Prostate volume, baseline urinary function, and their association with treatment choice and post-treatment urinary function in men treated for localized prostate cancer

Background: Benign prostatic hyperplasia, lower urinary tract symptoms, and prostate cancer often co-occur. Their effect on urinary function is an important consideration regarding prostate cancer treatment choices. While prostate volume (PV) and urinary symptoms are commonly used in treatment choice decision making, their association with post-treatment urinary function is unknown. We evaluated the associations between PV and baseline urinary function with treatment choice and post-treatment urinary function among men with localized prostate cancer. Methods: We identified 1647 patients from CEASAR, a multicenter population-based, prospective cohort study of men with localized prostate cancer, for analysis. Primary outcomes were treatment choice and health-related quality of life (HRQOL) assessed by the 26-item Expanded Prostate Index Composite (EPIC-26) at pre-specified intervals up to 5 years. Multivariable analysis was performed, controlling for demographic and clinicopathologic features. Results: Median baseline PV was 36 mL (IQR 27–48), and baseline urinary irritative/obstructive domain score was 87 (IQR 75–100). There was no observed clinically meaningful association between PV and treatment choice or post-treatment urinary function. Among patients with poor baseline urinary function, treatment with radiation or surgery was associated with statistically and clinically significant improvement in urinary function at 6 months which was durable through 5 years (improvement from baseline at 5 years: radiation 20.4 points, surgery 24.5 points). Conclusions: PV was not found to be associated with treatment modality or post-treatment urinary irritative/obstructive function among men treated for localized prostate cancer. Men with poor baseline urinary irritative/obstructive function improve after treatment with surgery or radiation therapy.