EAU 2021: How to Quantify Biopsy Gleason Grade 4 for Active Surveillance

(UroToday.com) Dr. Geert Van Leenders of the Netherlands provides the Pathology perspective on quantifying Gleason pattern 4 for active surveillance (AS). First, he highlights the fact that Gleason pattern for disease is a heterogeneous subset. Historically Gleason pattern 4 was a single entity – but recent research has demonstrated that Gleason pattern has multiple histologic subsets. These include fused glands, ill-formed glands, glomeruloid histology, and importantly intraductal (IDC) and cribriform patterns. We now know that separating out IDC/cribriform pattern 4 is critical and has oncologic implications. As seen in the K-M curve below, when GG2 disease is stratified by the presence/absence of IDC/cribriform pattern, men with GG2 without these features have similar outcomes to men with GG1 disease. But, men with those features have much worse metastases-free survival.

The percentage of pattern 4 also matters. Currently, GG2 includes men with secondary pattern 4 that can range from 1-49%. Yet, realistically, these patients are not equal. This is demonstrated by Sauter et al. (EU 2016), where PSA recurrence-free survival was directly, incrementally related to % pattern 4 in men with GG2 prostate cancer.

But, while the percentage of pattern 4 matters, there is no established cutoff for AS eligibility. Some studies have suggested using 10%, but there is no data to support this.

Indeed, ~50% of men with cribriform-negative GG2 prostate cancer on biopsy will have a cribriform pattern or higher GG on final prostatectomy pathology. So, how can we identify men with a potentially higher risk of adverse pathology? Prior work by his own group suggests that MRI PIRADS 5 lesion, higher percentage pattern 4, age, and cumulative tumor length on biopsy were predictors.

His take-home for the talk is seen below:

Leenders 3.jpg

Basically, if there is cribriform/IDC present on biopsy – patient should NOT be recommended for AS. However, if cribriform/IDC is absent on biopsy, patient can be considered for AS – but evaluation of predictive factors (% pattern 4, mpMRI, tumor volume, and patient preference) should be taken into consideration.

Presented by: Geert Van Leenders, MD, PhD, Erasmus MC, University Medical Center, Rotterdam, Netherlands

Written by: Thenappan (Thenu) Chandrasekar, MD – Urologic Oncologist, Assistant Professor of Urology, Sidney Kimmel Cancer Center, Thomas Jefferson University, @tchandra_uromd on Twitter during the 2021 European Association of Urology, EAU 2021- Virtual Meeting, July 8-12, 2021.

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