Is It Time to Abandon the 5-cm Margin Rule During Resection of Distal Gastric Adenocarcinoma? A Multi-Institution Study of the U.S. Gastric Cancer Collaborative

Background A proximal margin distance of 5 cm is advocated for resection of gastric adenocarcinoma (GAC). We assessed the prognostic value of proximal margin (PM) distance on survival outcomes after resection of distal GAC. Methods All patients who underwent resection of distal GAC (antrum/body) from 2000 to 2012 at seven institutions of the U.S. Gastric Cancer Collaborative were included. Patients with positive distal margins or macroscopic residual disease were excluded. The prognostic value of PM distance (assessed in 0.5-cm increments) on overall (OS) and recurrence-free survival (RFS) was assessed by Kaplan–Meier and multivariate regression analysis. Results A total of 465 patients underwent resection of distal GAC. Of these, 435 had R0 resections; 30 patients had a positive PM. 143 patients had stage I, and 322 had stage II–III tumors. Median follow-up was 44 months. Average PM distance was 4.8 cm. Median OS for patients with PM of 3.1–5.0 cm ( n = 110) was superior to patients with PM ≤ 3.0 cm ( n = 176) (48.1 vs. 29.3 months; p = 0.01), while a margin >5.0 cm ( n = 179) offered equivalent survival to PM 3.1–5.0 cm (50.6 months, p = 0.72). The prognostic value of margin distance was stage specific. On multivariate analysis of stage I patients, PM 3.1–5.0 cm remained associated with improved OS [hazard ratio (HR), 0.16; 95 % confidence interval (95 % CI), 0.04–0.60; p = 0.01]. In stage II–III, neither PM 3.1–5.0 cm nor PM > 5.0 cm was significantly associated with OS; OS was dictated by T stage and nodal involvement. Conclusions The prognostic value of proximal margin distance after resection of distal gastric cancer appears stage specific. In stage I, a 3.1- to 5.0-cm proximal margin is associated with the same improved OS as a > 5.0-cm margin. In stage II–III disease, other adverse pathologic factors more strongly impact survival than proximal margin distance.