Addition of docetaxel to S-1 results in significantly superior 5-year survival outcomes in Stage III gastric cancer: a final report of the JACCRO GC-07 study

Purpose A phase III trial comparing S-1 and docetaxel with S-1 alone as postoperative chemotherapy for pathologically Stage III gastric cancer was conducted and clarified the superiority of the doublet in terms of 3-year relapse-free survival as the primary endpoint (67.7% versus 57.4%, hazard ratio [HR] 0.715, 95% confidence interval [CI] 0.587–0.871; p = 0.0008). This final report analyzed 5-year survival outcomes along with the incidence and pattern of late recurrences. Patients and methods Patients with histologically confirmed Stage III gastric cancer who underwent gastrectomy with D2 lymphadenectomy were randomly assigned to receive adjuvant chemotherapy with either S-1 plus docetaxel or S-1 alone. The same 912 patients who were evaluated for 3-year survival outcomes in the previous report were analyzed. Results Five-year overall survival rate of the S-1 plus docetaxel group (67.91%) was significantly superior to that in the S-1 group (60.27%; HR 0.752, 95% CI 0.613–0.922; p = 0.0059). The incidence of late recurrence at > 3 years after randomization was similar in both groups (7.3% versus 7.2%). Peritoneal dissemination was the most common pattern of late recurrence. Addition of docetaxel significantly suppressed relapse through the lymphatic (6.8% [95% CI 4.52–9.17] versus 15% [95% CI 11.76–18.30]; p < 0.0001) and hematogenous (10.2% [95% CI 7.37–12.94] versus 15.7% [95% CI 12.36–19.01]; p < 0.0137) pathways throughout the 5 years of follow-up. Conclusion The survival benefit of postoperative chemotherapy with S-1 and docetaxel in terms of 5-year overall survival rate was confirmed for patients with pathologically Stage III gastric cancer, although late recurrences were not prevented.