In-room imaging and MR planning

b. HDR BT as boost

Trial

N Design

Results

RTOG 03-21

125 45 Gy EBRT + 19 Gy HDR boost

Grade ≥ 3 GU or GI toxicity was 2,6% at 18 months Biochemical failure lower in the HDR group (29 vs. 61%, p = 0.0024), although OS was similar, at 8 years HDR boost resulted in a 31% reduction in the risk of recurrence (p = 0.01). Long term toxicity was identical at 7 years.

Canadian trial

104 66 Gy@2 Gy EBRT vs. 45 Gy + 35 Gy HDR boost

Mount Vernon Cancer Centre

220 55 Gy@2,75 Gy EBRT vs. 35,75 Gy + 17 Gy HDR boost

MSKCC

229 45 – 50,4 Gy EBRT + 17,5 Gy HDR boost

7-year PSA relapse-free survival was 81%

HDR BT boost after a shortened course of EBRT appears to be an elegant way to escalate the dose, while also exploiting the apparent sensitivity of PC to higher dose rates and shortened overall treatment time