Anal sphincter dysfunction in patients treated with primary radiotherapy for anal cancer: a study with the functional lumen imaging probe

Abstract

Background: Sphincter-sparing radiotherapy or chemoradiation are standard treatments for patients with anal cancer. The ultimate treatment goal is full recovery from anal cancer with preserved anorectal function. Unfortunately, long-term survivors often suffer from severe anorectal symptoms. The aim of the present study was to characterize changes in anorectal physiology after radiotherapy for anal cancer. Method: We included 13 patients (10 women, age 63.4 ± 1.9) treated with radiotherapy or chemoradiation for anal cancer and 14 healthy volunteers (9 women, age 61.4 ± 1.5). Symptoms were assessed with scores for fecal incontinence and low anterior resection syndrome. Anorectal physiology was examined with anorectal manometry and the Functional Lumen Imaging Probe. Results: Patients had a median Wexner fecal incontinence score of 5 (0–13) and a median LARS score of 29 (0–39). Compared to healthy volunteers, patients had lower mean (±SE) anal -resting (38 ± 5 vs. 71 ± 6, p .4), urge (103 (54-176) vs. 90 (32-212), p >.6) or maximum tolerable volume (173 (86–413) vs. 119.5 (54–269) ml, p >.10). Conclusion: Patients treated with radiotherapy or chemoradiation for anal cancer have low anal resting and squeeze pressures as well as reduced resistance to distension and flow.