The role of preoperative mechanical bowel preparation and oral antibiotics in prevention of anastomotic leakage following restorative resection for primary rectal cancer - a systematic review and meta-analysis.

Purpose: Anastomotic leakage after colorectal cancer resection is a feared postoperative complication seen among up till 10-20% of patients, with a higher risk following rectal resection than colon resection. Recent studies suggest that the combined use of preoperative mechanical bowel preparation and oral antibiotics may have a preventive effect on anastomotic leakage. This systematic review aims to explore the association between preoperative mechanical bowel preparation combined with oral antibiotics and the risk of anastomotic leakage following restorative resection for primary rectal cancer.

Methods: Three databases were systematically searched in February 2022. Studies reporting anastomotic leakage rate in patients, who received mechanical bowel preparation and oral antibiotics before elective restorative resection for primary rectal cancer, were included. A meta-analysis was conducted based on the risk ratios of anastomotic leakage.

Results: Among 839 studies, 5 studies met the eligibility criteria. The median number of patients were 6111 (80-29,739). The combination of preoperative mechanical bowel preparation and oral antibiotics was associated with a decreased risk of anastomotic leakage (risk ratio = 0.52 (95% confidence interval 0.39-0.69), p-value < 0.001). Limitations included a low number of studies, small sample sizes and the studies being rather heterogenous.

Conclusion: This systematic review and meta-analysis found that the use of mechanical bowel preparation and oral antibiotics is associated with a decreased risk of anastomotic leakage among patients undergoing restorative resection for primary rectal cancer. The limitations of the review should be taken into consideration when interpreting the results.