Osteosarcoma is a type of bone cancer that usually develops in the osteoblast cells that form bone. It occurs most often in children, adolescents, and young adults. Approximately 800 new cases of osteosarcoma are reported each year in the U.S. Of these cases, 400 are in children and teens. It occurs slightly more often in males than in females.
Osteosarcoma most commonly occurs in the long bones around the knee. Other sites for osteosarcoma include the upper leg, or thighbone, the lower leg, upper arm bone, or any bone in the body, including those in the pelvis, shoulder, and skull.
Osteosarcoma may metastasize, or spread, into nearby tissues, such as tendons or muscles. It may also metastasize through the bloodstream to other organs or bones in the body.
The exact cause of osteosarcoma is not known, but it is believed to be due to DNA mutations--either inherited or acquired after birth. Other theories and associations have been suggested as risk factors.
A risk factor is anything that may increase a person's chance of developing a disease. It may be an activity, such as smoking, diet, family history, or many other things. Different diseases have different risk factors.
Although these factors can increase a person's risk, they do not necessarily cause the disease. Some people with one or more risk factors never develop the disease, while others develop the disease and have no known risk factors.
But, knowing your risk factors to any disease can help to guide you into the appropriate actions, including changing behaviors and being clinically monitored for the disease.
Suggested risk factors for osteosarcoma include the following:
- Teenage growth spurts
- Being tall for a specific age
- Previous treatment with radiation for another cancer, especially at a young age or with high doses of radiation
- Presence of certain benign (noncancerous) bone diseases
- Presence of certain rare, inherited disorders, such as the following:
- Li-Fraumeni syndrome. A rare family predisposition to multiple types of cancers (such as soft tissue sarcomas, breast cancer, brain tumors, osteosarcoma, leukemia, melanoma, cancer of the adrenal cortex, and others) caused by a mutation in a gene--the p53 tumor-suppressor gene--that normally curbs cancer.
- Rothmund-Thompson syndrome. A rare inherited syndrome that includes skeletal problems, rashes, short stature, and an increased risk of developing osteosarcoma. It is caused by an abnormality in the REQL4 gene.
- Retinoblastoma. A malignant tumor of the retina that usually occurs in children younger than four years old.
The following are the most common symptoms for osteosarcoma. However, each individual may experience symptoms differently. Symptoms may include:
- Pain in the affected bone
- Swelling around the affected site
- Increased pain with activity or lifting
- Decreased movement of the affected limb
The symptoms of osteosarcoma may resemble other medical conditions, such as Ewing sarcoma. Always consult your doctor for a diagnosis.
In addition to a complete medical history and physical examination, diagnostic procedures for osteosarcoma may include the following:
- Multiple imaging studies of the tumor and sites of possible metastasis, such as:
- X-ray. A diagnostic test that uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs on film.
- Radionuclide bone scans. A nuclear imaging method to evaluate any degenerative and/or arthritic changes in the joints; to detect bone diseases and tumors; to determine the cause of bone pain or inflammation. This test is to rule out any infection or fractures.
- Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. This test is done to better define a mass seen on X-ray and to look for any nearby spread of tumors.
- Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce both horizontal and vertical cross-sectional images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
- Positron emission tomography (PET) scan. Radioactive-tagged glucose (sugar) is injected into the bloodstream. Tissues that use the glucose more than normal tissues (such as tumors) can be detected by a scanning machine. PET scans can be used to find small tumors that have spread or to check if treatment for a known tumor is working.
- Bone scan. An imaging test that takes a picture of the entire skeleton all at once to find out if a cancer has spread to other bones.
- Complete blood count (CBC). A measurement of size, number, and maturity of different blood cells in a specific volume of blood.
- Blood tests. These include blood chemistries.
- Biopsy of the tumor. A procedure in which tissue samples are removed (with a needle or during surgery) from the body for examination under a microscope to determine if cancer or other abnormal cells are present.
Specific treatment for osteosarcoma will be determined by your doctor based on:
- Your age, overall health, and medical history
- Extent of the disease
- Your tolerance for specific medications, procedures, or therapies
- Expectations for the course of the disease
- Your opinion or preference
Treatment may include:
- Surgery (for example, biopsy, resections, bone/skin grafts, limb salvage procedures, reconstructions)
- Radiation therapy
- Resections of metastases (spreading of the tumor to other locations)
- Rehabilitation, including physical and occupational therapy, and psychosocial adapting
- Prosthesis fitting and training
- Supportive care for the side effects of treatment
- Antibiotics to prevent and treat infections
- Continued follow-up care to determine response to treatment, detect recurrent disease, and manage the side effects of treatment
Many patients, particularly those with higher grade tumors, will receive a combination of treatments.
Prognosis for osteosarcoma greatly depends on:
- The extent of the disease
- The size and location of the tumor
- The pathologic grade of the cancer
- Presence or absence of metastasis
- The tumor's response to therapy
- Your age and overall health
- Your tolerance of specific medications, procedures, or therapies
- New developments in treatment
A person who was treated for bone cancer as a child or adolescent may develop effects months or years after treatment ends. These effects are called late effects. The kind of late effects one develops depends on the location of the tumor and the way it was treated.
Some types of treatment may later affect fertility. If this side effect is permanent, it will cause infertility, or the inability to have children. Both men and women can be affected.
As with any cancer, prognosis and long-term survival can vary greatly from person to person. Every individual is unique and treatment and prognosis is structured around your needs. Prompt medical attention and aggressive therapy are important for the best prognosis. Continuous follow-up care is essential for a person diagnosed with osteosarcoma. Side effects of radiation and chemotherapy, as well as second malignancies, can occur in survivors. New methods are continually being discovered to improve treatment and decrease side effects.
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Online Resources of Bone Disorders