Based on the recent guidelines, should prostate SBRT dose be no higher than 3625 cGy in 5 fractions?

We have delivered prostate SBRT in high volume using 3,800 cGy/4 fx since 2006. The UCSF group has also used this schedule in a large number of patients for a similar time frame. For over a decade prior to that, the exact same dose regimen was used with HDR brachytherapy and published as "safe and effective" in the Journal of Urology in 2004 (Grills et al., PMID 14767279). This HDR study served as our founding prostate SBRT template and we have still not deviated.

This specific dose fractionation...

In the absence of a randomized trial, it is difficult to definitively conclude that higher doses are definitely superior. In addition, it is very likely that the outcomes of SBRT for prostate cancer depends upon the risk group we are dealing with (low risk, favorable intermediate risk, and unfavorable intermediate risk disease), as well as the volume of disease present. It could very well be the case that low-volume disease among favorable risk groups may not necessarily require such high dose l...

I thought I'd update my answer since a lot has changed since 2018, but this is still a good question. The core of my previous answer is still correct, because of two important things:

1. There is a plethora of data at the 36.25 Gy/5 Fx dose that shows it to be effective and of low toxicity.
2. The 36.25 Gy/5 Fx dose is in the flat section past the shoulder of the dose-response curve (above 90-95%). This means that dose increases will likely have little change in response.

However, we have changed our ap...

I think that 36.25 Gy to the PTV provides a very reasonable balance between risks and benefits. However, I’m not sure if this prescription alone is sufficient to maintain the excellent control rates that standard hypofractionation yields. Currently, I utilize a treatment based on PACE-B (van As et al., PMID 39413377), which includes a CTV boost to 40 Gy/5#.

PACE-B (SBRT vs. DE-EBRT) found that SBRT (36.25 Gy to PTV + 40 Gy to CTV) was non-inferior to DE-EBRT (78 Gy/39#). In contrast, NRG GU005 (S...

As this thread has been revived, I will weigh in. As summarized nicely by Krishnan Patel, the RCT evidence supports 40 Gy/5 fx as non-inferior to standard non-SBRT regimens, with a slight increase in side effects. Thus, that is the standard in my view until we have new RCT evidence.

Focal boost is discussed elsewhere, and I have commented on the pros and cons of extrapolating FLAME results to SBRT (tl;dr: I do it).

I love the idea of combining focal boost with a lower dose to areas not suspicious ...