Osteosarcoma is a type of bone cancer. Bone cancers are rare; only about 2,000 cases are diagnosed yearly in the United States, according to MayoClinic.com. Osteosarcoma makes up approximately 35 percent of these bone cancers, making it the most common kind. Long bones in the legs and arms, such as the humerus or the femur, are most commonly affected, but osteosarcoma can occur in any bone.
Significance
Osteosarcoma is a rare kind of cancer; about 900 individuals in the United States are newly diagnosed with the disease yearly, according to the American Cancer Society, with nearly 400 of those diagnoses made in individuals younger than 20. Teenagers and young adults are the most commonly affected age group, with the majority of diagnoses occurring in patients ages 10 to 30.
Types
The American Cancer Society describes three subtypes of osteosarcoma; these subtypes are classified based on how the cells look under a microscope and on X-rays. High-grade osteosarcomas are aggressive, fast-growing cancers, and their cells do not resemble healthy bone cells. Different kinds of high-grade osteosarcomas include chondroblastic, fibroblastic and small-cell osteosarcomas. Intermediate-grade osteosarcomas are uncommon and include the subtype periosteal osteosarcoma. The low-grade category consists of slow-growing osteosarcomas and includes intramedullary or intraosseous well-differentiated osteosarcomas.
Diagnosis
Symptoms of osteosarcoma can include bone pain or swelling that is persistent and never fully goes away. This may also happen in a joint. Tests such as X-rays, CT scans, MRIs and bone scans can help diagnose the disease. For a definitive diagnosis, a bone biopsy will be done, which involves removing a small piece of bone. This sample is examined microscopically to confirm a cancer diagnosis and to classify the type of osteosarcoma.
Treatment
The specific course of treatment depends on the stage and extent of the disease, and the grade, or aggressiveness, of the cancer cells. Surgery to remove the tumor or the bone is typically done, along with chemotherapy or radiation therapy after the operation to kill any remaining cancer cells. If the tumor is not operable or if there is remaining cancer, radiation therapy may be given to shrink the remaining tumor, according to the National Cancer Institute. Clinical trials may be an option for some patients; these closely monitored research studies administer new treatments that may be more effective than current treatments.
Time Frame
For osteosarcoma that is localized and hasn't spread to distant organs, the five-year survival rate is 60 to 80 percent, according to the American Cancer Society. For osteosarcomas that have metastasized to distant organs, that survival rate drops to 15 to 30 percent. If the cancer has spread only to the lungs or if the metastases can be surgically removed, the American Cancer Society puts the survival rate at nearly 40 percent.
