Diagnostic performance of procalcitonin for detecting anastomotic leak in older adults with colorectal cancer: A delayed type cross-sectional study

Background: The utility of procalcitonin for detecting anastomotic leaks after colorectal surgery in older adults has not been well documented. As the immune system undergoes changes with age, procalcitonin levels may differ at baseline, and its diagnostic performance could vary when an anastomotic leak occurs after colorectal surgery in older adult patients with cancer. The aim of this study is to evaluate the diagnostic performance of procalcitonin on postoperative day 3 for detecting anastomotic leaks in older adults with colorectal cancer. Methods: We conducted a diagnostic test study on the basis of a delayed-type cross-sectional design in older adults (≥65 years old) with colorectal cancer. Postoperative day 3 procalcitonin levels were tested. The reference standard was anastomotic leak. We calculated the receiver operating characteristic curve and its area under the curve. Results: The incidence of anastomotic leak was 7.7%. On postoperative day 3, the receiver operating characteristic demonstrated an area under the curve of 0.68 (95% confidence interval, 0.58–0.78) for the prediction of an anastomotic leak using procalcitonin levels. The cutoff point with the greatest diagnostic performance, according to the Youden index, was 0.61 ng/mL, with a sensitivity of 0.69, specificity of 0.62, a positive likelihood ratio of 1.86, and a negative likelihood ratio of 0.48 for predicting an anastomotic leak. The area under the curve was 0.78 when ileostomies were excluded and 0.81 when evaluating grade C leaks. Conclusion: Our study reveals that procalcitonin levels on postoperative day 3 are a poor diagnostic marker for identifying anastomotic leaks in older adults with colorectal cancer, with an improvement in performance for the grade C anastomotic leak subgroup.