Abstract
BACKGROUND: The American Joint Committee on Cancer's 8th edition introduced ypStage, a separate staging system for patients with gastric cancer having undergone preoperative therapy. Overall, ypN0 patients have better survival outcomes than ypN+ patients. However, whether patients with cN+/ypN0 disease ("downstaged N0") and those with cN0/ypN0 disease ("natural N0") have similar survival is unknown. METHODS: An institutional database was reviewed to identify gastric adenocarcinoma patients who underwent potentially curative R0 resection after induction chemotherapy or chemoradiation. Patients were categorized into three groups based on nodal status: cN0/ypN0, cN+/ypN0, and ypN+. Univariable and multivariable Cox regression models were used to identify clinicopathologic factors associated with overall survival (OS). RESULTS: We identified 316 patients who met the study criteria. Ninety-four patients (30%) had cN0/ypN0 disease, 93 (29%) had cN+/ypN0 disease, and 129 (41%) had ypN+ disease. The median OS was 7.7 years, and the 5-year OS was 60.3%. In the multivariate analysis, OS did not differ between the cN0/ypN0 and cN+/ypN0 patients (hazard ratio, 0.90 [95% CI 0.54-1.48]; p = 0.666), but it was shorter in ypN+ patients (hazard ratio, 1.82 [95% CI 1.15-2.87]; p = 0.01). CONCLUSIONS: In gastric cancer patients who underwent preoperative therapy, we found similar OS in cN0/ypN0 and cN+/ypN0 patients. Because ypN+ patients had poor OS, achieving ypN0 status is an important hallmark demonstrating the effectiveness of preoperative therapy for gastric cancer.