Improved survival for patients with prostate cancer receiving high-dose-rate brachytherapy boost to EBRT compared with EBRT alone

Purpose: High-dose-rate (HDR)brachytherapy boost is a treatment of intermediate- to high-risk prostate cancer, but long-term clinical outcome data are sparse. We report long-term survival and toxicity data in a cohort of patients treated in a single institution. Methods: Between 1998 and 2004, 654 patients with localized prostate cancer received either 3-dimensional conformal radiotherapy (median 46 Gy)with an HDR (median 18 Gy in three fractions)boost (“3-D conformal radiotherapy [3DCRT]+ HDR”; 215 patients)or 3DCRT alone (“3DCRT”; median 70 Gy; 439 patients)with curative intent. Men with National Comprehensive Cancer Network intermediate risk were offered neoadjuvant androgen deprivation and with high risk were also offered adjuvant androgen deprivation. Data collection included patient-reported outcome measures. Results: The 3DCRT + HDR group was older (72.3 vs. 68.9 yrs), had higher presenting PSAs (iPSA)(15.66 and 12.57 ng/mL, respectively), higher proportion of Gleason scores >7 (15.3% vs. 12.4%), and higher proportions of extracapsular disease (29.3% vs. 25.5%). 3DCRT + HDR men had lower proportions of low-risk patients (3.3% vs. 19.4%)and higher proportions of high-risk patients (50.7% vs. 37.4%)than the 3DCRT group. The 5-, 10-, and 15-year overall survival was superior at 92%, 81%, and 67%, respectively, for the 3DCRT + HDR group, compared with 88%, 71%, and 53%, respectively, in the 3DCRT group (p < 0.001). The 5-, 10-, and 15-year cause specific survival also favored the HDR boost group with survival of 96%, 93%, and 87% (3DCRT + HDR)and 95% 88% and 79% (3DCRT), respectively (p < 0.037). Conclusions: HDR brachytherapy boost in conjunction with 3DCRT offered superior overall survival and cause-specific survival in our patient population.