Pathology Question: Percentage of Gleason grade per core?

[LemonPan]

Hello again.

I have a question about the percentages listed on the biopsy pathology report. What does the percentage of tissue with carcinoma and Gleason 4 signify?

I realize that the biopsy only takes a small amount of tissue. So the samples are not the whole story. I’m just curious about what they might mean.

On my husband’s report, the following percentages are listed.

For the Gleason 3+4 Core

The percentage of tissue with carcinoma is 40%

The percentage of Gleason grade 4 and/or 5 is 25%

For the Gleason 4+3 Core

The percentage of tissue with carcinoma is 12%

The percentage of Gleason grade 4 and/or 5 is 60%

This is on our list to ask the doctor but his appointment isn’t for two weeks. I thought perhaps you folks might be able to shed some light on this.

As always, thank you!

[Tall_Allen]

In the first core, it means that 40% of the entire core has cancer in it; 60% of that core has no cancer in it. The core is GS 3+4. So, 75% of the cancer in that core is Gleason pattern 3; 25% is Gleason pattern 4.

In the second core, which is more important, it means that 12% of the entire core has cancer in it; 88% of that core has no cancer in it. The core is GS 4+3. So, 60% of the cancer in that core is Gleason pattern 4; 40% is Gleason pattern 4.

There is no Gleason pattern 5 in either core.

Here are some questions to ask:

prostatecancer.news/2017/12...

For "unfavorable intermediate-risk" the therapy with the best cure rate is brachy boost therapy. However, balancing side effects, SBRT and HDR brachytherapy as monotherapies are also good options. You have to talk to a Radiation Oncologist (RO) who is an expert at those specific therapies (your urologist or a "generic" RO will probably be useless).

prostatecancer.news/2018/10...

[LemonPan in reply to Tall_Allen]

Thank you! I've printed out those questions.

The percentage of gleason in each core piqued my interest. I wondered why it was noted that 60% of the core was Gleason 4. Would a doctor look at that differently than if, let's say, the sample was 80% gleason 4.

The same goes for the percentage of cancer in the cells itself. It caught my attention that the first had 40% carcinoma and the second had 12%.

I realize I might be overthinking this. I just found it interesting.

[Tall_Allen in reply to LemonPan]

While much of its utility may be irrelevant in your husband's situation, it is good pathology practice to report all 3 percentages in all biopsy reports.

It can be very important for men on active surveillance. A GS 3+4 with 5% pattern 4 is still a good candidate for active surveillance; 45% pattern 4 is a poor candidate.

The % of the core with cancer may be a bigger risk factor if, say, all positive cores were full of cancer. That suggests that the prostate itself, and not just the random cores, has a lot of cancer in it. On the other end, for active surveillance, there is a "very low risk" category that is, in part, defined by "no more than 50% cancer in any core."

There is also a role in risk stratification and treatment decisions for the % of cores that have any cancer in them. For example, if his highest Gleason score were 3+4, he would nevertheless be categorized as "unfavorable intermediate-risk" if more than half of the cores were positive. It is also part of the definition of "very low risk." Some use it to define candidates for focal ablation.

[LemonPan in reply to Tall_Allen]

Ah! This answers my question. Thank you!

I found it interesting to learn that "low volume" vs "high volume" refers to how many of the cores are positive. I believe my husband is low volume, with 2 out of 14 cores positive. Before I read that, I wrongly assumed that the size of the tumor seen on the MRI would dictate whether it was low or high volume.

[Tall_Allen in reply to LemonPan]

The MRI is a much better indicator of tumor volume than the % positive cores. Biopsy cores may randomly hit or miss the tumors.

[LemonPan in reply to Tall_Allen]

Really interesting.

Does missing the tumor apply with a MRI-targeted biopsy?

[Tall_Allen in reply to LemonPan]

Yes, but less than if completely random. They should take at least 4 cores from regions with high PIRADS scores. Saturation biopsies are even more thorough.

[LemonPan in reply to Tall_Allen]

That's what they did for my husband. They sampled 5 cores from the one area with the PIRADs 3. The rest from random areas throughout the prostate. The cores with the cancer were from the PIRADs 3 lesion. Everything else came up benign.

Thanks for chatting about this with me!

[CarverD]

Good morning LP. Can't add anything to T_A's comments as he totally covered your questions. If your husband is thinking about HDR Brachytherapy as either a mono therapy or in conjunction with SBRT feel free to give me a shout. I was treated with HDR-BT on 10/1 and 10/8/20 and am quite pleased with the end results.

[LemonPan in reply to CarverD]

Thank you! I really appreciate that!