Why is volume of the cancer not used?

But you are at a single point in time where decisions are being made for treatments. If one has 5 times the amount (volume) of the other, that means nothing to you? I mean sure, other information is helpful, history is good information, but why is 5 times the volume of the other meaningless? The system seems invented from past when imaging was not available is the problem. We need better solutions, here is something that can be worked in, doesn't mean we don't count history but no ignoring it (as seemingly suggested) and staying the status quo is not a good strategy going forward. Science progresses, here is a real easy fix.

The whole bases of Gleason is the doubling time of historic growth
doubling time..big difference in 3-4
4-3
4-4

You are doing what the other poster suggested comparing apples to oranges. I am NOT comparing 3 to 4, or 4 to 3, or 4 to 4+. I am comparing 4 to 4 and the volume. Doubling time may not be possible to calculate. Ignore volume so a doubling time can be calculated is what I think you are saying, again that is good information but here is a simple fix to make the system relevant today. Then in your example, are you talking doubling time of the 3 or the 4 since you mix 3 and 4 and I am comparing only 4 to 4?

If the total amount of 4 is higher I believe the tumor grade is higher.. the Gleason score is only part of the tumor grade.

I never hear volume outside people who have high volume 3, only time I hear "volume". Hopefully somebody is looking into these things, I just brought it up because I never hear about this topic at least as I have laid out, who knows.

Thanks for inputs and everyone for inputs appreciate the thoughts.

I agree. I think volume should rank up there with number of cores positive but even that metric took a while to take hold.

I personally think AI should make questions like this moot but it needs data to develop models and that may take a few years. The technology is there we just need the humans to agree on frameworks about storing peoples medical records anonymously for research efforts and the like. Not going to happen overnight unfortunately,

Thanks @ozelli, one must admit that a system as is, one that allows 5 times as much Gleason 4 to be called less serious than the one with only 20% of the Gleason 4, must be called totally broken. That x+y gleason stuff is antique, I mean in past it seemed a way to quickly be quantitative but no longer. I understand how and where it came from but still, as it is it makes significant gross errors by the way it is done. It is a system that allows 5 times as much gleason 4 to pass as less serious than only 20% of the gleason 4. That has huge ramifications. They need to make some corrections. I guess it won't happen soon, so yeah what can we do? Not much as individuals perhaps.

Another way to do it, is look at how much of the prostate is at the highest Gleason. So lets say for ease a 50 cc prostate.

Case 1 is 1 cc of Gleason 4 and prostate is 50 cc, so (1/50)*100 = 2 % of the prostate is Gleason 4.
Case 2 is 0.2 cc all Gleason 4, so (0.2/50)*100 = 0.4% of the prostate is Gleason 4.

Which is worse, 2% or 0.4% of the prostate as Gleason 4?
Unfortunately case 1 is graded 3+4 so they claim it is not as bad. I say that is just plain nonsense by any sense of thinking.

Not important to review but here are the cases again:
*Case 1 has a 3+4 lesion at 2.1 cc, the 4 at 49% and the 3 at 51%. So that means the part that composes 4 is about 1 cc total. Total count of 4 = 1 cc.
*Case 2 has a 4+4 lesion but only about 0.2 cc. Total count of 4 = 0.2 cc

Volume may not be that important. Some no longer want to call irregular cells in the prostate "cancer", until it forms a lesion of growing cancer.

Well I am talking about Gleason cells graded as 4 cells by a pathologist, and comparing two cases. I am not sure what irregular cells you are talking about, I have not mentioned any kind of irregular cell.