In Reply to Yamazaki Et Al.

We thank Yamazaki et al for their interest 1 Aibe N Masui K Yoshida K et al. In regard to Musunuru et al. Int J Radiat Oncol Biol Phys. 2022; 113: 229-230 Google Scholar in our work. 2 Musunuru HB Cheung P Vesprini D et al. Gantry-based 5-fraction elective nodal irradiation in unfavorable-risk prostate cancer: Outcomes from 2 prospective studies comparing SABR boost with MR dose-painted HDR brachytherapy boost. Int J Radiat Oncol Biol Phys. 2022; 112: 735-743 Google Scholar Given that our study 2 Musunuru HB Cheung P Vesprini D et al. Gantry-based 5-fraction elective nodal irradiation in unfavorable-risk prostate cancer: Outcomes from 2 prospective studies comparing SABR boost with MR dose-painted HDR brachytherapy boost. Int J Radiat Oncol Biol Phys. 2022; 112: 735-743 Google Scholar compared patients enrolled in 2 different prospective studies, it is difficult to draw a definite conclusion about outcomes due to differences in unknown variables. As pointed out by the authors, the rate of 5-year biochemical failure was higher in the high-dose-rate (HDR) brachytherapy boost cohort despite having a higher eqivalent dose at 2 Gy per day (EQD2). This could be due to either a difference in the effective dose to gross tumor volume or the gross tumor volume across both studies. In addition, the presence of nonregional disease at the time of diagnosis, which might not have been captured using conventional imaging, could also potentially contribute to these differences in biochemical failure. 3 Hofman MS Lawrentschuk N Francis RJ et al. Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA): A prospective, randomised, multicentre study. Lancet. 2020; 395: 1208-1216 Google Scholar