Determination of in vitro drug sensitivity to a panel of cystostatic drugs and interferon alpha-2b in patients with renal cell carcinoma.

Fresh operative cells from 27 renal cell carcinomas (RCC) were cultured in vitro for the determination of in vitro drug sensitivity. Two samples were not culturable. Incubation was carried out in triplicate in the presence and absence of various concentrations of chemotherapeutic agents. Sensitivity of the tumour cells to interferon-alpha (IFN-alpha), cisplatin (CDDP), mitomycin C (MMC), vinblastine (VBL), doxorubicin (DOX), etoposide (ETOP), bleomycin (BLM), vincristine (VCR) were tested by a colorimetric assay using MTT. A preexposure viability over 75% was essential for in vitro drug sensitivity assay (IVDSA). Sensitivity was determined by a more than 50 +/- 2 SD% reduction from the control absorbance. All eight drugs in their low concentrations exhibited cell proliferation inhibition in 0-12% of RCCs. On the other hand, IFN-alpha in its higher concentration (60 IU/ml) was effective in 88% of RCCs. After IFN, CDDP was found to be the second most effective drug in its higher concentration (36% efficacy). The results indicate that IFN appears to be the most effective in vitro agent in our 25 RCCs and the clinical trials either as a monotherapy or multiple combinations of various agents should include IFNs for the treatment of RCC.