Duration of α-1 adrenergic antagonist administration after low-dose-rate brachytherapy for prostate cancer.

Background: Urinary dysfunction is an adverse event of low-dose-rate brachytherapy (LDR-BT) in patients with prostate cancer. We aimed to examine the time to α-1 adrenergic antagonist withdrawal after LDR-BT initiation.

Methods: We retrospectively evaluated 1663 patients who underwent LDR-BT at our hospital during 2004-2022.

Results: Overall, 1485/1663 (89.3%) patients were able to stop using α-1 adrenergic antagonists, 1111 (66.8%) of them within 1 year of LDR-BT. Risk factors for prolonged time to withdrawal were age ≥70 years, taking agents for lower urinary tract symptoms prior to LDR-BT, an International Prostate Symptom Score ≥8, an Overactive Bladder Symptom Score ≥3 and a residual urine volume ≥20 ml. Of the patients who were able to stop taking α-1 adrenergic antagonists, 357/1485 (24.0%) required resumption, 218 (61.1%) of whom did so between 1 and 3 years after LDR-BT. This period matched the period of transient worsening of the urinary symptom score. Finally, multivariable analysis identified supplemental external beam radiotherapy and an Overactive Bladder Symptom Score ≥3 as independent risk factors for α-1 adrenergic antagonist resumption.

Conclusions: Withdrawal of α-1 adrenergic antagonists was possible in 66.8% of patients within 1 year of LDR-BT. Our results suggest that patients who are older or have pre-treatment LUTS may have prolonged deterioration of urinary dysfunction after treatment. Resumption of α-1 adrenergic antagonists 1-3 years after treatment may be associated with urinary symptom flares, and close attention is necessary for patients with supplemental external beam radiotherapy and a high pretreatment Overactive Bladder Symptom Score.