Manometric evaluation of anorectal function in patients treated with neoadjuvant chemoradiotherapy and total mesorectal excision for rectal cancer

Background An altered anorectal function is reported after chemoradiotherapy (CRT) and surgery for rectal cancer. Aim The aim of this study was to clarify the relative contribution of neoadjuvant chemoradiation and surgical resection on the impairment of anorectal function as evaluated by anorectal manometry. Methods Thirty-nine patients with rectal cancer, who underwent neoadjuvant CRT and laparoscopic rectal resection, were evaluated with the Pescatori Faecal Incontinence score, and with anorectal manometry: before neoadjuvant therapy (T0), after neoadjuvant therapy and before surgery (T1), 12 months after stoma closure (T2). Results Resting and/or maximum squeeze pressure and/or volume thresholds for urgency were below the normal values in 12 (30%) patients at baseline. After CRT the mean resting pressure significantly decreased (p = 0.007). Surgery determined a significantly decrease of the resting pressure (p = 0.001), of the maximum squeeze pressure (p = 0.001) and of the volume threshold for urgency (p = 0.001). Impairment of continence was reported by 5, 11 and 18 patients at T0, T1 and T2, with a mean incontinence score of 3, 3.8 and 3.9 respectively. Conclusions CRT is detrimental to the function of the internal anal sphincter. Rectal resection significantly affects both internal and external anal sphincter function and the maximum tolerated volume of the neo-rectum, particularly in patients with low rectal cancer, significantly impairing anal continence.