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

ABSTRACT

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.