Prognostic significance of chemotherapy dosage characteristics in children with osteogenic sarcoma

High-dose methotrexate (HDMTX), adriamycin (ADR), and cisplatinum (CDDP) are effective agents in the treatment of osteogenic sarcoma (OS). Individual patient doses are determined by prior successful clinical trials but may be reduced due to ongoing toxicities. It is unknown whether individualized dose reductions of these drugs influence disease outcome. We retrospectively studied 27 consecutively enrolled children treated with HDMTX, ADR, and CDDP as adjuvant chemotherapy for OS, for correlations between disease outcome and several characteristics of drug dosings the cumulative MTX, CDDP, and ADR doses administered and the mean MTX blood levels for each patient. With a median follow-up of 59 months, the actuarial overall and disease-free survival rates were 70% and 59%, respectively. Factors which favorably influenced prognosis on univariate analysis were a cumulative ADR dose of > 300 mg/m2 (P = 0.0002) and a cumulative MTX dose > 114 gm/m2 (P = 0.0048). By multivariate analysis only the cumulative ADR dose > 300 mg/m2 retained prognostic value. We conclude that adjuvant chemotherapy dosages may need to be adjusted for therapeutic efficacy in addition to adjustments made for toxicity. The effect of different cumulative HDMTX and ADR dosages on prognosis in osteosarcoma patients needs to be evaluated in a prospective trial.