The ypT category does not impact overall survival in node negative gastric cancer

Background: Although the eighth-edition American Joint Committee on Cancer (AJCC) gastric cancer staging system created ypTNM staging for patients who underwent preoperative therapy, the ideal ypTNM grouping is unknown. We sought to investigate risk factors for OS in ypT0-3N0M0 gastric cancer. Methods: From an institutional database of The University of Texas MD Anderson Cancer Center and the National Cancer Database (NCDB), we identified patients with ypT0-3N0M0 gastric adenocarcinoma who underwent R0 gastrectomy after chemotherapy or chemoradiation during 1995-2015 (MD Anderson) or 2006-2014 (NCDB). Results: The study included 175 MD Anderson and 3200 NCDB patients. By multivariable analysis, ypT category was not associated with OS (hazard ratio [HR] for ypT3 vs ypT1: MD Anderson, 0.83 [95% CI, 0.36-1.92], P = 0.669; NCDB, 0.96 [95% CI, 0.85-1.08], P = 0.472). cN-positive disease was not associated with OS in the MD Anderson cohort (HR, 0.96 [95% CI, 0.55-1.67]; P = 0.873) but was weakly associated with shorter OS in the NCDB cohort (HR, 1.11 [95% CI, 1.01-1.21]; P = 0.031). Conclusions: The ypT category does not impact OS in ypT0-3N0M0 gastric cancer. The impact of cN status on OS appeared limited. These findings should be considered in future systems of post-neoadjuvant pathologic staging.