Neutrophil-to-lymphocyte ratio as a predictor of postoperative morbidity in patients with distal cholangiocarcinoma

Systemic inflammatory-, immunological- and nutritional-based indices, such as the neutrophil-to-lymphocyte ratio (NLR), the prognostic nutritional index (PNI) and the Glasgow prognostic score (GPS), are drawing considerable research attention to predict the long-term prognosis of many types of cancer. Recently, these parameters have also been reported to be useful in predicting postoperative morbidity in several fields, including colorectal and otolaryngological cancer. However, while distal cholangiocarcinoma exhibits a high morbidity rate, its risk factors of morbidity have not yet been established. This is because previous studies have analyzed distal cholangiocarcinoma as periampullary tumors combined with pancreatic head cancer. Therefore, the aim of the present study was to investigate the application of the NLR, the PNI and the GPS in evaluating risk factors for postoperative morbidity in patients with distal cholangiocellular or ampullary carcinoma. Eighty-four patients who underwent pancreaticoduodenectomy (PD) for distal cholangiocellular or ampullary carcinoma at the Department of Surgery in Kitasato University Hospital between 2008 and 2016 were enrolled. Associations between perioperative characteristics (NLR, PNI and GPS) and postoperative complications (Clavien-Dindo classification grade III or higher) were retrospectively analyzed. In the univariate analysis, neutrophil and lymphocyte counts, body mass index (BMI) and the NLR were associated with postoperative complications (P<0.05). In the multivariate analysis, BMI [>23.0 kg/m(2); odds ratio (OR): 3.80, 95.0% confidence interval (CI): 1.35–11.83; P=0.011] and the NLR (>2.0; OR: 6.77, 95.0% CI: 2.44–21.13; P<0.001) were independent risk factors for postoperative complications. BMI and the NLR are valuable predictors of postoperative morbidity following PD in patients with distal cholangiocarcinoma. It would be beneficial to determine treatment strategies for distal cholangiocarcinoma based on the NLR to reduce postoperative complications.