Inflammatory stress and recovery after colorectal cancer surgery: The predictive role of early C-reactive protein across open, laparoscopic, and robotic approaches

C-reactive protein (CRP) is a well-established biomarker of surgical stress and postoperative inflammation. This study aimed to compare the postoperative inflammatory response and recovery after colorectal cancer surgery via open, laparoscopic, or robotic approaches and to assess the predictive value of early CRP levels for complications and prolonged hospital stays. A retrospective analysis was conducted on 291 patients who underwent elective colorectal cancer resection between January 2021 and July 2025 at Policlinico Umberto I, Italy . CRP values were measured on postoperative days (PODs) 1, 3, and 5. Receiver operating characteristic curve analysis was performed, and the area under the curve (AUC) was calculated to assess the accuracy of the CRP level in predicting postoperative complications and prolonged length of stay (LOS ≥7 days). Overall, 46 patients (15.8%) experienced complications. The complication rates were 21.1% after open surgery, 13.5% after laparoscopic surgery, and 15.2% after robotic surgery ( p = 0.42). CRP levels decreased from POD 1 to POD 5 in open surgery and laparoscopic surgery groups, whereas in the robotic surgery group they increased from POD 1 to POD 3 and then decreased by POD 5; CRP levels differed among the approaches at POD 1, POD 3, and POD 5 ( p < 0.05). The POD 1 CRP showed the best (yet modest) discrimination for complications (AUC 0.687), with high sensitivity (0.92) and low specificity (0.47), supporting its use primarily to rule out complications. Later, the CRP values and dynamic indices (DeltaCRP5-3 and DeltaCRP5-1) showed limited accuracy, particularly for prolonged LOS (AUC <= 0.60). Early postoperative CRP (POD1) may help identify patients at increased risk of postoperative complications after colorectal resection, although its discriminatory ability is modest. The high sensitivity and low specificity suggest a role in ruling out, rather than confirming, complications. Although the CRP level differed significantly among surgical approaches at PODs 1, 3, and 5, postoperative outcomes were comparable among the groups.