The epidemiology of osteosarcoma

Osteosarcoma derives from primitive bone-forming mesenchymal cells and is the most common primary bone malignancy. The incidence rates and 95% confidence intervals of osteosarcoma for all races and both sexes are 4.0 (3.5-4.6) for the range 0-14 years and 5.0 (4.6-5.6) for the range 0-19 years per year per million persons. Among childhood cancers, osteosarcoma occurs eighth in general incidence and in the following order: leukemia (30%), brain and other nervous system cancers (22.3%), neuroblastoma (7.3%), Wilms tumor (5.6%), Non-Hodgkin lymphoma (4.5%), rhabdomyosarcoma (3.1%), retinoblastoma (2.8%), osteosarcoma (2.4%), Ewing sarcoma (1.4%). The incidence rates of childhood and adolescent osteosarcoma with 95% confidence intervals are: Blacks 6.8 / year /million, Hispanics 6.5 / year / million and Caucasians 4.6 / year /million. Osteosarcoma has a bimodal age distribution, having the first peak during adolescence and the second peak in older adults. The first peak is in the 10 to 14-year-old age group, coinciding with the pubertal growth spurt. This suggests a close relationship between the adolescent growth spurt and osteosarcoma. The second osteosarcoma peak is in adults older than 65 years of age in which osteosarcoma is more likely to represent a second malignancy, frequently related to Paget’s disease. The incidence of osteosarcoma has always been considered to be higher in males than in females, at a rate of 5.4 per million persons per year in males versus 4.0 per million in females, with a higher incidence of osteosarcoma in blacks (6.8 per million persons per year) and in Hispanics (6.5 per million) than in whites (4.6 per million). Osteosarcoma commonly occurs in the long bones of the extremities near the metaphyseal growth plates. The most common sites are femur (42%, with 75% of tumors in the distal femur), tibia (19%, with 80% of tumors in the proximal tibia), and humerus (10%, with 90% of tumors in the proximal humerus). Other locations of note are the skull or jaw (8%) and pelvis (8%). Cancer deaths due to bone and joint malignant neoplasms represent 8.9 percent of all childhood and adolescent cancer deaths. Death rates for osteosarcoma have been declining by about 1.3 percent per year. The overall 5-year survival rate for osteosarcoma is 68%, without significant gender difference. Age of the patient is correlated with survival with the poorest survival for older patients. Complete surgical excision is important to ensure an optimum outcome. Tumor staging, presence of metastases, local recurrence, chemotherapy regimen, anatomic location, size of the tumor, and percentage of tumor cells destroyed after neoadjuvant chemotherapy have effects on outcome.