No prostate, no problem.

Why should a history of prostatectomy keep a man from enjoying stereotactic body radiation (SBRT) as an adjuvant treatment option? The authors of this phase 1 trial sure don't think it should. Men who merited post-prostatectomy adjuvant radiation due to positive margins (n=15) or a pT3 tumor (n=21) were enrolled in this max-tolerated dose finding study, with dose-limiting toxicity defined as grade 3+ Gi or GU toxicity within 10 weeks. The first six patients received 3.6 Gy x 15 to the prostate fossa, the second six 4.7 Gy x 10, and the final twelve 7.1 Gy x 5. Of note, everyone was treated with full bladders and fiducials with at least MV or KV alignment daily, and those in the 5-fraction arm were aligned with daily cone-beam CT. And now for the big reveal: the rate of acute grade 3+ toxicity across all arms was 0%. As anticipated, most grade 2 toxicities occurred in the first two weeks and diminished by week 10. TBL: Prostate fossa SBRT is coming to a phase 2/3 trial near you. | Ballas, Int J Radiat Oncol Biol Phys 2019