Cancer chemotherapy chemosensitivity testing is useful in evaluating the appropriate adjuvant cancer chemotherapy for stages III/IV gastric cancers without peritoneal dissemination

Background: Because of the low chemosensitivity of gastric cancer to conventional antitumor agents, the role of adjuvant chemotherapy for patients with advanced gastric cancer is controversial. We have previously proposed the necessity to evaluate the appropriateness of particular adjuvant cancer chemotherapies in individual advanced gastric cancer patients using chemosensitivity testing. In the present study, we compared the chemosensitivity and clinical outcomes of patients with Stages III and IV gastric cancer. Patients and Methods: A total of 282 patients with advanced gastric cancer were analyzed retrospectively in terms of chemosensitivity as detected by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and survival outcome after surgery. Patients were split into groups according to Stage III or IV gastric cancer, then categorized into those that received surgery without chemotherapy (surgery-alone), and those that received adjuvant chemotherapy, for which all the evaluable cases were further divided into sensitive and resistant cases as determined by MTT assay. Results: For Stage III gastric cancer patients, the sensitive group had a more favorable survival outcome than the other two groups. For Stage IV gastric cancer patients, the sensitive groups, had a more favorable survival outcome than the other two groups, but only in the absence of peritoneal dissemination. Conclusion: Chemosensitivity testing, based on the MTT assay, was useful in evaluating the appropriate cancer chemotherapy for patients with Stages III/IV gastric cancer without peritoneal dissemination.