How Pelvic Radiation Impacts Lower Urinary Tract Function in Pediatric Cancer Survivors

Research study background

Survival rates for children with pelvic solid tumors have risen dramatically thanks to advances in multimodal therapy — a combination of chemotherapy, surgery and external beam radiation therapy (EBRT). Yet this success comes with a cost, as each treatment modality contributes to long-term health effects. In one study, 94% of pediatric cancer survivors who received both EBRT and chemotherapy reported late effects.

Chemotherapy agents are known to cause lower urinary tract dysfunction (LUTD) in survivors of various childhood cancers, leading to neurogenic or myotonic bladder changes that can persist long after treatment. EBRT, while effective at destroying tumor cells, unavoidably exposes nearby healthy tissue to radiation, causing temporary inflammation and permanent injury. Together, these therapies may compound the risk of urinary complications over time.

“Our patients who have been treated for childhood cancer have endured so much between therapy, surgery, time in the hospital, missing life events and the fear that comes with these diagnoses,” says Michael Edwards, MD, pediatric oncologist at Children’s Hospital Colorado. “We want to do our best to continue to care for them and their health, even well after the treatment for their cancer ends.”

Despite decades of progress, the long-term effects of pelvic EBRT on bladder and lower urinary tract function remain poorly understood. Few pediatric studies have examined this area of the body, and earlier research relied on outdated radiation techniques or lacked modern urodynamic assessments. As more survivors of pelvic solid tumors reach adulthood, understanding these outcomes has become increasingly important for improving lifelong quality of life and care.

To address this gap, Dr. Edwards and a team of experts in the Center for Cancer and Blood Disorders and the Department of Pediatric Urology at Children’s Colorado conducted a pilot study examining LUT function in children aged 3 and older who were at least one year post-treatment for a solid tumor. Participants were evenly divided into cohorts for a comparison between those who had received pelvic EBRT plus chemotherapy and those who received chemotherapy alone. Among patients who received pelvic EBRT, which was defined as a dose delivered to the bladder, eight had Wilms tumor and eight had pelvic Ewing's sarcoma or rhabdomyosarcoma. Investigators analyzed patient-reported outcomes, non-invasive urodynamic studies (niUDS), as well as results from the Dysfunctional Voiding Symptom Score (DVSS) — a standard questionnaire used to assess urinary symptoms.

They found that 81% of children treated with pelvic radiation exhibited abnormal uroflow patterns, suggesting voiding dysfunction, compared to 56% in the non-radiation cohort. Participants who received both EBRT and chemotherapy were also significantly more likely to exhibit a steady but low urinary flow pattern (44% vs. 6%), suggesting reduced bladder function. The research team’s exploratory analysis also suggested a possible dose–response relationship, with higher radiation doses associated with greater risk. After finding no difference between the groups in DVSS, the team noted that it may not be sufficiently sensitive for this population.

Relevance to practice

“This research underscores that there are late effects of our treatment that go underrecognized and undertreated,” says Dr. Edwards.

The study authors are currently investigating urinary biomarkers to screen for therapy-induced LUTD. They recommend that survivorship clinicians advise patients to promptly report dysuria or gross hematuria rather than waiting for annual screenings. Clinicians should also take detailed urinary histories and refer patients with low thresholds to urology.