The effectiveness and side effects of conformal external beam radiotherapy combined with high-dose-rate brachytherapy boost compared to conformal external beam radiotherapy alone in patients with prostate cancer

BACKGROUND: Clinical data that compare external-beam radiotherapy (EBRT) combined with high-dose-rate brachytherapy (HDR-BT) boost versus EBRT alone are scarce. The analysis of published studies suggest that biochemical relapse-free survival in combined EBRT and HDR-BT may be superior compared to EBRT alone. We retrospectively examined the effectiveness and tolerance of both schemes in a single center study. METHODS: Between March 2003 and December 2004, 229 patients were treated for localized T1-T2N0M0 prostate cancer. Median age was 66 years (range, 49 – 83 years). PSA level ranged from 0.34 to 64 ng/ml (median 12.3 ng/ml) and Gleason score ranged from 2 to 10. The analysis included 99 patients who underwent EBRT with HDR-BT (group A) and 130 patients who were treated with EBRT alone (group B). RESULTS: Median follow-up was 6 years. Biochemical relapses occurred in 34% vs. 22% (p = 0.002), local recurrences in 17% vs. 5% (p = 0.002), and distant metastases in 11% vs. 6% (p = 0.179) of patients in groups A and B, respectively. Five-year biochemical relapse-free survival was 67% vs. 81% (p = 0.005), local recurrence-free survival 95% vs. 99% (p = 0.002), metastases-free survival 95% vs. 94% (p = 0.302) for groups A and B, respectively. Five-year overall survival was 85% in both groups (p = 0.596). Grade 2/3 late GI complications appeared in 9.2% and 24.8% (p = 0.003), respectively. Grade 2/3 late GU symptoms occurred in 12% in both groups. CONCLUSIONS: Although because of the retrospective character of the study and nonrandomized selection of fractionation schedule the present conclusions had limitations EBRT alone appeared more effective than EBRT combined with HDR-BT. It was likely the result of the less frequent use of androgen deprivation therapy (ADT) for combined scheme group, too low dose in a single BT fraction or inadequate assumptions regarding fractionation sensitivity of prostate cancer.