*Pathophysiology, Natural History and Approaches to Treatment and Prevention of Radiation… DOI: http://dx.doi.org/10.5772/intechopen.99269*

volumes for sensory perception at 5 years remained below those recorded at baseline (**Table 2**). Rectal compliance progressively reduced with time after radiotherapy and remained persistently lower at 5 years compared with that recorded at baseline **Table 2**).

Radiotherapy had no effect on the thicknesses of the IAS and EAS (**Table 2**).

There were no differences in any of the GI symptoms nor in any anorectal functional and anal sphincteric morphological measurements between patients randomized to the 2 radiation dose schedules.

5 years after radiotherapy for carcinoma of the prostate, persistent GI symptoms continue to have a significant impact on ADL of almost 50% of all patients. At this time, the prevalence of urgency of defecation (44%) was doubled that of rectal bleeding (21%). Increased GI symptoms after radiotherapy were associated with progressive or persistent reductions of basal anal pressures and pressures in response to voluntary squeeze and increased intra-abdominal pressures, rectal compliance and volumes of sensory perception and desire to defaecate. These physiological changes, which suggest weakness of the IAS and EAS as well as stiffness of the rectal wall and consequent increased rectal sensitivity, are the pathogenetic basis for anorectal dysfunction after radiotherapy for carcinoma of the prostate. The etiology of the motility changes is likely to be neurogenic in the intrinsic neural network in the bowel wall and/or extrinsic nerve supply such as the pudendal nerves since muscle tissue, particularly striated muscle is more resistant to radiation damage.

#### **2.2 A retrospective study of the effects of pelvic irradiation for gynecological cancer on anorectal function**

#### *2.2.1 Subject selection criteria*

The 15 patients, median age = 67 (range 47–84) years, selected for the study met the following eligibility criteria:


Of the original total patient population of 33 patients, 6 had died and 2 had been lost to follow-up since completing the previous study [20]. The 25 remaining patients were invited to participate in this study, 10 refused including two patients who had intermittent episodes of rectal bleeding.

9 healthy females, median age = 63 (range 41–70) years served as control subjects.

#### *2.2.2 Experimental protocol*

The following parameters were assessed in each subject: (i) anorectal symptoms (questionnaire), (ii) anorectal motor and sensory function (manometry with a perfused sleeve and multiport assembly incorporating a highly compliant latex

balloon in the rectum and concurrent electromyography of the anal sphincters) and (iii) anal sphincteric morphology (endoanal ultrasound).
