Background and aim: Postoperative infectious complications (POI), which can increase length of hospital stay, medical cost, and worsen overall survival, are a concern in minimally invasive colorectal cancer (CRC) surgeries. Recent reports showed that relatively new inflammation-based score, lymphocyte-to-monocyte ratio (LMR) is an independent predictor of long-term outcomes after CRC surgeries. In this study, LMR was evaluated as a predictor of short-term postoperative outcomes.
Patients and methods: This was a single-institutional retrospective study of 211 consecutive patients who had undergone laparoscopic CRC surgery with primary tumor resection from January 2014 to August 2015 at Nippon Medical School Chiba Hokusoh Hospital. The patients were divided into two groups (no POI; n = 176 and POI; n = 35). The associations between inflammation-based scores, namely neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and LMR, and the occurrence of POI were investigated. Receiving operator characteristic curve analysis was used to determine the cutoff point of preoperative LMR.
Results: Low LMR (cut-off 3.46), long operative time, and smoking were found to be independent predictors of POI in a multivariate analysis (LMR: Odds ratio 5.61, 95% confidence interval 1.98-15.9, P = 0.001). Patients with low LMR also appeared to have more advanced and aggressive tumours.
Conclusion: This is the first study to report that the lower LMR is a predictive factor of POI after laparoscopic CRC surgery, and it may provide additional information for treatment decisions to prevent POI.
Keywords: Colorectal cancer; Inflammation-based score; Laparoscopic surgery; Lymphocyte-to-monocyte ratio; Postoperative infection.