Effect of Pelvic External Beam Radiation Therapy on Lower Urinary Tract Function of Pediatric Patients.

Background: Pediatric patients with pelvic solid tumors often receive multimodal treatment, but the long-term effects of this treatment on lower urinary tract (LUT) function are not well-described. This prospective cohort study (NCT05818462) investigates the effect of external beam radiation therapy (EBRT) on LUT function by comparing patient-reported outcome measures, non-invasive urodynamic studies, and post-void residuals (PVRs) amongst childhood cancer survivors (CCS).

Methods: All subjects were CCS greater than 1 year off-therapy for a pediatric solid tumor. Subjects were divided into cohorts by whether they had received pelvic EBRT. Research subjects completed the Dysfunctional Voiding Scoring system (DVSS) survey, uroflow testing, and PVR bladder scan.

Results: Thirty-two patients enrolled; half received pelvic EBRT (mean 30.0 Gy). There was an equal number of patients exposed to alkylators (69%) in each cohort. Radiation cohort was further off therapy (5.3 vs. 4.0 years). The pelvic radiation cohort was more likely to have abnormal uroflow patterns (81% vs. 56%, p = 0.12). The flow pattern distribution differed between groups (p = 0.03); the pelvic radiation cohort was more likely to have a "plateau"-shaped curve (44% vs. 6%) and abnormal PVR (odds ratio [OR] 9.0, p = 0.002). Exploratory conditional likelihood ratio models yielded potential associations between pelvic EBRT and LUTD, as well as a potential dose-response. There was no difference in DVSS scores between cohorts.

Conclusion: EBRT appears to affect LUT function in CCS who received pelvic EBRT. DVSS does not appear useful as a screening tool in this population. Further study is needed to better appreciate the impact of EBRT on LUT function and develop more accurate screening tools.