Sequential assessment of bowel function and anorectal physiology after anterior resection for cancer: a prospective cohort study

Aim: The aim of this study was to investigate changes in bowel function and anorectal physiology (ARP) after anterior resection for colorectal cancer. Method: Patients were recruited from November 2006 to September 2008. Cleveland Clinic Incontinence (CCI) scores and stool frequency were determined by patient questionnaires before surgery (t 0) and at three (t 3), six (t 6), nine (t 9) and 12 (t 12) months after restoration of intestinal continuity. ARP measurements were recorded at T 0, T 3 and T 12. Endoanal ultrasound was performed at T 0 and T 12. Results: Eighty-nine patients were included. CCI score increased postoperatively then normalized, whereas stool frequency did not change. Patients who had neoadjuvant radiotherapy or a lower anastomosis had increased incontinence and stool frequency in the postoperative period, whereas those with defunctioning stomas or open surgery had increased stool frequency alone. Maximum resting pressure, volume at first urge and maximum rectal tolerance were reduced throughout the postoperative period. Radiotherapy, lower anastomosis and defunctioning stoma (but not operative approach) altered manometric parameters postoperatively. Maximum rectal tolerance correlated with incontinence and first urge with stool frequency. The length of the anterior internal anal sphincter decreased postoperatively. Conclusions: Incontinence recovers in the first year after anterior resection. Radiotherapy, lower anastomosis, defunctioning stoma and open surgery have a negative influence on bowel function. ARP may be useful if bowel dysfunction persists beyond 12 months.