Risk factors for developing anorectal dysfunction after anterior resection.

BACKGROUND Anterior resection (AR) may result in defecatory dysfunction and the cause is multifactorial. The aim was to explore if dysfunction could be related to the part of the colon used for anastomosis (sigmoid or descending) and to identify other possible risk factors for bowel dysfunction after AR. METHODS This is a retrospective study based on prospectively registered data from a regional registry at the surgical department in Vastmanland 1996-2019. Bowel function was registered at 1 year after AR or after stoma reversal. In total, 470 stage I-III rectal cancer patients had AR whereof 412 were included in this study. RESULTS Clustering was seen in 57%, incontinence 29%, urgency 22%, and evacuatory dysfunction 16%. The part of the colon used for anastomosis, level of vascular tie, and gender were not significantly associated with defecatory dysfunction. The higher the anastomotic level, the lower the risk of incontinence (OR 0.75; CI 0.63-0.90; p < 0.001) and clustering (OR 0.78; CI 0.67-0.90; p < 0.001). Compared with patients without a loop-ileostomy, an increased risk of clustering (OR 1.89; 1.08-3.31; p = 0.03), incontinence (OR 2.48; 1.29-4.77; p < 0.01), and urgency (OR 4.61; CI 2.02-10.60; p < 0.001) was seen after loop-ileostomy closure. Preoperative radiotherapy had a negative impact on continence and clustering seen mainly in the unadjusted analysis. CONCLUSION The part of the colon used for anastomosis was not a significantly associated functional outcome after anterior resection. Low anastomotic level and having had a diverting ileostomy were independent risk factors associated with negative functional outcomes.