External beam radiotherapy plus high-dose-rate brachytherapy for treatment of locally advanced prostate cancer: the initial experience of the Catalan Institute of Oncology

Abstract

Purpose: The objective of this study was to report initial outcomes in patients with locally advanced prostate cancer (CaP) who underwent external beam radiation therapy (EBRT) treatment combined with high-dose-rate brachytherapy (HDR-BT) as a boost.

Methods and materials: From 2002 to 2007, 114 CaP patients underwent EBRT followed by (192)I HDR-BT. The patients were classified into intermediate- (Group 1) or high- (Group 2) risk groups. The mean total EBRT dose was 60.0Gy (95% confidence interval [CI]: 59.9-60.1) at 2Gy per fraction. After a mean of 20.6 days (95% CI: 18.4-22.8), all the patients received a single-fraction 9-Gy dose of HDR-BT boost. Of the 114 patients in the study, 103 (90.4%) underwent up to 3 years of complete androgen deprivation therapy after diagnosis.

Results: The mean followup for the entire group was 32.1 months (95% CI: 29.9-34.4). The 4-year biochemical failure-free survival rate was 97.4% and treatment was well-tolerated.

Conclusions: Preliminary biochemical control rates after EBRT plus one fraction of 9-Gy HDR-BT are encouraging. This atypical fractionation schedule is cost-effective and reduces patient discomfort and treatment-related risks. More followup is required to confirm these findings.