Diabetes Is an Independent Risk Factor for Radiation-Induced Hematuria After Robotic Stereotactic Body Radiotherapy for Prostate Cancer.

OBJECTIVES

To evaluate the incidence, timing, and clinical predictors of radiation-induced hematuria following robotic stereotactic body radiation therapy (SBRT) for localized prostate cancer.

METHODS

This retrospective single-center cohort study included 397 patients treated with robotic SBRT between 2013 and 2019 for localized prostate cancer. All patients received 36.25 Gy in 5 fractions with the urethral sparing technique. Radiation-induced hematuria was defined as gross hematuria or clinically significant microscopic hematuria without alternative etiology. Incidence, time to first event, and related interventions were assessed. Severity was graded using CTCAE version 5.0. Candidate predictors were selected based on the literature. Cox proportional hazards modeling identified clinical predictors of radiation-induced hematuria.

RESULTS

At a median follow-up of 56 months (IQR 29-79), 48 patients (12.1%) developed radiation-induced hematuria, occurring at a median of 30 months (IQR 19-49) after radiation treatment. Severe events (grade 3) were rare, affecting only 5 patients (1.3%). Diagnostic cystoscopy was performed in 35 patients (72.9%) and 6 patients (12.5%) required a total of 10 therapeutic interventions. Diabetes was the only independent predictor (HR 2.63, 95% CI 1.37-5.00, p = 0.004), while age, anticoagulant use, prostate volume, and Charlson Comorbidity Index showed no significant association.

CONCLUSION

Radiation-induced hematuria following robotic SBRT is predominantly low-grade and late-occurring, confirming the favorable genitourinary toxicity profile. These findings help clinicians better understand this SBRT-related toxicity and provide more accurate patient counseling regarding timing and severity of potential hematuria. Diabetes was identified as an independent risk factor and may have clinical implications; however, whether optimization of glycemic control reduces hematuria risk remains uncertain and requires further investigation.