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Gleason scores 3-4

Tuesday 31 July 2012

Gleason scores 3-4

These low-grade tumor scores were assigned by members of the ISUP consensus panel occasionally on transurethral resection specimens (TURPs) and in multifocal low-grade tumors within radical prostatectomy specimens.

In contrast to Gleason’s diagram and text, the consensus was that cribriform patterns are not allowed within Gleason pattern 2.

It is now accepted that Gleason score 2-4 should not be assigned to cancer on needle biopsy for several reasons:
- poor reproducibility even amongst experts;
- poor correlation with prostatectomy grade with almost all cases showing higher grade at resection;
- a diagnosis of Gleason score 3-4 may misguide clinicians and patients into believing that the patient has an indolent tumor.

The major limitation of rendering a diagnosis of Gleason score 4 on needle biopsy is that one cannot see the entire edge of the lesion to determine if it is completely circumscribed.

Consequently, most of the lesions that appear to be very low grade on needle biopsies are diagnosed by urological pathologists as Gleason score 2+3=5 or 3+2=5.