Predicting Urinary Function Outcomes Following Low-dose-rate Brachytherapy for Prostate Cancer

Abstract

Background and objective: Our aim was to develop a tool using readily available clinical parameters to predict the probability of poor urinary function following low-dose-rate brachytherapy (LDR-BT) for localized prostate cancer. Methods: Data from the multicentre, prospective Swiss LDR-BT cohort were analyzed for men treated with LDR-BT. Inclusion criteria were minimum follow-up of 3 yr or postoperative treatment with transurethral resection of the prostate (TURP). A total of 914 men were analyzed, with complete data available for 607 men. Pre-interventional variables assessed were International Prostate Symptom Score (IPSS), prostate volume (PV), maximum urinary flow rate, prostate-specific antigen, postvoid residual urine volume, and age. The primary outcome was poor urinary function after LDR-BT, defined as an IPSS-Quality of Life score >3 (“mostly dissatisfied” or worse) at 3 yr or the occurrence of TURP during follow-up. Associations were evaluated using univariable and multivariable logistic regression. Receiver operating characteristic curve analysis was also performed. Key findings and limitations: Poor urinary function outcomes were observed in 46 patients (5.0%). Significant predictors included pre-interventional IPSS (adjusted odds ratio [aOR] per point 1.18; p < 0.001) and PV (aOR per ml, 1.04; p = 0.004). Limitations of the study include potential selection bias and the absence of external validation. Conclusions and clinical implications: Pre-interventional IPSS and PV were significant predictors of poor urinary function after LDR-BT for prostate cancer. A risk calculator based on these parameters was developed to assist individualized treatment planning. Further studies are needed to validate these findings before they can be applied in routine clinical practice. Patient summary: We created a tool to predict the likelihood of urinary problems after a type of radiotherapy called brachytherapy for prostate cancer. The size of the prostate and urinary symptoms before treatment were associated with poor urinary function after treatment. This tool could help doctors and patients in making informed decisions about treatment for prostate cancer.

Keywords

• Prostate cancer
• Low-dose-rate brachytherapy
• Urinary function
• Outcome prediction
• Lower urinary tract symptoms