Focal brachytherapy for localized prostate cancer: Urinary toxicity depends on tumor location.

PURPOSE: To evaluate whether patients with prostate cancer have worse functional urinary recovery with focal brachytherapy (FBT) at the base versus the apex of the prostate.

METHODS AND MATERIALS: The functional outcomes of patients treated with FBT at the base of the prostate were compared with those of patients treated with FBT at the apex. Urinary symptoms, continence, and erectile dysfunction were measured using the International Prostate Symptom Score (IPSS), International Continence Score (ICS), and International Index of Erectile Function (IIEF-5) questionnaires, respectively, at baseline and at 6, 12, and 24 months after treatment.

RESULTS: Twenty-eight and 13 patients were treated with FBT at the apex and the base, respectively, of the prostate. A significant difference between groups was found in the IPSS score at 6 months (mean IPSS: apex 6.4 ± 4.7, base 10.6 ± 5.7; p = 0.02), but not at baseline or at 12 and 24 months after treatment. On multivariate analysis, only FBT at the base of the prostate remained an independent predictor of worsening urinary symptoms (odds ratio, 5.8; p = 0.04).

CONCLUSIONS: At 6 months after FBT, significantly less urinary toxicity was found in patients who underwent FBT at the apex versus the base of the prostate. Continence and sexual side effects were minimal in all patients.