Urinary incontinence after high-dose-rate brachytherapy boost treatment for prostate cancer

To evaluate urinary incontinence (UI) and to elucidate potential risk factors important for the appearance or deterioration of pre-existing UI after high-dose-rate boost treatment of prostate cancer.

The change in grade of UI regarding the state at the start of treatment was assessed in 88 patients, consecutively treated from October 2006 through April 2011 with high-dose-rate brachytherapy of 3 × 6-7 Gy to 50-50.4 Gy of external-beam radiation. Increase in UI grade was defined as deterioration of UI (DUI). The impact of patients and treatment characteristics on third year prevalence of DUI was analyzed by using binary logistic regression method.

At third year, DUI of followup was evidenced in 17/81 (20.9%) patients. It significantly impacted micturition quality (p = 0.015) and was associated with [Formula: see text] (odds ratio [OR]: 1.14; 95% confidence interval [CI]: 1.03-1.26; p = 0.010), diabetes (OR: 6.73; 95% CI: 1.17-38.56; p = 0.032), and initial nocturnal micturition frequency (OR: 3.72; 95% CI: 1.03-13.04; p = 0.045). Based on a multivariate model, a range of "safe" [Formula: see text] doses is suggested (no risk factor: 21.9 Gy, frequent initial nocturnal micturition only: 12.0 Gy, diabetes only: 7.6 Gy, both risk factors: no safe dose).

The study featured on urinary bladder base as a risk structure for UI. By taking account of the dose to urinary bladder base in conjunction with diabetes and initial nocturnal micturition frequency, the risk of UI could be reduced.