DOSE-ESCALATION WITH PHARMACOKINETICS MONITORING IN METHOTREXATE CHEMOTHERAPY OF OSTEOSARCOMA

This paper evaluates the influence of pharmacokinetics monitoring of H DMTX in the treatment of localized operable previously untreated high grade osteosarcoma. 44 patients (group 1) received a T10 protocol with dose adapted only to age. 27 other patients (group 2) had a pharmacok inetics monitored dose adaptation of MTX. The pharmacokinetics monitor ing leads to higher dosage, higher area under the concentration/time c urve and permits higher toxicity to be avoided. The higher dose intens ity of MTX gave higher histologic response rate (66 % compared to 45 % ) and higher 5 year disease free survival (92 % compare to 76 %). HDMT X treatment of osteosarcoma should be dose adapted to indivi-dual phar macokinetics.