A nomogram for predicting rectovaginal fistula after low anterior resection for rectal cancer

Purpose Rectovaginal fistula (RVF) is a complicated and troublesome complication of low anterior resection (LAR) for rectal cancer. We aimed to investigate the risk factors for post-LAR RVF and develop a predictive nomogram. Methods We performed a retrospective analysis of 821 female patients with rectal cancer who underwent LAR between October 2010 and October 2018. Logistic regression was performed to identify risk factors. A nomogram was developed to predict RVF. Results The incidence of post-LAR RVF was 3.4% (28/821). A multivariate analysis showed that the preoperative serum hemoglobin level (OR 2.449, 95% CI 1.144-5.239), the distance between the tumor and anal verge (OR 4.158, 95% CI 1.392-12.418), surgical procedure (OR 2.369, 95% CI 1.117-5.027), hysterectomy (OR 2.996, 95% CI 1.106-8.833), and bilateral oophorectomy (OR 5.823, 95% CI 1.639-20.689) were significantly associated with the development of RVF. A nomogram was developed, which showed a C-index of 0.824 (95% CI 0.730-0.918) and an adjusted C-index of 0.790. Conclusion This study identified the preoperative serum hemoglobin level, the distance between the tumor and the anal verge, the type of surgical procedure, hysterectomy, and bilateral oophorectomy as predictors of post-LAR RVF. A nomogram was successfully developed. It could aid in the prediction of RVF in patients undergoing LAR.