RP vs RT in High Risk

Interesting read. I think this has not been posted here. Sorry if this is a repeat. Not sure how to make is an active link.

https://pubmed.ncbi.nlm.nih.gov/34555930/

I remember this study. It has the fundamental problem that many studies have--it looked at 5-year mortality rates. Also, I believe the men had EBRT alone, whereas many high/very-high risk men are getting it with a brachy boost.

Yesterday I was excited to find a study that looked at the (very good) low rates of BCR for > 1000 men who were pT2 R0 (negative margins) after RP (my cohort). I tossed it when I saw that the mean follow-up was less than 3 years post-op. We need 15- and 20-year studies. Everyone wants Big Data now, and we have the means to collect and analyze it. My uro said that there is still reluctance about the privacy question--I replied that these data banks can be made completely anonymous, forgoing even patient initials (which is what the sponsors of clinical trials get). RP and RT have been around for RP treatment for some time now, but we don't have bottom lines.

You would think we'd have superb comparative statistics about primary treatments broken down by staging at the time of diagnosis, but we don't. A confounding issue is that RT methods keep changing in many regards: type of RT, fractionation, +/- ADT, etc.

Djin

EBRT as a monotherapy for high risk PCa? I stopped reading at that point.

Brachytherapy boost is what is needed to treat high risk cases.

https://www.medpagetoday.com/hematologyoncology/prostatecancer/71560

In the Medpage Today article ” But these differences did not remain statistically significant beyond 7.5 years..

It is pretty clear that obtaining longer term data on newer treatments is difficult at best. It has reached the point where there are recent studies proving anything that anyone wants to consider or justify. The problem is with the data just like with Covid 19. Twenty years of incomplete and flawed data acquisition does not make for accurate conclusions nor do studies of 100 men.

I got worn out trying to justify ART with or without ADT based on the myriad of conflicting publications and studies that have been done. No sooner than I had something figured out, I would become aware of another study that conflicted with the previous study or would sneak in “not valid for high risk cases” at the end.

The therapies available now have improved quite a bit over what was available in 2010-2016 (treatment dates of cohort). Using 10-20 year data to choose a therapy means choosing a therapy that is 10-20 years old. Things like continuously guided radiation through MRI (Mridian) wouldn't be considered.

It's the nature of the beast.

The definitive study you want almost never exists. It's hard to have enough participants in medical study to permit the kind of fine-grained analysis we want, and over time the number of participants in a study declines as they die or otherwise drop out. A researcher is never going to wait 15 or 20 years before publishing results, either. If one therapy seems more effective over five years compared to another, isn't that good enough for you to make a decision?

Studies about new treatments are published at regular intervals, be it 3-, 5-, 12-, 15-, 20-years or whatever. The more a newer treatment departs from proven treatments, the longer the period for which I would want to see outcome data. Take fractionation. Researchers are still working out the optimal balance between outcomes vs. convenience & cost. The outcomes are several: oncological control (BCR and recurrence), short- and long-term toxicities, second primary cancer risk, potency, etc.

And it wasn't until late last year that MSK researchers published this study regarding total dosage:

Predictors for Post-treatment Biopsy Outcomes after Prostate Stereotactic Body Radiotherapy

"Conclusion
Based on two-year post-SBRT biopsies, excellent tumor control was achieved when dose levels of 40 Gy or higher were used. Standard SBRT dose levels of 35–37.5 Gy were associated with a higher likelihood of a positive post-treatment biopsy. Two-year positive post-treatment biopsies pre-dated the development of PSA failure in the majority of patients."

If I was diagnosed and chose SBRT as my primary treatment and then came across the study, I'd want to have a serious discussion with my RT before my treatment. Perhaps the doc would say "OK, but there's a trade-off: better oncological control means an increased rate and seriousness of toxicities. Or perhaps "OK, but the study involved only 257 cases across the range of dosages--can't say for sure because we need more data, more studies. Or perhaps "OK, we can go to 40 gy, but your risk of a second primary cancer may go up--we don't know."