I was asked to review it, but decided not to, because I had already reviewed all recent relevant published randomized trials on hypofractionation (see link below) and there was no original research here.
It is worth noting the panel's recommendation:
The German panel said...
There is a growing body of evidence that modern moderately hypofractionated regimens are safe and non-inferior to conventional fractionation in terms of clinical and biochemical recurrence-free survival and late toxicity.
And I think that their caveat is important:
"To restrict the use of moderate hypofractionation to high-end techniques including IGRT and IMRT in carefully selected patients and to adhere to published phase 3 protocols with documented safety and efficacy."
For my last review, which covers an MD Anderson trial too recent to make it into their study,
see:
Hypofractionated radiation therapy using IMRT has a clear advantagePaxton-
What they are talking about
is known as "moderate" hypofractionation. SBRT is referred to as "extreme" hypofractionation, and involves a different set of techniques and practices, as you said. The biggest difference, in my opinion, is intrafractional tracking. Some kinds of external beam technology, like the 3D-CRT technology used in some of those studies are unsuitable for SBRT. I think they are unsuitable for
any kind of hypofractionation.
BTW - Katz and King are working on their 10-year update of patient-reported outcomes for SBRT. That will be the largest and longest study of
any contemporary external beam monotherapy. Don't expect any surprises, although I suspect there will be gradual deterioration of urinary and sexual function as men age (I think the average age at treatment was 70, so these are 80 year old men now).