Individual chemosensitivity of in vitro proliferating mammary and ovarian carcinoma cells in comparison to clinical results of chemotherapy.

Cell lines established from advanced mammary and ovarian carcinomas were assayed for the inhibition of in vitro proliferation by various antineoplastic drugs. The assays were performed with multiple experimental cultures derived from stock cultures of the tumor cell lines in early passages of the cultivation. As determined by comparison of the 50% inhibition of in vitro growth, differential sensitivity of the individual cell lines was observed. Based on the 2-h plasma level of the drugs as discriminatory threshold between resistance and sensitivity, the in vitro effectiveness of each drug on the individual cell lines was compared with the clinical results of chemotherapy applied to the corresponding patients. In total, positive in vitro/in vivo correlations were observed in 39 of 42 cases. The 17 cell lines evaluated retrospectively were resistant to those drugs which had been tried unsuccessfully during chemotherapy. Among the 25 cases tried prospectively 11 cases showed sensitivity in vitro and in vivo, and furthermore 11 prospective cases were resistant in vitro and in vivo.