Evaluation of usefulness of in-vitro drug sensitivity testing for adjuvant chemotherapy of stomach cancer

Abstract

Background. The selection of effective drugs is the key for tumor chemotherapy. The succinic dehydrogenase inhibition (SDI) method, the simplest chemosensitivity test, is widely used at many institutions in Japan. As adequate proof of the usefulness of this test in the clinical setting has not yet been established, a prospective randomized study was undertaken. Methods. An adjuvant chemotherapy study incorporating the SDI test was performed in patients with gastrectomized stomach cancer. Fifteen test centers were set up throughout Japan, and the tests were performed on test specimens collected from neighboring institutions. In order to insure homogeneity of the test techniques, both intra- and inter-institutionally, simulation tests in tumor-bearing nude mice were carried out simultaneously. Three hundred and thirty-three eligible patients were categorized as stratum I (curative resection) or stratum II (non-curative resection) and were randomly allocated to three chemotherapy groups group A (mitomycin C), group B (doxorubicin), and group C (cisplatin), Correlations between survival rates and the inhibition index (II; a percentage value calculated from the optical density of tumor cell suspersions caltured with the anticancer drugs), which was arbitrarily divided into three categories: ≥60%; 59%–30%; and ≤29%, were analyzed in the three groups. Results. Significant differences in survival rates, in terms of the II, were shown in the stratum I group C (cisplatin), whereas no difference in terms of II was found in groups A and B. Conclusion. The SDI sensitivity test was found to be useful for cisplatin; however, the test failed to show usefulness for mitomycin C and doxorubicin.