Resistance to anticancer drugs of well differentiated gastric adenocarcinoma with venous invasion

A comparison of the chemosensitivity of well-differentiated human gastric cancer tissues was made between histological venous invasion positive (v (+)) and negative (v (-)) tissues, using the succinate dehydrogenase inhibition (SDI) test. These tissues obtained at the time of surgery were exposed to six anticancer drugs: carboquone (CQ), adriamycin (ADM), mitomycin C (MMC), aclacinomycin A (ACR), cisplatin (DDP) and 5-fluorouracil (5-FU). Chemosensitivity was judged to be positive when the succinate dehydrogenase (SD) activity of the drug exposed cells decreased to below 50% of that of control cells. Decrease in the SD activity was more apparent in the v(-) tissues than in the v(+) tissues, exposed to the anticancer drugs and in particular to ADM (P < 0.01), MMC (P < 0.02) and DDP (P < 0.05). The sensitivity rates to all six anticancer drugs were lower in the v(+) tissues. The resistance rates to all drugs tested were 0% in the v(-) tissues, but 21% in the v(+) tissues. In light of these observations, patients with gastric cancer of the well differentiated type and the histological venous invasion, will probably show a less positive response to cancer chemotherapy.