G9 Crew - interesting article about relative risks for pattern 4+5, 5+4, 5+5

Keep in mind the fortunately very skewed distribution of the three scores: 74% (4+5), 19% (5+4), and 7% (5+5) according to the study's data:

"Of 17 263 eligible patients with GG 5 cancer at biopsy (RP: n = 7208; EBRT: n = 10 055), 12 705 had Gleason 4 + 5, 3302 had Gleason 5 + 4, and 1256 had Gleason 5 + 5 disease."
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Men who choose RT as their primary treatment miss out on knowing if their definitive G score would have been downgraded. The 2017 study I got the following figures from did not look at downgrading within GG 5 (e.g. 5+4 to 4+5.) I think one has a good chance of such a downgrade, given that pattern 4 is less common than 5, and a biopsy is very hit-or-miss when it comes to discerning which pattern is >50% (e.g., I had one 5+5 core (50% cancer) and one 4+5 core (3% cancer) core on biopsy, and was downgraded to 4+5 after my RP.)

Post-RP Grade Group after a Grade Group 5 biopsy:

GG1: 0%
GG2: 6.7%
GG3: 23.3%
GG4: 1.7%
GG5: 68.3% (No change)

Djin

randyd said...
Djin,

I normally follow, and agree with your comments but I'm missing something here. To me, any number at G9 or above pretty much negates the value of doing surgery only to learn that your prostate biopsied at G8. So what? It's still a high risk diagnosis that really isn't going to change anything going forward. Would a downgrade of my G10 to G9 (or even 8) have made any difference at all in treatment progression or current situation? I think that is highly unlikely.

Hi Randy. That wasn't the point of my citing RP statistics. It has nothing to do with treatment choice. When I say "miss out" is is to point out an upside to RT men who are looking at the survival stats for GG 5 in Redwings post: a downgrade (although theoretical) would improve the (statistical) outlook. In other words, if I had chosen RT, I would look at those stats as a G10 guy. For those G10 guys who choose RT, I'm saying that your outlook may be rosier than you might think -- you could actually be a G9 (4+5), like I was, and the chances of that are pretty good. Up- and downgrading stats can obviously be gleaned only on RP men, but the results apply to all men armed with biopsy knowledge.

That's all. The same goes for my pointing out the favorable distribution frequency of G9-10 scores: (4+5) > (5+4) > (5+5) They work in everyone's favor, regardless of treatment.

Whether one chooses RT or RP, we all make our treatment decisions based on the biopsy Gleason score (among other things). The subject of choosing a primary treatment for us G9-10 men is a separate issue we can discuss, but I don't think up/downgrade stats play much of a role, if any, in that choice for us. (The situation may, or may not, be different for G8 biopsy -- one study shows that almost half of those choosing RP are downgraded, which is logical.)

Djin

Post Edited (DjinTonic) : 5/12/2021 2:07:25 PM (GMT-6)