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.