Prognosis after metastases in osteosarcoma

Data from 106 patients with osteosarcoma who developed metastases during treatment were analyzed for prognostic factors for postmetastic survival time. Patients diagnosed in 1971 or later received more intensive chemotherapy and had significantly longer postmetastatic survival time than those diagnosed in 1970 or earlier (P = 0.002). Patients whose metastasis occurred 13 or more months after diagnosis had signicantly longer postmetastatic survival time than those whose metastasis occurred during the first 12 months after diagnosis (P = 0.005). Life-table regression analysis revealed an interaction between "year of diagnosis" and "months to metastasis" which provided a postmetastatic survival advantage for those having metastasis after diagnosis over metastasis at diagnosis for patients diagnosed in 1971 or later but not for those diagnosed in 1970 or earlier (P = 0.093).