Grade Group 1 Prostate Cancer: A Pathologist's Case for Cancer Classification 'Con' "Presentation" - Gladell Paner
July 24, 2024
At the CAncer or Not Cancer: Evaluating and Reconsidering GG1 prostate cancer (CANCER-GG1?) Symposium, Gladell Paner discusses the feasibility of reclassifying Grade Group 1 (GG1) prostate cancer from a pathological perspective. He acknowledges the debate between histologic features of cancer and the lack of clinical symptoms or metastasis in GG1 cases. Dr. Paner concludes that accepting a borderline tumor entity in radical prostatectomy specimens, with potential for future refinement using molecular data, could be key to resolving the renaming issue.
Biographies:
Gladell Paner, MD, Professor of Pathology, University of Chicago, Chicago, IL
Biographies:
Gladell Paner, MD, Professor of Pathology, University of Chicago, Chicago, IL
Read the Full Video Transcript
Gladell Paner: So I'm going to present if GG1 as a cancer is feasible in pathology diagnosis. So we already talked about this, the pros and cons of renaming GG1. And as Scott said, really the core reason why 80% of pathologists are against renaming is that it has histologic features of cancer. So we have to accept that. And also, on the other side, we also have to accept that GG1 cancer doesn't cause any symptoms. It doesn't have metastasis. So we also have to consider that. So this is really multifactorial, science and patients benefit. So we're stuck in the middle, and I think that's where we should focus. I think we can classify some GG1 that should be criteria-based as a borderline tumor. And how are we going to do that?
So I'm going to present some options. One question is that we have biopsies and radical prostatectomy renaming should only be feasible in a radical prostatectomy specimen where the whole prostate can be examined, as Samson highlighted in the comment section. And in the recent survey by ISUP, half of those who are in favor of renaming would only rename GG1 in radical prostatectomy. So we have to factor that in. So how are we going to create this entity? It has to be criteria-based. So I'll show you a couple of options. For example, if we have an entity in radical prostatectomy, let's say the organ-confined GG1. Let's call it something like acinar neoplasm of low malignant potential.
Or another option, if we want to be more conservative, is this: insignificant cancer. It's really an oxymoron. There's no such thing as insignificant cancer. Any cancer should be perceived with some degree of significance, right? So this absent criteria, what if we rename this as something like acinar neoplasm of low malignant potential in radical prostatectomy? Again, radical prostatectomy. Now the argument here is what about biopsy? So it actually has an impact on the way we call it in biopsy. So if we have a biopsy showing GG1 in one core out of twelve, now we have two options. Either we are undersampling an adenocarcinoma, or we are now sampling this entity that we're describing as LMP, the former insignificant cancer.
So now what for the pathologist? The pathologist has to admit that there's no way for us to call it either cancer or non-cancer. So we have to come up with a noncommittal term, correct, noncommittal term as acinar neoplasm but made up as an acinar adenocarcinoma. So this is some technicalities in pathology, but how are you going to see this in your report? So that report will be the same, basically we are just stating the words acinar neoplasm and all the parameters are there. So in this renaming, there's really no change in the way we grade the risk stratification and the treatment indication, but it will eliminate the cancer scare based on this terminology.
Another issue that was raised is that how are we going to handle it if this one core has higher grade cancer and the other core is just 3. No problem. It's going to be the same because 60 to 70% of prostate cancers are multifocal. And we see this other small concurrent insignificant cancer as a background of this dominant cancer. So it's not really a problem.
So, to me, the key to resolve this renaming issue is to accept a borderline tumor entity in radical prostatectomy only, where the tumor can be totally examined and we can create some criteria. Either the low-hanging fruit is the insignificant cancer, and we can refine this in the future. We can add some molecular data-
Speaker 2: The final one.
Gladell Paner: Yeah, thank you.
Gladell Paner: So I'm going to present if GG1 as a cancer is feasible in pathology diagnosis. So we already talked about this, the pros and cons of renaming GG1. And as Scott said, really the core reason why 80% of pathologists are against renaming is that it has histologic features of cancer. So we have to accept that. And also, on the other side, we also have to accept that GG1 cancer doesn't cause any symptoms. It doesn't have metastasis. So we also have to consider that. So this is really multifactorial, science and patients benefit. So we're stuck in the middle, and I think that's where we should focus. I think we can classify some GG1 that should be criteria-based as a borderline tumor. And how are we going to do that?
So I'm going to present some options. One question is that we have biopsies and radical prostatectomy renaming should only be feasible in a radical prostatectomy specimen where the whole prostate can be examined, as Samson highlighted in the comment section. And in the recent survey by ISUP, half of those who are in favor of renaming would only rename GG1 in radical prostatectomy. So we have to factor that in. So how are we going to create this entity? It has to be criteria-based. So I'll show you a couple of options. For example, if we have an entity in radical prostatectomy, let's say the organ-confined GG1. Let's call it something like acinar neoplasm of low malignant potential.
Or another option, if we want to be more conservative, is this: insignificant cancer. It's really an oxymoron. There's no such thing as insignificant cancer. Any cancer should be perceived with some degree of significance, right? So this absent criteria, what if we rename this as something like acinar neoplasm of low malignant potential in radical prostatectomy? Again, radical prostatectomy. Now the argument here is what about biopsy? So it actually has an impact on the way we call it in biopsy. So if we have a biopsy showing GG1 in one core out of twelve, now we have two options. Either we are undersampling an adenocarcinoma, or we are now sampling this entity that we're describing as LMP, the former insignificant cancer.
So now what for the pathologist? The pathologist has to admit that there's no way for us to call it either cancer or non-cancer. So we have to come up with a noncommittal term, correct, noncommittal term as acinar neoplasm but made up as an acinar adenocarcinoma. So this is some technicalities in pathology, but how are you going to see this in your report? So that report will be the same, basically we are just stating the words acinar neoplasm and all the parameters are there. So in this renaming, there's really no change in the way we grade the risk stratification and the treatment indication, but it will eliminate the cancer scare based on this terminology.
Another issue that was raised is that how are we going to handle it if this one core has higher grade cancer and the other core is just 3. No problem. It's going to be the same because 60 to 70% of prostate cancers are multifocal. And we see this other small concurrent insignificant cancer as a background of this dominant cancer. So it's not really a problem.
So, to me, the key to resolve this renaming issue is to accept a borderline tumor entity in radical prostatectomy only, where the tumor can be totally examined and we can create some criteria. Either the low-hanging fruit is the insignificant cancer, and we can refine this in the future. We can add some molecular data-
Speaker 2: The final one.
Gladell Paner: Yeah, thank you.