Prostate volume reduction with androgen deprivation therapy before interstitial brachytherapy.

Purpose: We assessed the degree of prostate downsizing using androgen deprivation, and determined its relation to clinical and pathological variables.

Materials And Methods: From June 1994 to January 2000, 107 patients with prostate cancer received androgen deprivation before interstitial brachytherapy at our hospital. All charts were reviewed for clinical, pathological and treatment related variables. Prostate volume was measured using transrectal ultrasound. All variables were analyzed with regard to the degree of prostate downsizing.

Results: Mean percent volume reduction of the prostate was 33% after a 3.7-month average duration of androgen deprivation. Larger prostate volume before androgen deprivation and longer deprivation duration statistically correlated with mean percent volume reduction. Simple linear and multiple regression analyses revealed that these 2 variables remained significant predictors of percent volume reduction. Subgroup analysis indicated that a significant difference was seen in patients who received androgen deprivation with luteinizing hormone releasing hormone agonists alone versus those who received treatment with total androgen blockade (luteinizing hormone releasing hormone agonists plus antiandrogens 30% versus 35%, p = 0.04), and when prostate volume before androgen deprivation was less than 50 cc versus larger volumes (30% versus 35%, p = 0.01). Of patients with an initial prostate volume of greater than 50 cc 82% achieved a volume of less than 50 cc after androgen deprivation therapy.

Conclusions: Androgen deprivation therapy before brachytherapy is a method of downsizing the prostate to overcome anatomical limitations, including larger gland volume and pubic arch interference.