Characterizing Patients with ypT0N1 Gastric Adenocarcinoma Within the AJCC Staging System.

Introduction: The standard of care for gastric cancer in the United States involves perioperative chemotherapy. While most post-therapy pathologic staging results are concordant (i.e. ypTN or ypT0N0), patients occasionally display discordant results, such as ypT0N1. Herein, we characterized the survival of patients with ypT0N1 staging to better determine their categorization within the American Joint committee on Cancer (AJCC) staging system.

Methods: Using the National Cancer Database (NCDB), we queried all patients diagnosed with gastric adenocarcinoma from 2004 to 2021 who received neoadjuvant chemotherapy. Patients were stratified by their ypTNM stage: (1) ypT0N0; (2) ypT+N0; (3) ypT+N1; and (4) ypT0N1. Multivariable Cox proportional hazard regression was used to assess 5- and 10-year survival between ypTNM stages.

Results: A total of 28,985 patients received neoadjuvant chemotherapy, of whom 2378 (8.2%) had ypT0N0, 9402 (32.4%) had ypT+N0, 5339 (18.4%) had ypT+N1, and 318 (1.1%) had ypT0N1 staging. Overall, patients had a median age of 64 years, with the majority being male (74.9%) or White (82.2%). Additionally, 50.2% received care from an academic center, and 53.3% received neoadjuvant chemotherapy and radiotherapy. On multivariable analysis, patients with ypT0N1 had a 105% higher risk for mortality within 5 years (adjusted hazards ratio [aHR] 2.05, 95% confidence interval [CI] 1.69-2.50) and 86% increased risk within 10 years (aHR 1.86, 95% CI 1.54-2.23) when compared with ypT0N0.

Conclusion: Patients with stage ypT0N1 disease have worse 5- and 10-year outcomes than those with node-negative disease. Thus, their survival pattern most closely matches patients with ypstage IIB and III disease.