Chondrosarcoma 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%.
- Malignant fibrous histiocytoma (MFH) affects the soft tissues, including muscle, ligaments, tendons, and fat. It is the most common soft-tissue malignancy in later adult life, usually occurring in people 50-60 years of age. It most commonly affects the extremities and is about twice as common in males as females. MFH also has a wide range of severity. The overall five-year survival rate is about 35%-60%.
- Fibrosarcoma is much more rare than the other bone tumors. It is most common in people 35-55 years of age. It most commonly affects the soft tissues of the leg behind the knee. It is slightly more common in males than females.
- Chordoma is a very rare tumor with an average survival of about six years after diagnosis. It occurs in adults over 30 years of age and is about twice as common in males as females. It most commonly affects either the lower or upper end of the spinal column.
In addition to bone cancer, there are various types of benign bone tumors. These include osteoid osteoma, osteoblastoma, osteochondroma, enchondroma, chondromyxoid fibroma, aneurysmal bone cyst, unicameral bone cyst, and giant cell tumor (which has the potential to become malignant). As with other types of benign tumors, these are not cancerous.
There are two other relatively common types of cancer than develop in the bones: lymphoma and multiple myeloma. Lymphoma, a cancer arising from the cells of the immune system, usually begins in the lymph nodes but can begin in the bone. Multiple myeloma begins in the bones, but it is not usually considered a bone tumor because it is a tumor of the bone marrow cells and not of the bone cells.
There are many different methods available for your doctor to treat bone cancer. The best treatment is based on the type of bone cancer, the location of the cancer, how aggressive the cancer is, and whether or not the cancer has invaded surrounding or distant tissues (metastasized). There are three main types of treatment for bone cancer: surgery, chemotherapy, and radiation therapy. These can be used either individually or combined with each other.
Surgery is often used to treat bone cancer. The goal of surgery is usually to remove the entire tumor and a surrounding area of normal bone. After the tumor has been removed, a pathologist examines it to determine if there is normal bone completely surrounding the tumor. If a portion of the cancer is left behind, it can continue to grow and spread, requiring further treatment.
If the tumor specimen has normal cells completely surrounding it, there is a much better chance that the entire tumor has been removed and less chance for recurrence. Historically, amputations were frequently used to remove bone cancer.
Newer techniques have decreased the need for amputation. In many cases, the tumor can be removed with a rim of normal bone without the need for an amputation. Depending on the amount of bone removed, the surgeon will replace something in its location. For smaller areas, this may be either bone cement or a bone graft from another place in your body or from the bone bank.
For larger areas, the surgeon may place larger grafts from the bone bank or metal implants. Some of these metal implants have the ability to lengthen when used in growing children.
You may be referred to a medical oncologist for chemotherapy. This is the use of various medications used to try to stop the growth of the cancer cells. Chemotherapy can be used prior to surgery to try to shrink the bone tumor to make surgery easier. It can also be used after surgery to try to kill any remaining cancer cells left following surgery.
You could also be referred to a radiation oncologist for radiation therapy. The radiation therapy uses high-energy X-ray aimed at the site of the cancer to try to kill the cancer cells. This treatment is given in small doses daily over a period of days to months. As with chemotherapy, radiation therapy can be used either before or after a potential surgery, depending on the specific type of cancer.