Diverting stomas reduce reoperation rates for anastomotic leak but not overall reoperation rates within 30 days after anterior rectal resection: a national cohort study

PURPOSE: A diverting stoma is commonly formed to reduce the rate of anastomotic leak following anterior resection with anastomosis, although some studies question this strategy. The aim of this study was to assess the leak rates and overall complication burden after anterior resection with and without a diverting stoma. METHODS: A 5-year national cohort with prospectively registered data of patients who underwent elective anterior resection for rectal cancer located < 15 cm from the anal verge. Data were retrieved from the Norwegian Registry for Gastrointestinal Surgery and the Norwegian Colorectal Cancer Registry. Primary end point was relaparotomy or relaparoscopy for anastomotic leak within 30 days from index surgery. Secondary endpoints were postoperative complications including reoperation for any cause. RESULTS: Some 1018 patients were included of whom 567 had a diverting stoma and 451 had not. Rate of reoperation for anastomotic leak was 13 out of 567 (2.3%) for patients with diverting stoma and 35 out of 451 (7.8%) (p > 0.001) for patients without. In multivariable analyses not having a diverting stoma (aOR 3.77, c.i 1.97–7.24, p < 0.001) was associated with increased risk for anastomotic leak. However, there were no differences in overall reoperation rates following anterior resection with or without diverting stoma (9.3% vs 10.9%, p = 0.423), and overall complication rates were similar. Reoperation was associated with increased mortality irrespective of the main intraoperative finding. CONCLUSION: Diverting stoma formation after anterior resection is protective against reoperation for anastomotic leak but does not affect overall rates of reoperation or complications within 30 days.