The effect of neoadjuvant radiotherapy and faecal incontinence, low anterior resection syndrome and anal manometric findings after total mesorectal excision

Abstract

Purpose/Background: Neoadjuvant chemoirradiation is vital in the multi-disciplinary treatment for rectal cancer. However, it may adversely affect the anal sphincter function. The aim of this study was to objectively quantify the effect of neoadjuvant radiotherapy on the postoperative anal function in patients undergoing total mesorectal excision for rectal cancer. Methods/Interventions: Patients who underwent total mesorectal excision for rectal cancers were evaluated with questionnaires on Wexner score, low anterior resection syndrome (LARS) score and anal manometry. They were evaluated at 3 months after surgery or stoma closure, whichever was later. The scores and anal manometric findings were compared between those who had neoadjuvant chemoirradiation and those who had upfront surgery. Results/Outcome(s): A total of 28 patients were evaluated. 57.1% and 42.9% had upfront surgery and neoadjuvant chemoirradiation therapy respectively. The two groups were comparable in terms of age, gender ratio, tumor height and anastomotic height. Patients who had neoadjuvant chemoirradiation had significantly higher median Wexner score, 14.5 vs 6 (p=0.043), significantly greater intra-rectal pressure during push (attempted defecation), 50.25mmHg vs 34.65mmHg (p=0.008), significantly lower rectoanal pressure differential during push, -0.6mmHg vs -23.95mmHg (p=0.031) and significantly lower rectal compliance during balloon inflation 0.03 vs 0.13 (p=0.021). The LARS score, resting sphincter pressure and squeeze sphincter pressure were comparable between the two groups. Conclusions/Discussion: Neoadjuvant chemoirradiation resulted in greater intra-rectal pressure and lower rectoanal pressure differential during attempted defecation. Patients were more likely to have fecal incontinence but the severity of LARS was comparable.