Clinical value of in vitro drug sensitivity testing based on short-term effects on dna and rna metabolism in ovarian cancer

The hypothesis that in vitro chemosensitivity testing could predict clinical outcome was tested in women with ovarian cancer. Short‐term drug effects on DNA and RNA metabolism (by inhibition of 3H‐thymidine and 3H‐uridine incorporation) were measured in primary cultures of tumor cells. In vitro inhibitory effects were found with the four drugs tested: cisplatin, adriamycin, melphalan, and methotrexate. From data based on impaired RNA and/or DNA metabolism (≥ 20% inhibition), correct prediction of “sensitivity” was 79% and that of “resistance” was 84%. An analysis of the predictive value of both assays, used singly or together, revealed a high specificity but moderate sensitivity; the best positive predictive value (94%) was obtained when both RNA and DNA metabolisms were impaired. Our results support the idea that two subsets of patients who are being considered for cytotoxic chemotherapy can be selected: those who may benefit from treatment and those who may not, regardless of the drugs tested in vitro or used in vivo.