Clinical correlations with chemosensitivities measured in a simplified tritiated thymidine incorporation assay in patients with malignant effusion.

Utilizing a simplified tritiated thymidine incorporation assay, in vitro chemosensitivity of tumor cells obtained from malignant effusions was assessed and, in these patients, chemotherapeutic drugs were administered directly into the peritoneal or pleural cavity. Then, correlations between in vitro sensitivity and clinical response were investigated. Fifteen (88%) of 17 patients with various carcinomas gave evaluable chemosensitivity results. All 15 patients were evaluable for in vitro-in vivo correlations. This assay had an accuracy of 75% for prediction of response (3 of 4) and an accuracy of 82% for prediction of resistance (9 of 11), when the peak achievable plasma concentrations were selected as the concentrations used for in vitro sensitivity testing, adopting 80% inhibition of thymidine incorporation as cutoff level.