Five years after the last prostatic carcinoma grading consensus conference of the International Society of Urological Pathology (ISUP), accrual of new data and modification of clinical practice require an update of current pathologic grading guidelines. This manuscript summarizes the proceedings of the ISUP consensus meeting for grading of prostatic carcinoma held in September 2019, in Nice, France. Topics brought to consensus included the following: (1) approaches to reporting of Gleason patterns 4 and 5 quantities, and minor/tertiary patterns, (2) an agreement to report the presence of invasive cribriform carcinoma, (3) an agreement to incorporate intraductal carcinoma into grading, and (4) individual versus aggregate grading of systematic and multiparametric magnetic resonance imaging–targeted biopsies. Finally, developments in the field of artificial intelligence in the grading of prostatic carcinoma and future research perspectives were discussed.

Data from the past 6 years have shown that the presence of any amount of cribriform (or more comprehensively, large acinar cribriform to papillary) pattern of invasive prostate cancer is associated with adverse pathologic features and leads to uniquely adverse outcomes. Sixteen papers and numerous abstracts have reached these conclusions concordantly. Not only does this justify removal of all cribriform cancer from Gleason grade 3, it shows that cribriform cancer has pathologic, outcome, and molecular features distinct from noncribriform Gleason grade 4. Suggestions for accommodating the presence of cribriform cancer into the 2014 Grade Group scheme are proposed.

ISUP (International Society for Urologic Pathology) and WHO adopted prognostic Grade Groups 1 to 5 that simplify prostate cancer grading for prognosis. Grade Group 4 is Gleason score 8 cancer, which is heterogeneous, and it encompasses Gleason score 4 + 4 = 8, 3 + 5 = 8 and 5 + 3 = 8. The comparative prognostic implications of these various Gleason scores had not been studied by urological pathologists after a re-review of slides. Patients with a highest biopsy Gleason score of 3 + 5 = 8 or 4 + 4 = 8 were included in the study. Controls were cases with a highest Gleason score of 4 + 3 = 7 or 9-10. A total of 423 prostatic biopsy cases accessioned from 2005 to 2013 at 2 institutions were reviewed. Clinicopathological findings and followup (median 33.4 months) were assessed. Among Gleason score 8 cancers the cancer status outcome in 51 men with Gleason score 3 + 5 = 8 was marginally worse than in 114 with Gleason score 4 + 4 = 8 (p = 0.04). This was driven by a persistent nonmetastatic (after radiation/hormone therapy) cancer rate of 37% among Gleason score 3 + 5 = 8 cases vs 24% among Gleason score 4 + 4 = 8 cases. Conversely, cancer specific survival at 36-month followup was 97.8% in 3 + 5 cases vs 92.6% in 4 + 4 cases but this was not significant (p = 0.089). Cancer specific survival in the Gleason score 8 group was dichotomized by the presence of cribriform growth (p = 0.018). All Gleason score categories did not differ in the fraction of biopsy cores positive, clinical presentation or pathological findings, including the frequency of Gleason pattern 5, in 70 patients who underwent prostatectomy. Using the most current standards of prostate cancer grading the prognosis is not different in Gleason score 3 + 5 = 8 and 4 + 4 = 8 cancers. This justifies including both in Grade Group 4.