Added Biopsy Information Could Improve Prostate-Cancer-biopsy Grading

By Will Boggs MD

October 02, 2019

NEW YORK (Reuters Health) - Incorporating two pathological features obtainable from biopsies could improve prediction of outcomes and guide treatment choices in men with prostate cancer, according to a new proof-of-principle study.

Invasive cribriform and/or intraductal carcinoma (CR/IDC) are pathological features that independently predict disease-specific survival (DSS) and biochemical recurrence-free survival (BCRFS), but they are not included in current grading systems.

Dr. Geert J. L. H. van Leenders of Erasmus University Medical Center, in Rotterdam, the Netherlands, and colleagues investigated whether incorporation of CR/IDC into the current Gleason score-based grade groups improved prediction of prostate cancer outcomes in their study of more than 1,000 men with prostate cancer who participated in the Dutch part of the European Randomized Study of Screening for Prostate Cancer.

The new cribriform Grade (cGrade) is equal to the Gleason score-based Grade Group (GG) if CR/IDC is present and equal to the GG minus 1 if CR/IDC is absent (for GG2-5). For men with GG1, the cGrade is also 1, except in the rare case of GG1 with concomitant intraductal carcinoma, where the assigned cGrade is 2.

Incorporation of CR/IDC in the cGrade had the most prominent effect in GG2 tumors, 82.6% of which were classified as cGrade1. DSS in these men was not significantly different from that of men with GG1 prostate cancer.

Reclassification occurred in 42.3% of GG3, 48.4% of GG4 and 37.3% of GG5 cases, while only 0.8% (4/486) of patients with GG1 were upgraded to cGrade2 due to the presence of intra-ductal carcinoma, the researchers report in European Urology, online August 19.

The cGrade had significantly higher discriminative value in predicting DSS than did GG (C-index, 0.79 vs. 0.76, p=0.029), nominally better discrimination for metastasis-free survival (MFS) (C-index, 0.79 vs. 0.77, P=0.062), and comparable discriminative value for BCRFS after radiation therapy (C-index, 0.71 vs. 0.72; P=0.2).

The total number of men who fulfilled the Prostate Cancer Research International Active Surveillance criteria for active surveillance would increase from 272 (26.4%) to 356 (34.5%) if cGrade1 was used instead of GG1.

"The cGrade is a simple prostate cancer grade modification with better discriminative values for DSS and MFS than the GG, particularly impacting decision making in men with current GG2 prostate cancer," the researchers conclude.

Dr. Jonathan Epstein from The Johns Hopkins Medical Institutions, in Baltimore, Maryland, who studies prostate cancer and its grading, told Reuters Health by email that "very-low-grade prostate cancers (Grade Group 1 = Gleason score 3+3 = 6)" often do not need treatment.

"Then there are overt higher-grade cancers (Grade Groups 3-5 = Gleason scores 4+3 = 7; 4+4 = 8; 9-10) which definitely need treatment," he added. "However, there is a group of intermediate-grade cancers, (Grade Group 2 = Gleason score 3+4 = 7) of which some need treatment and some may not (depending on whether the patient is older, has co-morbidity, etc.), where pathologists are trying to find out factors on biopsy to tell the favorable Grade Group 2 versus the unfavorable."

"This study is one such attempt. However, it won't be adopted in widespread practice currently as there are too many questions of how the study was done," he added.

"None of the results are surprising," Dr. Epstein said, "in part because cribriform glands are considered together with intraductal carcinoma, which is a markedly adverse finding on prostate biopsy."

Dr. van Leenders did not respond to a request for comments.

SOURCE: https://bit.ly/2ktYfPN

Eur Urol 2019.

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