Oral antibiotics combined with mechanical bowel preparation reduces the risk of surgical site infections in minimally invasive colorectal cancer surgery

Purpose Colorectal surgeries are associated with high rates of surgical site infection (SSI), which significantly impact postoperative recovery and outcomes. Use of preventive measures, such as mechanical bowel preparation (MBP) and preoperative oral antibiotics (POA), is widely debated. This study investigated the effectiveness of POA plus MBP before elective minimally invasive colorectal cancer surgery. Methods This study retrospectively analyzed 1,506 patients who underwent elective minimally invasive colorectal cancer surgery between January 2020 and December 2023 to evaluate the effectiveness of MBP plus POA in preventing SSIs and other postoperative complications. Patients were divided into MBP alone (n = 811) and POA + MBP (n = 695) groups. Results Overall SSI rates were significantly lower in the POA + MBP group than in the MBP alone group (11.6% vs. 5.5%, p = 0.008), with significant reductions in grade 1–2 SSIs. POA + MBP was particularly effective in patients undergoing colon cancer surgery. In this subgroup, POA + MBP was associated with a 5.6% lower rate of SSIs than MBP alone, with no difference in anastomosis leakage rates between regimens. In patients undergoing rectal cancer surgery, POA + MBP was associated with a significantly higher anastomosis leakage rate (6.9% vs. 2.2%, p  = 0.016), with no difference in SSI rates between regimens. Multivariable analysis confirmed that MBP alone was a risk factor for SSIs (odds ratio, 1.5; 95% confidence interval, 1.13–2.18; p  = 0.007). Conclusion This study highlights the differential effects of POA + MBP in minimally invasive surgery for colon versus rectal cancer and underscores the need for further investigations to determine the optimal bowel preparation regimen for specific surgical sites.