For prostate cancer patients undergoing an HDR boost, what constraints do you use for hypofractionationated EBRT?

A randomized trial in Canada was started comparing IGRT to 78 Gy/39 Fx or 60 Gy/20 Fx vs 37.5 Gy EBRT in 15 fractions with 15 Gy x 1 HDR boost (CCTG PR15/NCT01982786).

In their initial publication Vigneault E et al. Clinical Oncology 2018 they have constraints listed in Table 1 and I'd suggesting us...