Microscopic Positive Margins in Gastric Adenocarcinoma Following Oncological Resection: Prognostic Factors and Long-Term Survival.

Background: In the context of gastric cancer, surgical resection stands as the sole curative treatment. Central to influencing overall survival are the resection margins. This research aims to identify the factors influential in determining microscopically positive resection margins (R1) and to evaluate overall survival.

Methods: Our study encompassed 549 patients diagnosed with adenocarcinoma of the stomach who underwent curative-intent surgery between January 2011 and December 2021 in our Surgery Department. We investigated the incidence of positive margins (R1) and their impact on survival rates, as well as the determinants of R1. The standardization of R1 involved ensuring a margin distance of less than 1 mm from the tumor line to the margin.

Results: The incidence of R1 margins was 13.29% (73 patients). Among these, proximal R1 margins were observed in 29 patients (39.72%), while 49 cases (67.12%) presented circumferentially positive margins, with 20 cases (27.39%) exhibiting distally positive margins. Nineteen patients (26.02%) had two R1 margins, and 3 patients had all resection margins microscopically positive (4.10%). Factors such as tumor dimension, invasion of other organs, pT stage, pN stage, pL1 stage, pV1 stage, pPn stage, Lauren type, and tumoral grading demonstrated significance (p < 0.01) in the occurrence of positive R1 margins.

Conclusion: Tumor dimension, invasion of other organs, pT stage, pN stage, pL1 stage, pV1 stage, pPn stage, Lauren type, and tumoral grading could be regarded as factors for predicting microscopically positive margins. Moreover, positive resection margins have a detrimental impact on overall survival.