Late intestinal adverse effects following radiotherapy

This review analyzed recent publications investigating the late intestinal adverse effects following radiotherapy treatments.

Radiotherapy is frequently used in the treatment of prostate cancer. Although radiation techniques have improved over recent years, radiotherapy still commonly causes intestinal adverse events. Despite this fact, high quality evidence as to the incidence and management of radiotherapy induced intestinal damage is scarce. This analysis reviewed all recently published data investigating the late complications of radiotherapy (those appearing more than 3 months following treatment) affecting intestinal function.

21 studies, including a total of more than 1000 patients, were included in this analysis.  9 of the studies examined anal function following radiotherapy. 6 of these studies demonstrated that resting anal pressure (a measurement of sphincter function and continence) was significantly reduced following radiotherapy. 9 of the studies examined rectal function following radiotherapy. The ability of the rectal wall to properly distend was significantly impaired after radiotherapy in 7 of the 9 studies. In most studies, these disturbances to rectal and anal function were shown to be associated with increased urgency and frequency of bowel movements or incontinence. Studies assessing changes of the rectal lining (also called the rectal mucosa) revealed widening of small blood vessels (referred to as telangiectasia) in 73% of patients following radiotherapy. Telangiectasias, particularly when numerous, were associated with rectal bleeding. Swelling and congestion of the mucosa was seen in 33% of patients following radiotherapy. However, radiotherapy was not found to be associated with necrosis (tissue death) of the rectal mucosa, and 3 studies reported improvements in rectal mucosa during longer follow-ups.

This analysis found no published evidence regarding the long term effects of radiotherapy on intestinal function 3 or more years following treatment. Little data was found concerning the possible methods of reducing the incidence of late adverse intestinal effects, such as endorectal balloons (an inflatable balloon used to immobilize the prostate and rectum during radiotherapy). In addition, no consensus was found regarding the optimal treatment of rectal bleeding following radiotherapy.

This review concluded that radiotherapy reduces anal resting pressure, decreases rectal distendability, and induces telangiectasias of the rectal mucosa. These changes are frequently associated with incontinence, urgency and frequency of bowel movements and rectal bleeding. Furthermore, this review indicated a staggering lack of high quality evidence regarding the management and prevention of radiotherapy induced intestinal adverse effects.