The Prognostic Impact of the Lymphocyte-to-Monocyte Ratio in Resected Pancreatic Head Adenocarcinoma

Objective: Although the prognostic significance of systematic inflammation-based scores, such as the neutrophil-to-lymphocyte ratio (NLR), the platelet-to-lymphocyte ratio (PLR), and the prognostic nutritional index (PNI), has been explored in pancreatic cancers, few reports have investigated the lymphocyte-to-monocyte ratio (LMR). We aimed to retrospectively investigate the prognostic value of the preoperative LMR in patients with resectable pancreatic head cancer (PHC). Methods: From 2005 to 2016, 165 patients underwent pancreatoduodenectomy for PHC. All samples of peripheral blood were collected within 2 weeks prior to surgery. The best cutoff values of the LMR for predicting survival were determined by using a minimum p value approach (cut-off value: 2.8). The clinicopathological features of LMR <2.8 (n = 25) and >= 2.8 (n = 140) were compared. Results: Patients with LMR >= 2.8 showed significantly lower NLR and PLR, and significantly higher PNI. Levels of CEA and CA19-9 were similar, and the pathological findings were comparable between the groups. The overall survival of patients with LMR >= 2.8 (66.2% at 1 year) was superior to that of patients with LMR <2.8 (36.1% at 1 year, p = 0.015). Multivariate analysis identified LMR <2.8 (hazard ratio 1.72, 95% CI 1.02-2.89, p = 0.042), lymphatic and venous invasion and positive surgical margin as independent prognostic factors. Conclusions: LMR may carry important prognostic information for patients with resectable PHC. Preoperative LMR may be considered for use in risk stratification for individual patients with PHC.