Adjuvant chemoradiation with 5-fluorouracil/leucovorin versus S-1 in gastric cancer patients following D2 lymph node dissection surgery: A feasibility study

Purpose: We retrospectively analyzed the feasibility and adverse events for two regimens, postoperative chemoradiation (CRT) with 5-fluorouracil/leucovorin (5-FU/LV) compared to S-1 in D2-resected gastric cancer patients. Patients and Methods: The study included 405 gastric cancer patients who underwent curative gastrectomy with D2 lymph node dissection and received adjuvant therapy between January 2008 and July 2009. Feasibility and adverse events for the CRT and S-1 regimens were analyzed. Results: Out of the 405 patients, 244 (60.2%) had CRT and 161 (39.8%) had S-1 treatment. The regimen was selected based on the preferences of the physician and the patient. S-1 was more frequently administered to patients with older age (age ≥70) and those with early-stage disease (stage II). The stage was significantly more advanced in the CRT group compared to the S-1 group (S-1 vs. CRT: stage II, 59.6% vs. 36.1%; stage III/IV, 28.0% vs. 48.3%, respectively; p<0.001). The completion rate of the planned therapy was significantly higher in the CRT group than in the S-1 group (95.1% vs. 72.8%, respectively; p<0.001). Regarding severe adverse events (grade 3-4), neutropenia (CRT vs. S-1; 40.2% vs. 8.7%, respectively, p<0.001), nausea (CRT vs. S-1; 5.7% vs. 0%, respectively; p=0.002) and stomatitis (CRT vs. S-1; 7.4% vs. 2.5%, respectively; p=0.034) were significantly more frequent in the CRT cohort compared to the S-1 group. Conclusion: Both adjuvant CRT with 5-FU/LV and adjuvant S-1 are safe and feasible in D2-resected gastric cancer patients. Patients with old age or early stage disease tend to prefer S-1 therapy to chemoradiation.