The Effect of Brachytherapy, External Beam Irradiation and Hormonal Therapy on Prostate Volume

PurposeWe describe the effects of prostate brachytherapy with or without hormonal therapy, or external beam irradiation on gland volume.Materials and MethodsA total of 600 men with localized prostate cancer underwent 125I (357), 103Pd (118) or partial 103Pd combined with external beam irradiation (125) brachytherapy. Of the 600 men 299 (49.8%) received 3 to 9 months of hormonal therapy, which was initiated 3 months before implantation. Hormonal therapy consisted of luteinizing hormone-releasing hormone agonist plus antiandrogen in 251, luteinizing hormone-releasing hormone agonist in 41 and flutamide plus finasteride in 7. Prostate volume measurements were made before the initiation of hormonal therapy, at implantation and yearly. Median followup was 5.2 years. Associations were tested by chi-square analysis. Means were compared by 1-way ANOVA and the Student t test.ResultsMedian initial prostate volume was 38.5 cc (range 9.2 to 151.5). Pre-implantation hormonal therapy resulted in a median prostate volume decrease of 33.1%. The mean reduction for luteinizing hormone-releasing hormone agonist was 27.6%, for luteinizing hormone-releasing hormone agonist plus antiandrogen it was 32.8% and for flutamide plus finasteride it was 10.8% (p = 0.003). Prostate volume decreased 36.6% by year 1, 42.4% by year 4, 45.6% by year 6 and 51.2% by year 8 (p <0.0001). There was no difference in prostate volume reduction at year 1 between men receiving hormonal therapy vs implantation alone. Patients treated with 103Pd had a greater prostate volume reduction at 1 year than those who received 125I (p = 0.004). Conversely patients treated with hormonal therapy and 125I had a smaller prostate volume reduction than those implanted with 125I alone (p = 0.023). After year 1 there were no longer differences between any groups.ConclusionsLuteinizing hormone-releasing hormone agonist plus antiandrogen is more successful for reducing prostate volume before prostate brachytherapy than luteinizing hormone-releasing hormone agonist or flutamide plus finasteride. Hormonal therapy offered no advantage over implantation alone for post-implantation prostate volume reduction. 103Pd appears to reduce prostate volume more rapidly than 125I but this advantage is lost by year 2. No rebound in prostate volume was noted at longer followup.