Study for Very High Risk (VHR) PCa, comparing EBRT+ADT with EBRT+BT+ADT

This study just arrived in my inbox today. It's specifically for Very High Risk cases (as mine was). I find it interesting since this is an ongoing discussion for many types of prostate cancer. This is very specifically focused on a quite small subset of the PCa community.

From the article:
"In this VHR PC cohort, no difference in clinically meaningful outcomes was observed between EBRT alone with ≥ 24 months of ADT compared with EBRT+BT with ≥12 months of ADT. Comparative analyses in men treated with intensified systemic therapy are warranted."

External Beam Radiotherapy With or Without Brachytherapy Boost in Men with Very High-Risk Prostate Cancer: A Large Multicenter International Consortium Analysis.

DjinTonic said...
... for high-grade/high-risk prostate cancer that appears to be localized on workup, surgery--followed by RT/ADT if required--remains a good treatment option... I still would want both big guns: RP + RT.

You hit the nail on the head Djin. My MRI indicated the cancer to be organ confined, however surgeon found extensive local spread. The main advantages of primary RP in VHR cases remains 1) accurate pathology, and 2) viable adjuvant or salvage therapy.

They seem to redefine the difference between high risk and VHR every few years. I still cannot find a current definitive chart of VHR features, so generally I stick with stage T3b or 4, Gleason 8-10, primary grade 5 or >4 cores grade 4 and PSA >20.

It was a truly hectic couple of years, but now being NED for over 4 years I'm glad I threw everything at it early on.

Hi StephanieAndEric. I would call the docs' attention to the study and let them decide what weight and applicability it has to your husband's case. I would agree that his is a very serious situation and--if this were me--I would seek the opinion(s) of a team at a (or another) prostate cancer center of excellence, especially if you are getting differing/contradicting opinions now. There are a number of these centers around the country, so there should be at least one not far from you.

Looking at your other thread, I now see you have had expert opinions. At a certain point you need to distill all the info you have gotten in order to come to a treatment decision.

A single study does not determine standard of care, which, for the high-risk cases studied, is not settled. For my layman's thoughts, I would want HD brachy and EBRT for such an extensive G10 with such a high tumor burden within the prostate. Further imaging seems like a very good idea, and would most likely help with any consults at another center.

Surgery could have an advantage if the rectal wall involvement is small. Also, your husband's might be case where debulking the large amount of cancer via a RP could improve treatment outcome.

With the advent of PSA screening confirmed Gleason 10 (5+5) is becoming rare. (I had a G10 biopsy, but was downgraded to G9 (4+5) after surgery). However, with such an extensive amount of 5+5 on biopsy, I think your husband may be a true G10. It's hard enough to capture data for G9 patients in studies, and, as his doc mentioned, it's not clear whether study data based on G8 and 9 men is valid for true G10 men. I think many--if not the majority--of G10-biopsy men getting radiation in the study would have been downgraded to G9 post-op had they had surgery.

A problem with studies on high-risk/high-grade men is that, fortunately, we are not the typical cases, and are represented by low numbers, which, statistically speaking, translate to low "strength" or validity. The smaller the number of study participants, the weaker the strength of the evidence, or put another way, the bigger the difference you need to see to prove there is a difference between the study arms. Also any single study may be called into question for a variety of reasons, which is why it takes many studies over many years to set best practices for treatments.

Djin

Duck2 said...
So what was this study trying to measure with two different durations of ADT?

"This cohort study from 16 centers across four countries included men with VHR PC treated with (i) dose-escalated EBRT with ≥ 24 months of ADT or (ii) EBRT+BT boost with ≥ 12 months of ADT. "

I don't see a Full Text, but this may have been a retrospective study, and perhaps men who do not get BT boost are generally given 2 or more years of ADT whereas a good number of men who get the BT boost get only 1-2 years of ADT. In other words, they did not set up a prospective study, but are simply describing the treatment given and collecting data. Perhaps the BT boost would have shown better results than no boost if it had always been coupled with ≥ 24 months of ADT (?).

Djin

Post Edited (DjinTonic) : 10/12/2022 5:12:50 AM (GMT-7)

Duck2 said...
Is the result of the study the different radiation treatments or the different length of ADT? I don’t believe many are recommending as little as 12 months ADT these days in VHR.

Quoting from the Abstract:

"In this VHR PC cohort, no difference in clinically meaningful outcomes was observed between EBRT alone with ≥ 24 months of ADT compared with EBRT+BT with ≥12 months of ADT. Comparative analyses in men treated with intensified systemic therapy are warranted."

As I mentioned, I haven't seen the Full Text. I assume they looked at the data available, which was combination therapy in both cohorts. I don't know what percentage of men received as little as 12 months ADT--perhaps it was very few. We can parse out the contribution of RT vs that of ADT, and, since no meaningful difference was observed, I don't think it matters. The takeaway might be that men for whom these treatment modalities are recommended can choose between (a) a somewhat shorter course of ADT with an increased risk of radiation toxicity and second primary cancers or (b) longer ADT with the standard (low) risk of second primary cancers. There may not have been sufficient numbers to make cohorts with equal lengths of ADT therapy.

Djin