Osteosarcoma, also called osteogenic sarcoma, is a type of bone cancer that develops in the osteoblast cells that form the outer covering of bone. It occurs most often in children, adolescents and young adults. Approximately 900 new cases of osteosarcoma are reported each year in the U.S. It occurs slightly more often in males than in females, and represents 5 percent of all childhood cancers.
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 of the foot, or into tendons or muscles. It also may 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.
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 a benign (noncancerous) bone disease.
- Presence of certain rare, inherited cancers, 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.
- Retinoblastoma – a malignant tumor of the retina that usually occurs in children younger than 5 years old.
Suggested risk factors for osteosarcoma in adults include lifestyle factors such as the following:
- High-fat diets
- Lack of exercise
- Drinking alcohol
The following are the most common symptoms for osteosarcoma; however, each individual may experience symptoms differently:
- 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 physician 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 onto 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 – a diagnostic procedure that uses a combination of large magnets, radio frequencies, and a computer to produce detailed images of organs and structures within the body. This test is done to rule out any associated abnormalities of the spinal cord and nerves.
- 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 cross-sectional images (often called slices), both horizontally and vertically, 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.
- Complete blood count – a measurement of size, number and maturity of different blood cells in a specific volume of blood.
- Blood tests – including 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; to remove tissue from the affected bone.
Specific treatment for osteosarcoma will be determined by your physician 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 – i.e., 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.
Prognosis for osteogenic sarcoma greatly depends on:
- The extent of the disease.
- The size and location of the tumor.
- 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.
As with any cancer, prognosis and long-term survival can vary greatly from person to person. Every individual is unique, and treatment and prognosis are 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 osteogenic sarcoma. Side effects of radiation and chemotherapy, as well as second malignancies, can occur in survivors of osteogenic sarcoma. New methods are continually being discovered to improve treatment and to decrease side effects.