Low Gleason score prostatic adenocarcinomas are no longer viable entities

Abstract

Gleason scoring is the most powerful predictor of the behaviour of prostatic adenocarcinoma. It was devised more than 30 years ago and is used by pathologists worldwide. However, advances in immunochemistry and the understanding of the biological potential of some tumours have made the diagnosis of tumours of grades 1 and 2, and hence low score (2-4), a rarity. It is suggested that Gleason score 2(1 + 1) tumours, if they do exist, are so rare and so benign that they are a redundant entity and should not be identified as a malignancy. Similar problems revolve around the diagnosis of Gleason score 4(2 + 2) tumours and the criteria for their diagnosis are difficult to evaluate and revolve around reference to the score 2(1 + 1) lesion. The continued presence of low-grade tumours in the Gleason grading system leads to diagnostic confusion, potential error and, more importantly, confusion for patients diagnosed with score 6(3 + 3) tumours. I suggest that Gleason grade 1 (and therefore scores of 2 and 3) should be removed from the Gleason grading system. Gleason grade 2 (and therefore score 4 and 5) tumours require serious re-evaluation if they are to remain clinically useful diagnoses.