Prognostic impact of a microscopic positive margin in patients undergoing gastrectomy for gastric cancer: a propensity score‑matched analysis of a multi‑institutional dataset.

Abstract

We analyzed the effect of a microscopic positive margin on survival outcomes after gastrectomy for gastric cancer METHODS: We analyzed a multi-institutional dataset to study patients who underwent gastrectomy with curative intent between 2010 and 2014. We used propensity score matching to strictly balance the patients' oncological features, backgrounds, and postoperative treatment to compare the survival outcomes of those with microscopic positive margins and those with negative margins. Among 3029 patients, 32 (1.1%) had positive margins. After matching, we enrolled 128 patients in this retrospective analysis: 32 with a positive margin and 96 with a negative margin. The recurrence-free survival of the positive-margin group was significantly shorter than that of the negative-margin group (hazard ratio [HR], 1.62, 95% confidence interval, 1.00-2.63, p = 0.0485). Consistent results were observed for patients with pStages I-III disease (HR, 1.65, p = 0.0835), whereas the survival curves overlapped in those with pStage IV disease (HR, 1.29, p = 0.5934). The prevalence of overall recurrence in the positive-margin group was higher than that in the negative-margin group (75% vs 58%, p = 0.0917). This trend was consistent with locoregional recurrence (9% vs 3%) and distant recurrence (69% vs 55%). The survival of patients after curative gastrectomy for gastric cancer was worse in those with microscopic positive margins than in those with negative margins.