Cytotoxicity of CPT-11 for gastrointestinal cancer cells cultured on fixed-contact-sensitive plates.

The cytotoxicity of SN-38, the major metabolite of CPT-11 (7-ethyl-10-[4-(1-piperidino)-1- piperidino]carbonyloxycamptothecin, was compared among gastrointestinal carcinomas of every organ, and between primary and metastatic lesions of every organ-originated gastrointestinal carcinoma, by an in vitro anticancer drug sensitivity test using fixed-contact-sensitive plates. The rates of cases having a high response (percent survival 75% or lower) to SN-38 but a low response (percent survival above 75%) to cisplatin, mitomycin C (MMC), adriamycin (ADM) and 5-fluorouracil (5-FU) were 14.6, 19.4, 15.6 and 27.0%, respectively. While, the rates of cases having a high response to cisplatin, MMC, ADM and 5-FU but a low response to SN-38 were 7.3, 2.8, 9.4 and 13.5%, respectively. Each of the former rates were higher than each of the latter rates. In particular, the former rate for MMC was significantly higher than the latter rate (p = 0.04). Two cases with colon cancer showed a high response only to SN-38. The percent survival of primary lesions in colon cancer was significantly lower than that in stomach cancer. The rates of hepatocellular carcinoma cases having a high response to SN-38 but a low response to cisplatin, MMC, ADM and 5-FU were 16.7, 16.7, 0 and 25%, respectively. Only one case had a high response to 5-FU but a low response to SN-38. The percent survival of metastatic lesions in pancreatic cancer was significantly lower than that of primary lesions. From this study, we recommend the further clinical trial of CPT-11 for colon and hepato-cellular cancers.