Hypothesis / aims of study
The impact of radiation therapy (XRT) on urodynamic (UDS) parameters and outcomes of artificial urinary sphincter (AUS) implantation in post-radical prostatectomy (RP) patients remains controversial. Some studies have reported no adverse radiation effects, while others noted changes in preoperative UDS and continence outcomes. We reviewed our AUS implants to compare the UDS parameters and continence outcomes between post-RP patients with and without a history of XRT.
Study design, materials and methods
We reviewed the charts of patients undergoing AUS implant for post-RP incontinence and divided patients into two groups: those with (Group 1) and those without (Group 2) a history of pelvic XRT. The groups were compared with respect to demographic (age, comorbidities, prior urethral procedures), clinical (symptom scores, voiding diaries, pad usage), and UDS (cystometrogram with leak point testing and pressure-flow studies) variables as well as postoperative outcomes.
Results
Of 96 patients reviewed, 50 (52%) had a history of XRT. The mean age at the time of AUS placement was 67.8 years (SD 7.82). Mean follow-up for Group 1 and Group 2 patients was 2.8 years (SD 4.0) and 3.1 years (SD 3.2), respectively. There were no significant differences between groups with respect to demographics, prior urethral procedures, preoperative AUA symptom scores, voiding frequency, and pads per day (ppd) usage (6.0 in Group 1, 5.4 in Group 2). However, maximum voided volume per void was significantly lower in Group 1 (mean 282 mL vs 479 mL, p=0.008). UDS characteristics were not significantly different between groups. Following AUS implant, there was no significant difference in pad usage between groups (1.6 ppd in Group 1, 1.3 ppd in Group 2, p=0.64) with social continence (0-1 ppd) achieved in 69% of Group 1 and 70% of Group 2 patients. There was also no signficant difference seen in 24-hr pad weights: 14.37 g in Group 1 versus 31.36 g in Group 2 (p=0.194). Seven patients in Group 1 experienced device erosion (14%) compared to 3 patients in Group 2 (6.5%).
Interpretation of results
In a cohort of post-RP patients who underwent AUS implant, we did not find any major differences between patients with and without pelvic XRT with regard to demographic, clinical, and UDS parameters, apart from a smaller voided volume per void in the XRT group. In addition, AUS outcomes were similar between groups. As a result, the necessity of UDS prior to AUS implantation in post-RP patients is questionable. These results suggest that UDS may offer limited prognostic value, warranting further studies on its clinical utility in this population.