PurposeTo report long-term outcomes for treatment of prostate cancer using dose escalation with high-dose-rate (HDR) brachytherapy and 3-dimensional conformal external beam radiotherapy (3DCRT), and compare them with outcomes for treatment of prostate cancer with 3DCRT alone at the same institution.Methods and Materials
From 1998 to 2003, 587 patients were treated for clinically localized prostate cancer. Patients received either 3DCRT (median, 46 Gy) with a single HDR brachytherapy implant (196 patients) delivering a fractionated dose of 18 Gy (combined group) or 3DCRT (median, 70 Gy; 387 patients; “3DCRT alone”). There were 41.9 % patients with intermediate-risk and 42.6 % with high-risk disease. In all, 441 patients (75.1 % ) received neoadjuvant and 116 patients (19.8 % ) received adjuvant androgen deprivation therapy. The American Society of Therapeutic Radiology and Oncology Phoenix definition for biochemical failure was used.
Results
The median followup was 5.5 years. The 5- and 7-year biochemical control (BC) rates were 82.5 % and 80.3 % , respectively, for the combined group and 81.3 % and 71 % , respectively, for 3DCRT alone; for overall survival, they were 91.9 % and 89.5 % vs. 88.7 % and 86.2 % , respectively, whereas for cause-specific survival, they were 96.9 % and 96.1 % vs. 97.6 % and 96.2 % , respectively. Cox proportional hazard regression analysis for BC revealed that low Gleason grade, HDR brachytherapy combined with 3DCRT, and adjuvant androgen deprivation therapy were significant in predicting BC. Radiation Therapy Oncology Group Grade 3 late urinary and rectal morbidity rates were 7.1 % and 0 % , respectively. No Grade ≥4 reactions were detected.
Conclusions
HDR brachytherapy combined with 3DCRT was associated with improved BC and minimal toxicity in patients with unfavorable prostate cancer compared with conventional 3DCRT.
