Survival analysis according to lymph nodes dissection and adjuvant therapy types in gastric cancer: A retrospective multicenter cohort study

Aim: While the main treatment of gastric cancer (GC) is surgery, controversy continues regarding appropriate lymph nodes dissection (LND) types and optimal adjuvant therapy after surgery. Therefore, we aim to analyze the survival outcomes of different treatment sequences in GC. Materials and methods: In total, 234 GC patients who developed recurrence after D1 or D2 LND, R0 gastrectomy were retrospectively investigated. Patients treated with following different treatment sequences were compared for time to recurrence (TTR) and overall survival (OS) of patients with recurrence: D1-LND followed by chemoradiotherapy (CRT) or chemotherapy (CT); D2-LND followed by CRT or CT. RFS and OS estimated by Kaplan-Meier method and long-rank test was used to assess hazard ratio. Results: In the whole group; there were 161 men (68.8%) and mean age was 57.9 (±1.69) years. In 4 arms, 94.8% of patients had positive lymph nodes, 42.7% of patients had pT4 stage tumor, and intestinal-type GC was present in 95 patients (40.6%). The median TTR were 14.0 (11.5–16.5), 7.0 (5.8–8.2), 13.0 (10.5–15.5), and 13.0 (10.8–15.2) months, for D1-LND + CRT; D1-LND + CT; D2-LND + CRT; and D2-LND + CT groups, respectively (HR; 95%CI:2086; 1133–3,839, P = 0,018 for D1-LND + CT group after adjusted for pN stage, PNI, and LVI). The median OS of the patients with recurrence was 29.0 months (26.8–31.2). While higher pT and pN stage, PNI and LVI positivity, undifferentiated and diffuse + mixed histological types presented with worse overall survival, treatment choices were not effect on OS. Conclusion: RT is not necessary after D2-LND but it is still a major part of adjuvant treatment after D1-LND. D2-LND may not be require to cure GC when appropriate adjuvant treatment is given after D1-LND. Keywords: Gastric cancer, Chemotherapy, Chemoradiotherapy, Survival, D1 dissection, D2 dissection