Issues in Uropathology-Tertiary Grading of Prostate Cancers

Recent articles in the surgical pathology literature have investigated the utility of incorporating tertiary grades into the traditional two-tiered Gleason's grading system. A tertiary pattern is defined as <5% of total tumor mass by visual inspection.

Table 1 illustrates how a tertiary pattern of 4 or 5 may portend a poorer prognosis for selected cancers. This data was obtained after comparing the results of grading and scoring on needle core biopsies with the final radical prostatectomy specimens.

Patients with a Gleason score of 4+4=8 on one or more cores with a pattern grade 3 in other cores should be given a final Gleason score of 4+4=8 instead of 4+3=7. These patients are more likely to have a higher stage and grade on radical prostatectomy, comparable to a pure Gleason score of 4+4=8. Each core should be assigned a separate Gleason score, especially in cases with a high Gleason score with cancer on at least 1 core.

Table 2

Gleason Score	Tertiary Pattern	Behavior
3+4	5	More organ confined, less LN mets
4+3	5	Less likely organ confined, more LN mets
4+4	5	No difference from 4+4