Neutrophil-to-lymphocyte ratio as an early predictor of anastomotic leakage after rectal cancer surgery.

Abstract

Anastomotic leakage after rectal cancer surgery is a severe complication associated with increased morbidity and mortality. Current diagnostic methods lack sensitivity and timeliness. This study evaluated the neutrophil-to-lymphocyte ratio as an early predictive marker for anastomotic leakage. A prospective cohort of 763 patients with rectal cancer undergoing low anterior resection was analyzed. Neutrophil-to-lymphocyte ratio was calculated preoperatively and on postoperative days 1, 3, 5, and 7. Anastomotic leakage was defined on the basis of clinical, radiologic, or surgical evidence. Statistical analyses included receiver operating characteristic curves to determine neutrophil-to-lymphocyte ratio cutoff values, logistic regression, and comparisons between anastomotic leakage and nonanastomotic leakage groups. Anastomotic leakage occurred in 6.9% (53/763) of patients, with 37 cases diagnosed between postoperative days 7 and 16. Neutrophil-to-lymphocyte ratio values in patients with anastomotic leakage were significantly elevated on postoperative day 3 (median 10.3 vs 7.5, P < .05), postoperative day 5 (8.9 vs 4.9), and postoperative day 7 (6.8 vs 4.5). Receiver operating characteristic analysis identified optimal neutrophil-to-lymphocyte ratio cutoffs: 8.9 on postoperative day 3 (under the receiver operating characteristic curve, 0.708; sensitivity, 73.6%; specificity, 73.2%) and 7.3 on postoperative day 5 (under the receiver operating characteristic curve, 0.757; sensitivity, 66.0%; specificity, 83.4%). For delayed leaks (after postoperative day 7), a postoperative day 7 neutrophil-to-lymphocyte ratio cutoff of 6.1 demonstrated under the receiver operating characteristic curve of 0.750 (sensitivity, 62.3%; specificity, 81.7%). Patients requiring reoperation had a greater postoperative day 3 neutrophil-to-lymphocyte ratio (11.3 vs 9.4, P = .009), and fatal cases of anastomotic leakage exhibited an extreme neutrophil-to-lymphocyte ratio elevation (22.9-29.5). The neutrophil-to-lymphocyte ratio is a cost-effective, noninvasive biomarker that enhances early anastomotic leakage diagnosis, potentially improving clinical outcomes.