To compare rectal toxicity, urinary toxicity, and nadir+2 PSA relapse-free survival (bRFS) in two consecutive Phase II protocols of high-dose-rate (HDR) brachytherapy used at the authors institution from 2001 to 2012.
Patients with National Comprehensive Cancer Network high risk and very high risk prostate cancer enrolled in studies HDR4 (2001-2007, n = 183) and HDR2 (2007-2012, n = 56) were analyzed. Patients received minipelvis external beam radiation therapy/intensity-modulated external radiotherapy to 54 Gy and 2 years of androgen blockade along with HDR brachytherapy. HDR4 protocol consisted of four 4. 75 Gy fractions delivered in 48 hours; the HDR2 protocol delivered two 9. 5 Gy fractions in 24 hours. Average 2-Gy equivalent dose (α/β = 1. 2) prostate D90 doses for the HDR4 and HDR2 groups were 89. 8 Gy and 110. 5 Gy, respectively (p = 0. 0001). Both groups were well balanced regarding risk factors. Prior transurethral resection of the prostate was more frequent in the HDR2 group (p = 0. 001).
After a median followup of 7. 4 years (range, 2-11. 2), there was no difference in adverse grade ≥ 2 rectal events (HDR4 = 10. 4% vs. HDR2 = 12. 5%; p = ns) or grade ≥3 (HDR4 = 2. 2% vs. HDR2 = 3. 6%; p = ns). No differences in urinary grade ≥2 adverse events (HDR4 = 23% vs. HDR2 = 26. 8%; p = ns) or grade ≥3 (HDR4 = 7. 7% vs. HDR2 = 8. 9%; p = ns) were detected. The 7-year bRFS for HDR4 and HDR2 protocols was 88. 7% and 87. 8%, respectively (p = ns).
HDR4 and HDR2 protocols produce similar results in terms of toxicity and bRFS at the intermediate time point of 7 years.
Brachytherapy. 2016 Jan 29 [Epub ahead of print]
Alicia Olarte, Mauricio Cambeiro, Marta Moreno-Jiménez, Leire Arbea, José Luis Pérez-Gracia, Ignacio Gil-Bazo, Ignacio Pascual, Javier Aristu, Rafael Martínez-Monge
Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain; Instituto de Investigación Biosanitaria de Navarra (IdiSNA), Pamplona, Navarre, Spain. , Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Medical Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Medical Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Urology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain. , Department of Radiation Oncology, Clínica Universitaria de Navarra, University of Navarra, Pamplona, Navarre, Spain.