To explore the clinical value of procalcitonin (PCT), C-reactive protein (CRP) and the white cell count (WBC) in early identification of anastomotic leakage after laparoscopic anterior rectal resection, and to construct a nomogram to predict the individual risk of anastomotic leakage.

We conducted a prospective study including 173 patients with rectal cancer who underwent laparoscopic anterior rectal resection in the General Surgery Center of the Affiliated Hospital of Qingdao University from January 2017 to June 2019. The primary endpoint investigated was anastomotic leakage. Kruskall-Wallis test was used to compare the measurement data, χ² test was used to compare the counting data. ROC curve was drawn to compare the prediction accuracy of PCT, CRP, WBC to anastomotic leakage. R software was used to construct the nomogram based on multivariate Logistic regression analysis of anastomotic leakage. Calibration curve was drawn to analysis the calibration degree of the model. Stata software was used to draw the ROC curve to analyze the discrimination degree of the model.

A total of 173 patients were included. anastomotic leakage was detected in 13 patients (7.5%). PCT and CRP had the best predictive efficacy on postoperative day 3 (POD3), with AUC of 0.937 (95%CI: 0.900~0.985) and 0.909 (95%CI: 0.874~0.968), respectively, and the negative predictive values obtained from the best cutoff values of 0.75 ng/mL and 84.05 mg/L were 97.6% and 96.6%, respectively. The predictive accuracy of the combined detection of PCT and CRP for anastomotic leakage on POD3 and POD5 were better than the single index test (AUC: 0.964 vs. 0.956). A nomogram for predicting anastomotic leakage by PCT, CRP and WBC on POD3 was constructed. The calibration curve showed that the model had a good calibration, and the average absolute error between the actual risk and the predicted risk was 0.042. ROC curve showed that the model had a good degree of differentiation, AUC was 0.975 (95%CI: 0.947~1), the specificity and sensitivity of the model are 100.0% and 87.36%, respectively.

PCT and CRP are reliable indicators for early identification of anastomotic leakage and safe discharge after laparoscopic anterior rectal resection. The nomogram constructed by PCT, CRP and WBC on POD3 may effectively guide the individual prediction of anastomotic leakage.