Comparisons of remnant primary, residual, and recurrent gastric cancer and applicability of the 8th AJCC TNM classification for remnant gastric cancer staging.

ABSTRACT

BACKGROUND: Because there is no well-established postoperative staging system for patients with remnant gastric cancer (RGC), we compared the overall survival of patients categorized with the 8th AJCC TNM staging system. METHOD: A total of 391 patients underwent surgery for RGC at our institution between 1996 and 2019. Among them, 201 patients received their first surgery at our institution and 190 received primary surgery elsewhere. We retrospectively reviewed their medical records and classified each according to Kaminishi's classification and the 8th AJCC TNM staging system for comparison and analysis. RESULTS: All 201 patients who underwent their first operation at our institution for malignancy were classified as primary (n = 41, 20.4%), residual (n = 103, 51.2%), and recurrent (n = 57, 28.4%) RGC. The 5-year overall survival (OS) rates for the primary, residual, and recurrent RGC groups were 78.1%, 73.8% and 56.0%, respectively (p = 0.004). In a multivariate analysis, RGC classification was an independent prognostic factor along with the TNM staging system (p = 0.001). However, there was no significant difference in OS between the three groups of the same TNM stage. In addition, the OS of each stage related to primary cancer was not significantly different from the OS of RGC patients classified in TNM staging. CONCLUSION: The RGC classification system we used may reflect the comprehensive aspects of previous disease states and predict the prognosis of patients with gastric cancer. In addition, the 8th AJCC TNM classification is a practical and applicable staging system for RGC.