Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

Chemosensitivity testing for irinotecan (CPT-11) in ovarian and endometrial carcinomas

M Koshiyama MD 1,2, M Kinezaki PhD 3, H Fujii MD 1,2, S Ohgi MD 1, M Yoshida MD 1

1 Dept Obstetrics and Gynecology,, 3 Dept Pharmacology, Tenri Hospital, Tenri, Nara;, 2 Dept Obstetrics and Gynecology, Osaka National Hospital, Chuoku, Osaka; Japan,

AIM: To investigate the anti-tumor activity of irinotecan (CPT-11) against gynecologic carcinomas. METHODS: Using a MTT assay, we designed an in vitro chemosensitivity test for irinotecan, and compared its antitumor effects to cisplatin against gynecologic carcinomas removed from 49 patients. RESULTS: The mean tumor inhibition rate (I.R.: %) for irinotecan was relatively inferior to the I.R. for cisplatin in both ovarian and endometrial carcinomas [40.2 vs 53.2 and 43.5 vs 58.0] (p<0.05, respectively). In the ovarian carcinomas, 13 (48.1%) of the 27 cases were irinotecan-sensitive (I.R.?50%), and 77% of the tumors were judged to be irinotecan and/or cisplatin-sensitive. There were no significant differences in the I.R. for irinotecan among the various histologic subtypes. Comparing the in vitro sensitivity to irinotecan with the clinical responses in the 8 patients who received irinotecan, the overall accuracy of the MTT assay for evaluating the clinical effectiveness was 75% (6/8). In the endometrial carcinomas, we found 9 (40.9%) of the 22 cases to be irinotecan-sensitive. The I.R. for irinotecan in G1 carcinomas [33.5] was significantly lower than in G2 carcinomas [59.3] (p<0.05). CONCLUSIONS: Our data suggest that irinotecan appears to have moderate antitumor activity in vitro against ovarian and endometrial carcinomas. Furthermore, there were differences in irinotecan sensitivity among the different histologic subtypes of ovarian carcinomas, but not endometrial carcinomas.

KEY WORDS: ovarian carcinomas, irinotecan, endometrial carcinomas.

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Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on chemotherapy.