Anorectal function after modern conformal radiation therapy for prostate cancer: a pilot study

We evaluated whether, and if so to what extent, radiotherapy applied on a series of patients with prostate cancer influenced the patient's bowel habits and anorectal function. Ten consecutive patients participated in the study. The median age of the patients was 74 years (range, 61-71) and the average follow-up period was 22 (range, 15-28) months. Four patients were irradiated using external beam radiotherapy (2 Gy/day for a total of 70 Gy); 6 patients were irradiated with a combination of external beam radiotherapy (50 Gy, 2 Gy/day) and high dose rate brachytherapy (two 10-Gy fractions). Upon interview, patients disclosed characteristic functional disturbances such as urgency with occasional accidents, faecal soiling and spotting of underwear. Involuntary release of gas was another embarrassing problem. One or more of these problems were present in half of the patients. Endoscopy disclosed signs of mild proctitis. Sphincter pressure, rectal capacity and the volume threshold for appreciation of defecation urge were all significantly lower in patients than in 10 age-matched controls. In conclusion, disturbances of anorectal function with imperfection of incontinence still occur so some extent despite improved precision, and reduced margins offered by the modern conformal radiation therapy of prostate cancer. Anal sphincter function, the reservoir capacity of the rectum and its sensory function are adversely affected and radiation proctitis with rectal fibrosis and damage of the extrinsic innervations of the anal sphincters appear to be the principal causative factors. Although conformal radiotherapy together with better positioning may be two substantial improvements of modern radiotherapy, further improvements are needed.