Effect of lymphocyte-to-monocyte ratio on prognosis in obstructive colorectal cancer patients with colonic stent: a Japanese retrospective multicenter study

Abstract

Background The prognostic value of the lymphocyte-to-monocyte ratio (LMR) has been reported for various cancers, including colorectal cancer (CRC). Insertion of self-expanding metallic stents (SEMS) is considered effective for patients with surgically indicated obstructive CRC, but LMR can vary depending on factors such as inflammation associated with stent dilation, improvement of obstructive colitis and nutritional status. LMR may thus change at the time of evaluation. However, the usefulness of LMR in CRC patients requiring SEMS insertion and the optimal timing for measuring LMR remain unclear. This study investigated the relationship between pre-stent LMR and long-term prognosis in patients who underwent bridge to surgery (BTS) for obstructive CRC with SEMS insertion. Methods Participants comprised 175 patients with pathological stage 2 or 3 disease who underwent BTS for obstructive CRC with SEMS insertion. Patients were divided into two groups according to pre-stent LMR, as follows: low pre-stent LMR group (pre-LMR-L, n = 87) and high pre-stent LMR group (pre-LMR-H, n = 83). Results Median follow-up was 33 months (range, 1–77 months). Five-year relapse-free survival (RFS) only differed significantly for pre-LMR (pre-LMR-L: 39.9% vs. pre-LMR-H: 63.6%; p = 0.015). Pre-LMR represented a prognostic factor for RFS in both univariate (hazard ratio [HR] 1.845, 95% confidence interval [CI] 1.125–3.026; p = 0.015) and multivariate analyses (HR 2.052, 95%CI 1.242–3.389; p = 0.005). Pre-LMR was not a prognostic factor for overall survival in univariate analysis (HR 1.721, 95%CI 0.878–3.374; p = 0.114). Conclusions Pre-LMR-L represents a prognostic factor for postoperative recurrence in patients who undergo BTS for obstructive CRC with SEMS insertion.