In locally advanced prostate cancer, the results of radiotherapy are improved by combination with androgen deprivation therapy. Prostate volume reduction by neoadjuvant hormonal treatment can facilitate dose escalation without increasing the toxicity. The aim of this study is to decide the optimal duration of neoadjuvant androgen deprivation therapy for prostate volume reduction in locally advanced prostate cancer patients scheduled for external beam radiotherapy (EBRT).
Eighteen patients scheduled for external beam radiotherapy with locally advanced prostate cancer (cT2-3N0/xM0) were treated with a nonsteroidal anti-androgen (Bicalutamide) for 9 months in neoadjuvant setting. Repeated CT scan examination was performed 3-monthly to measure prostate volumes until the start of EBRT.
The baseline median prostate volume for enrolled patients was 78cc (95% CI: 58–97cc) with a median volume reduction of 29% (95% CI: 24%–35%) (P <0.0001) after 3 months of bicalutamide. Between 3 and 6 months, a median volume reduction of 11% (95% CI: 6%–15%) (P <0.0001) was observed. No significant volume reduction occurred between 6 and 9 months of hormonal treatment.
In this study, the most significant prostate volume reduction is achieved after 3 months of hormonal treatment with a maximum reduction after 6 months. Therefore, the optimal duration of neoadjuvant androgen deprivation to reduce prostate volume before prostate cancer radiotherapy is 6 months.
Clinical trial identification
All authors have declared no conflicts of interest.