Diagnostic accuracy of C-reactive protein in detecting anastomotic leakage after minimally invasive rectal cancer surgery

Background: C-reactive protein’s (CRP) diagnostic utility for early detection of anastomotic leakage is based on heterogeneous patient groups, including different pathologies and surgical approaches, without accounting for the presence of faecal diversion. This study assessed the diagnostic accuracy of CRP in detecting anastomotic leakage after minimally invasive total mesorectal excision (TME) for rectal cancer, stratified by the presence or absence of a primary diverting stoma. Methods: Patients from 11 high-volume centers in the Netherlands who underwent minimally invasive TME for rectal cancer between 2015 and 2021 were included. CRP levels were analyzed from postoperative days 1–4, and diagnostic accuracy was assessed using receiver operating characteristic analysis. Subgroup analyses were performed for patients with and without a primary diverting stoma. Results: A total of 1418 patients were included, with anastomotic leakage occurring in 232 (16.4%). In patients without a stoma, the highest diagnostic accuracy was on day 4 at a cut-off of 104.5 mg/L, with sensitivity of 84.1%, specificity of 71.1%, PPV of 38.1%, and NPV of 95.5% (AUC = 0.83, P < 0.001). In patients with a stoma, diagnostic accuracy was lower, with maximum performance at a cut-off of 132.5 mg/L on day 4 (sensitivity 57.6%, specificity 78.7%, PPV 36.5%, NPV 89.7%, AUC = 0.71, P < 0.001). The difference in AUC was significant (P = 0.018). Conclusion: CRP has poor diagnostic accuracy for detecting anastomotic leakage in patients with a primary diverting stoma after minimally invasive rectal cancer surgery. Additional diagnostic tests should be considered for this group to allow for early detection of anastomotic leaks.