Anal function after endoluminal locoregional resection by transanal endoscopic microsurgery and radiotherapy for rectal cancer.

Aim: In patients with rectal cancer, surgery and chemoradiotherapy may affect anal sphincter function. Few studies have evaluated anorectal function after neoadjuvant chemoradiotherapy (n-CRT) and/or transanal endoscopic microsurgery (TEM). The aim of this study was to evaluate the effects of n-CRT and TEM on anorectal function.

Method: Thirty-seven patients with rectal cancer underwent anorectal manometry and Wexner scoring for faecal incontinence at baseline, after n-CRT (cT2-T3N0 cancer) and at 4 and 12 months after surgery. Water-perfused manometry measured anal tone at rest and during squeezing, rectal sensitivity and compliance. Twenty-seven and 10 patients, respectively, underwent TEM without (Group A) or with n-CRT (Group B).

Results: In Group A, anal resting pressure decreased from 68 ± 23 to 54 ± 26 mmHg at 4 months (P = 0.04) and improved 12 months after surgery (60 ± 30 mmHg). The Wexner score showed a significant increase in gas incontinence (59%), soiling (44%) and urgency (37%) rates at 4 months, followed by clinical improvement at 1 year (41%, 26% and 18%, respectively). In group B, anal resting pressure decreased from 65 ± 23 to 50 ± 18 mmHg at 4 months but remained stable at 12 months (44 ± 11 mmHg, P = 0.02 vs preoperative values - no significant difference compared with evaluation at 4 months). Gas incontinence, soiling and urgency were observed in 50%, 50%, 25% and in 38%, 12% and 12% of cases, respectively, 4 and 12 months after treatment.

Conclusion: TEM does not significantly affect anal function. Instead, n-CRT does affect anal function but without causing major anal incontinence.