Safety and prognostic impact of prophylactic laparoscopic superior mesenteric vein (No. 14v) lymph node dissection for lower-third gastric cancer: a propensity score-matched case-control study

Aim To investigate oncologic efficacy of prophylactic laparoscopic superior mesenteric vein (No. 14v) lymph node (LN) dissection for lower-third gastric cancer (LTGC). Methods We retrospectively collected data from 757 patients who underwent laparoscopic-assisted distal gastrectomy for LTGC. Of these patients, 102 underwent 14v LN dissection (14vD+ group), and the remaining 655 patients did not undergo 14v LN dissection (14vD-group). The outcomes were compared using a 1: 1 propensity score matching method. Results After matching, 93 patients from the 14vD+ group and 93 patients from the 14vD-group with similar clinicopathological characteristics were compared. Before matching, the overall survival (OS) was similar between the two groups (P = 0.742). After matching, the OS was greater in the 14vD+ group (P = 0.025). The status of 14v dissection was not a significant prognostic factor in the survival analyses, both before and after matching. However, a stratified analysis according to the independent factors in the OS showed that the OS in the 14vD+ group was higher than that in the 14vD-group for cT2-3 patients after matching. The forest plot of OS showed that after matching the 14vD+ group had a significantly higher 3-year OS rate than the 14vD-group in cT2-3 patients. The distribution of the therapeutic index demonstrated that the index of 14v LN was similar to those of Nos. 1, 7, 8a, 9, and 11p after matching. Conclusions Adding laparoscopic 14v dissection for laparoscopic-assisted radical distal gastrectomy was safe and might improve the OS for clinically advanced LTGC without serosal invasion.