Whole pelvic salvage radiation + short-term ADT improves oncological results

[Tall_Allen]

I know this has been posted before, but I wanted to add some comments. It's often a good idea, but not always.

pcnrv.blogspot.com/2018/10/...

[tallguy2]

Thanks for posting this!

[E2-Guy]

Thank you Allen...you are a wealth of information!

[packfan]

Thanks again TA for these types of postings.

[Blackpatch]

Thank you for posting this. Why do they use nadir + 2 as reoccurrence definition, when the men undertaking SRT will be using an absolute PSA of 0.2 as the BCR definition?

Also, do you know if they have reported on the results for sub-populations such as SVI etc? I guess the absolute numbers of SVI men (15% in this study, I think I read) may be too small to allow meaningful analysis....

In any event, this strong result plus the recent report out of Italy indicating high eSRT success rates with a similar treatment protocol, certainly gives more confidence that the dangers of radiation damage from eSRT may well be worth taking - is that how you see it too?

Stuart

[Tall_Allen]

Good question! They decided to use nadir+2 because, in examining the data, they found that it maximized the correlation with clinical progression. Remember, that for the men in this study, salvage radiation represented the last chance for a cure, so they wanted a definition of biochemical failure that left no doubt that the last ditch effort had failed.

There will be more analyses of the data set down the road.

Note the caveats in the last paragraph. Men with low PSA and low grade, and men in whom positive margins fully explain the rise in PSA may not need to risk the extra toxicity.

[PGDuan]

Hi Tall_Allen - Thanks very much for sharing this. I am about to start EBRT TODAY and I just saw this. My current Stanford RO's plan is for 70 Gy to the prostate bed, and approximately 50 Gy to the 2-3 pelvic nodes that were identified as avid after RALP in August (post-surgery PSA 4.5, down from 11.8 at diagnosis). My RO previously noted my RT is technically "adjuvant" versus "salvage", but I'm not sure it would make much difference. Already on Lupton + Zytiga.

Regardless, I'm running this article by them for their perspective and to confirm the field is wide enough. I'm feely very healthy right now so want to be as aggressive as possible given the potential curative result.

Thanks again

[Tall_Allen in reply to PGDuan]

There's a little confusion. They are probably NOT just treating the 2-3 pelvic nodes found to be cancerous - they are probably treating ALL pelvic LNs (+the prostate bed). I think you understand this based on your comment about the size of the radiation field. They may want to boost the dose to those known sites of cancer, however (depending on whether it's safe to do so).

[PGDuan in reply to Tall_Allen]

Hi Tall ALLEN,

Yes, thanks again for the clarification. My RO confirmed the same.

[Spaceman210]

Hi Allen, do you happen to know why the prostate bed is not routinely biopsied for recurrence concerns vs. just whacking with radiation, similar to the way the gland itself was prior to RP when they did not know the precise glandular location? Is the bed anatomy too thin and spread out, or ?

[Tall_Allen in reply to Spaceman210]

That's right. it is difficult to biopsy the loose tissue of the prostate bed and there is a lot of territory to cover. They can biopsy if a site is found on an mpMRI. However, they still have to treat the entire prostate bed to get all the smaller bits of cancer that can't show up (just as for primary treatment they have to treat the entire prostate and not just the places that show up on a biopsy).