Optimal SBRT dose

[Tall_Allen]

40 Gy in 5 treatments looks pretty good. Coincidentally, that's the dose I had

pcnrv.blogspot.com/2019/01/...

[tucker_man]

Good info. Just so I'm clear, when they talk about the dose for the different kinds of EBRT, they cite total dose for the entire course of treatment, correct? So while you get less dosage overall with SBRT, you're getting a stronger per-session dose than IMRT, which is closer to 80 Gy over 40 sessions?

[garyi in reply to tucker_man]

That's correct, tucker.

[Tall_Allen in reply to tucker_man]

You are getting a higher dose per session. But they aren't directly comparable. 40 Gy in 5 treatments (8 Gy per treatment) is biologically equivalent in its cancer-killing power to 115 Gy if delivered at a rate of 1.8 Gy per treatment.

[schwann240]

Thanks for the post, Allen. I had 35gy with Katz. At the time, I never discussed with him the various dosage options and their ramifications. Too bad ...

[Tall_Allen in reply to schwann240]

Actually, Katz takes a slightly different approach. He gives a higher dose (around 37 Gy) to the prostate itself and very low dose out to the margins to lower toxicity. So his average dose is 35 Gy. Every RO has his favorite techniques. With 10 years of data now, his biochemical recurrence-free survival is excellent in favorable risk patients

[AlanMeyer Moderator]

> Coincidentally, that's the dose I had

Ain't it great when hindsight and foresight coincide?

Thanks for the info in the blog post.

Alan

[Moespy]

Allen, Thanks for sharing this. Was it mentioned whether ADT was concurrently used with the patients in this study? If ADT was used it would be interesting to learn the timeframes that the ADT was on and/or off during the study.

Jim

[Tall_Allen in reply to Moespy]

ADT was never used.

[Moespy]

Allen, Do you think that the doses in this study would be also applicable to BCR patients with lymph node only involvement?

Jim

[Tall_Allen]

No - totally different situation

[Moespy]

Thank you for the responses!

Jim