To verify whether procalcitonin (PCT) and C-reactive protein (CRP) can be used as an early predictor of anastomotic leakage (AL) and determine the optimal cut-off value, so as to provide evidence for early identification of AL after colorectal cancer surgery.

From January 2013 to April 2017, four hundred and eight cases undergoing colorectal cancer operation in Anshan Iron and Steel Group General Hospital were selected. The concentration of PCT, CRP and the white cell count (WBC) were detected 3, 5 d after operation (POD). The methods of operation, AL and other complications after operation were recorded. The differences of PCT, CRP and WBC levels among the AL group, the non-AL group and the non-complication group were compared on 3rd, 5th POD. According to the ROC curve, the prediction accuracy of PCT, CRP and WBC for AL were compared, and their sensitivity (SE), specificity (SP), joint sensitivity, joint specificity, negative predictive value (NPV), positive predictive value (PPV), the best critical value were also calculated.

AL occurred in 19 cases, and the PCT and CRP values of the AL group were higher than the other two groups (P<0.05). The AUC of PCT and CRP was 0.773 and 0.839 on 3rd POD, and 0.893 and 0.863 on 5th POD, respectively. The prediction accuracy of the 5th POD was better than that of the 3rd POD for AL. The optimal cut-off value of PCT on 5th POD was 2.15 g/L, and NPV, PPV, SE, and SP of AL were 96.4%, 32.1%, 84.2% and 90.7%, respectively. The optimal cut-off value of CRP on 5th POD was 129.5 mg/L, NPV, PPV, SE, and SP of AL were 95.7%, 19.6%, 94.7% and 77.6%, respectively. A joint-detection of PCT and CRP could provide higher SE and SP up to 100.0% and 70.4%, respectively.

PCT and CRP are valuable indicators for early diagnosis of AL after colorectal surgery. Combined detection of PCT and CRP on 5th POD may be more conducive to the prediction of AL.