Objectives

Lower urinary tract symptoms are transiently exacerbated by low-dose-rate brachytherapy (LDR-BT) for prostate cancer and recover to pretreatment levels 1 year thereafter. Generally, these symptoms are influenced by temperature. We aimed to search for factors affecting the lower urinary tract symptoms after seed implant including seasons.

Methods

We retrospectively enrolled 812 patients who underwent LDR-BT at Nara Medical University Hospital from January 2010 to December 2018 and for whom the International Prostate Symptom Score, Overactive Bladder Symptom Score, and frequency volume charts were available. We investigated the relationships between lower urinary tract symptoms, 24-hours urinary frequency, 24-hours urinary volume before and after seed implant, radiation dose, and season of seed implant.

Results

The mean age was 69.5 years. The mean prostate volume was 24.2 mL. The International Prostate Symptom Score, Overactive Bladder Symptom Score, and 24-hours urinary frequency increased until 3 months and gradually decreased over 6 months after seed implant. Multiple linear regression analysis revealed that 24-hours urinary frequency at 3 months after seed implant was significantly influenced by external beam radiotherapy, larger prostate volume before implant, higher 24-hours urinary frequency at baseline, larger 24-hours urinary volume at 3 months after implant, and performance of implant in summer.

Conclusions

Lower urinary tract symptoms worsened 3 months after seed implant of LDR-BT regardless of the season of implant. The urinary frequency 3 months after seed implant was slightly lower when seed implant was performed in the summer.