Diagnostic accuracy of C-reactive protein and procalcitonin in the early diagnosis of infections after laparoscopic rectal cancer surgery

Background We aimed to examine the diagnostic accuracy of postoperative procalcitonin (PCT) and C-reactive protein (CRP) in the detection of infectious complications in patients after laparoscopic rectal cancer surgery, as opposed to all colorectal surgery. Methods Between December 2018 and December 2020, 204 patients who underwent laparoscopic rectal cancer surgery were enrolled retrospectively. The PCT, CRP and white blood cell (WBC) count were measured before surgery and on postoperative days (PODs) 3 and 5. Diagnostic accuracy was determined by the area under the receiver operating characteristic curve (AUC). Net Reclassification Index (NRI) was used to calculate the ability to correct reclassification. Results Infectious complications occurred in 36 patients (17.6%), including 17 cases of anastomotic leakage (AL) (8.3%). The AUCs of PCT and CRP in predicting infectious complications on POD 3 were 0.690 and 0.731, respectively, which were better than those on POD 5 (AUC 0.666 and 0.697, respectively). PCT with an optimal cutoff value of 1.10 ng/mL (AUC 0.792, specificity 78.6%, negative predictive value [NPV] 96.6%), CRP with an optimal cutoff value of 109.5 mg/L (AUC 0.760, specificity 78.6%, NPV 96.1%) on POD 3 had superior diagnostic accuracy in predicting AL, both better than WBC (AUC 0.627). The AUC of combining PCT and CRP on POD 3 in predicting AL was 0.851, with a specificity of 79.7% and NPV of 97.4%, and the NRI was estimated to be 7.0%. Conclusions Both PCT and CRP on POD 3 are excellent negative predictors for early monitoring of infectious complications, especially AL, in patients undergoing laparoscopic rectal cancer surgery.