Stratified phase II trial to establish the usefulness of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST) for advanced gastric cancer

BACKGROUND: We conducted a multicenter phase II trial to assess the suitability of three types of chemotherapy (docetaxel plus S-1, irinotecan plus S-1, or S-1 alone) for patients with advanced gastric cancer by means of the collagen gel droplet embedded culture-drug sensitivity test (CD-DST). To our knowledge, this is the first multicenter clinical trial that has employed CD-DST to choose anticancer agents for the treatment of advanced gastric cancer. METHODS: Subjects (n = 64) were patients with advanced or recurrent gastric cancer. Patients were allocated to one of the treatment regimens on the basis of CD-DST results. Outcome of the patients was compared between the groups deemed chemosensitive or chemoresistant by the CD-DST. RESULTS: Thirty-three patients showed high sensitivity (T/C ratio <60 %) to at least one type of anticancer agent (sensitive group), and 31 showed low sensitivity (T/C ratio ≥60 %) to all agents (resistant group). Specifically, the 1-year survival rate was significantly higher in the sensitive group (78.5 %; 95 % CI, 67.2–94.7 %) than in the resistant group (54.7 %; 95 % CI, 38.7–74.3 %; P = 0.019), whereas time to progression (TTP) was significantly longer in the sensitive group (59.8 %; 95 % CI, 48.2–81.7 %) than in the resistant group (30.0 %; 95 % CI 13.6–46.4 %; P = 0.023). Median survival time was also significantly longer in the sensitive group (15.5 months; 95 % CI, 12.8–18.2) than in the resistant group (12.5 months; 95 % CI, 10.2–14.9; P = 0.038). CONCLUSIONS: CD-DST predicts the outcome of patients undergoing chemotherapy for advanced gastric cancer, presumably through evaluating chemosensitivity.