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.