Repeated chemosensitivity testing in patients with epithelial ovarian carcinoma

Epithelial ovarian carcinoma (EOC) is a highly chemosensitive tumor, but most patients with advanced EOC initially responding to first-line chemotherapy will eventually relapse. Chemosensitivity testing may offer an opportunity for the optimal selection of chemotherapeutic agents for individual patients. In the present retrospective analysis we have examined the changes in chemosensitivity profiles during the course of the disease. Chemosensitivity was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) test. Two or more samples at least 14 days apart were obtained from 34 patients with ovarian cancer. Chemoresistance increased significantly at the second measurement only for paclitaxel and carboplatin, the most frequently used cytotoxic drugs. No significant difference compared to baseline was observed at subsequent measurements for any other cytotoxic agent studied, although a non-significant trend for increased chemoresistance was observed. In conclusion, in the present cohort only paclitaxel and carboplatin chemosensitivity changed significantly, although to a limited extent, during the course of the disease. In contrast to a limited increase of paclitaxel and carboplatin chemoresistance, no significant changes were observed for other cytotoxic agents examined. The present data indicate that chemoresistance increases, to a modest extent, against the drug most frequently used, but remains relatively stable during the course of disease, especially for agents that are not used in the therapeutic regimen.