Chemosensitivity testing of ovarian cancer: results of a rapid in vitro biochemical assay

There is a need for a predictive test which will assist in the selection of an effective cytotoxic drug and thereby, provide a means of avoiding unnecessary drug-induced toxicity and tumour resistance. In the present study, the viable fraction of the tumour cell suspension from ovarian cancer was used as targets for the effect of the drug, cisplatin, in a 3-hour in vitro assay. DNA synthesis was measured by the incorporation of 3H-thymidine as an index of proliferative activity and RNA synthesis by the incorporation of 3H-uridine as an index of protein metabolism. There was a good correlation between cell activity as determined by the uptake of thymidine and uridine. The degree of drug inhibition was variable over the spectrum of tumour histologic types; thymidine uptake was significantly inhibited by cisplatin in 53% of serous cystadenocarcinomas, and uridine uptake in 21% of tumours. A clear difference in drug effect was observed between those patients who showed clinical response and those who did not. These results support the value of this assay as an indicator of drug sensitivity of the tumour.