Decline in acute urinary toxicities with increased institutional experience: 15-year experience of permanent seed prostate brachytherapy in a single Australasian institution.

PURPOSE: To evaluate the incidence of acute urinary toxicity after permanent seed prostate brachytherapy (BT) over a 15-year period.

METHODS AND MATERIALS: The study consisted of 782 prostate cancer patients treated with BT. All patients completed self-administered International Prostate Symptoms Score (IPSS) at baseline and during regular follow-up. We evaluated the risk of acute urinary retention (AUR) up to 3 months post-BT and lower urinary tract symptom (LUTS) resolution (defined as return to within two points of baseline IPSS score) at regular intervals, up to 24 months post-BT. Univariate and multivariate logistic regressions were used to evaluate the effect of various patient, tumor, and treatment factors on the risk of AUR and the likelihood of LUTS resolution.

RESULTS: Ninety-six patients (12%) developed AUR at a median of 1 day post-BT. Increased peak urinary flow is independently associated with lower risk of AUR (odds ratio [OR] = 0.94; 95% confidence interval [CI] = 0.91-0.97). Decline in incidence of AUR was observed over time with increased institutional experience (p = 0.03). Of the 646 patients with a minimum of 24-month follow-up, 29%, 49%, and 72% had LUTS resolution at 6, 12, and 24 months, respectively. Patients who had pre-BT transurethral resection of prostate (OR = 2.4; 95% CI = 1.5-4.0), cytoreductive neo-adjuvant androgen deprivation (OR = 2.0; 95% CI = 1.0-4.0), and higher baseline IPSS (OR = 1.1; 95% CI = 1.07-1.19) are more likely to report LUTS resolution at 24 months.

CONCLUSIONS: We reported decline in AUR over time with increased institutional experience in one of the largest Australasian BT series. Approximately three-quarters of patients achieved LUTS resolution at 24-month follow-up.