Inflammatory cell ratios predict major septic complications following rectal cancer surgery.

INTRODUCTION: The inflammatory response is known to have an important role in tumourigenesis and the response to treatment. Previous studies have demonstrated that inflammatory cell ratios such as the neutrophil-to-lymphocyte ratio (NLR) can predict survival and recurrence following surgery for various cancers. The objective of this study was to demonstrate if pre-operative NLR has a role in predicting post-operative septic complications in patients undergoing rectal cancer surgery.

METHODOLOGY: Consecutive patients undergoing scheduled resection for rectal cancer in a tertiary centre from July 2007 to Dec 2015 were included. Data was gathered from a prospectively held database of rectal cancer. Normally distributed data were compared with paired t tests (mean ± standard error in the mean (SEM)), and proportions were compared with Fisher's exact test. A p value of < 0.05 was considered statistically significant.

RESULTS: Three hundred fourteen patients were identified in this study. Sixty nine (22.0%) patients had a major septic complication following surgery for rectal cancer, which was associated with a poor survival outcome (p < 0.01) Both pre and post-operative NLR and PLR (platelet lymphocyte ratio) were associated with post-operative septic complications (both p < 0.01). A pre-operative NLR threshold level of 4 was chosen from ROC analysis, and this provided a relatively specific test to predict post-operative septic complications in these patients (specificity = 83.7%, negative predictive value (NPV) = 74.8%).

DISCUSSION: In this study, the pre-operative NLR and PLR were both predictive of major post-operative septic complications. A pre-operative NLR of less than 4 was strongly negative predictor of post-operative complications in rectal cancer surgery. It can be regarded as a predictive and prognostic factor for these patients.