Preoperative radiation therapy in the surgical management of gastric and junctional adenocarcinoma: Should lymph node retrieval guidelines be altered?

Background Although surgery remains the cornerstone of gastric cancer therapy, the use of radiation therapy (RT) is increasingly being employed to optimize outcomes. We sought to assess outcomes following use of RT for the treatment of gastric adenocarcinoma. Methods Using the National Cancer Data Base (NCDB) from 1998 to 2012, all patients with resected gastric adenocarcinoma were identified. Patients were stratified into four groups based on preoperative therapy: RT alone, chemotherapy only, chemoradiotherapy (CRT), and no preoperative therapy. Overall survival was estimated using multivariate Cox proportional hazards model. Adjusted secondary outcomes include margin positivity, lymph node harvest, LOS, 30‐day readmission and mortality. Results A total of 10 019 patients met study criteria. In the unadjusted analysis, patients undergoing CRT compared to chemotherapy alone had fewer positive margins (7.9% vs 15.9%; P  < 0.001), increased negative LNs (54.6% vs 37.7%; P  < 0.001) with reduced LN retrieval (mean: 13.5 vs 19.6; P  < 0.01). After multivariate adjustment, there was no survival benefit to any preoperative therapy; however, preoperative RT/CRT remained associated with decreased LN retrieval. Conclusions The results support previous reports on preoperative RT resulting in decreased margin positivity. This study highlights the need to reconsider practice guidelines regarding appropriate lymphadenectomy in the setting of preoperative RT given reduced LN retrieval.