Inflammatory cell ratios predict major septic complications following rectal cancer surgery

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.

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.

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%).

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.