In vitro sensitivity testing of cells of histologically typified ovarian carcinomas and carcinoma of corpus with 3H-cyclophosphamide-metabolites in the serum of man after massive dose therapy.

Cells of a carcinoma of the uterine corpus and of five ovarian carcinomas were cultured in vitro with monolayer and sandwich methods, respectively. After 24-hours-incubation with serum samples of patients treated with a massive dose of 3H-cyclophosphamide (60 mg/kg body weight i.v.)-the samples were taken at different times after application-these cultures with a chromatographically defined content of free metabolites were interpreted, guided by morphological criteria. Incubation of the cultures with serum samples taken 5 hours after application of the massive dose turned out to be a practical system for detection, before the start of therapy, of the sensitivity of malignant tumors to cyclophosphamide. Statements about the proliferation kinetics of the malignant cells, about the active ultimate form of the antitumor agent and its way of action, which are not guaranteed experimentally, are largely eliminated by this method. The justification for using 4-hydroxy- and 4-hydroperoxy-cyclophosphamide to test the sensitivity of malignant cells in vitro to cyclophosphamide was critically examined.