**2. Eligibility criteria, experimental protocol, data presentation and interpretation of the studies selected for presentation in this chapter**

## **2.1 Pathophysiology and natural history of anorectal sequelae following radiation therapy for carcinoma of the prostate**

#### *2.1.1 Subject selection criteria*

The 34 patients, median age = 68 (range 54–79) years, selected for the above study met the following eligibility criteria:


Of the total patient population of 217 patients, 86 patients (57 completed two serial evaluations of anorectal function using an earlier manometric assembly which meant that later serial measurements were no longer comparable, 5 started radiotherapy before baseline evaluation and 24 patients died before 5 years), failed to meet eligibility criterion (ii), 12 patients, who required APC for rectal bleeding after radiotherapy, failed eligibility criterion (iii) and 85 patients, who withdrew consent for anorectal manometry after radiotherapy because of distant domicile from the laboratory, failed eligibility criterion (iv).

#### *2.1.2 Experimental protocol*

Each of the 34 patients meeting all eligibility criteria for the study underwent evaluations of (i) gastrointestinal symptoms (modified LENT-SOMA scales including effect on activities of daily living (ADL), (ii) anorectal motor and sensory function (manometry with a perfused sleeve and multiport assembly incorporating a highly compliant polyethylene bag in the rectum) and (iii) anal sphincteric morphology (endoanal ultrasound) before radiotherapy and at 1 month, then yearly for 5 years after completion of radiotherapy.

#### *2.1.3 Data presentation and interpretation*

Total GI symptom scores increased after radiotherapy and remained above baseline levels at 5 years (**Table 1**). At this time, 48% of patients reported impairment of ADL [2].

The prevalence of persistent urgency of defaecation (44%) was doubled that of rectal bleeding (21%) at 5 years. The % of patients free from the risk of urgency of defecation was significantly less than that of rectal bleeding (**Figure 1**).

All measures of anorectal motor function remained below baseline levels at 5 years (**Table 2**). Furthermore, anal pressures in response to voluntary squeeze and increased intra-abdominal pressure progressively decreased after radiotherapy.

The volume for first perception of rectal distension and that associated with the desire to defaecate both decreased after radiotherapy although only threshold


Abbreviations: *ANOVA, analysis of variance; GI, gastrointestinal; ns, not significant.*

*\* P < .05 Compared with baseline.*

*† P < .01 Compared with baseline.*

*From Yeoh et al. [2], with permission.*

#### **Table 1.**

*Median (range) anorectal symptoms at baseline and 1 month, annually to 5 years after radiation therapy for prostate carcinoma.*

#### **Figure 1.**

*Percent of patients free from urgency of defaecation vs. rectal bleeding 5 years after radiation therapy. GI = gastrointestinal. (From Yeoh et al. [2], with permission).*


#### **Table 2.**

*From*

*Yeoh*

*et*

*al.*

*with*

*Mean ( SE) anal pressurres (sleeve), rectal sensory volumes, rectal compliance, and anal sphincter thickness at baseline and I month, annually to 5 years after radiation therapy for prostate carcinoma.*
