What is the clinical significance of a Gleason pattern 4 or 5 tumor found on a prostate needle core biopsy? What impact does a Gleason pattern 4 or 5 tumor have on the prognosis after radical prostatectomy?

Abstract

The Gleason system of prostate cancer is based on the architectural patterns.¹ The primary (predominant) and secondary (second most prevalent) patterns are recognized and assigned a grade from 1 (most differentiated) to 5 (least differentiated). Prostate cancer is noted for its multifocal occurrence of different Gleason grades. Likewise, it is not uncommon to observe more than one histologic pattern in a single mass as a greater amount of tissue is available with a radical prostatectomy specimen than a biopsy. Each tumor is given a score as the sum of two grades of these patterns. If the third most common pattern is of a lower Gleason pattern, it can be ignored. If a higher-grade component (Gleason pattern 4 or 5) is found, its presence must be reported because the tertiary higher-grade component worsens the pathologic stage of otherwise typical Gleason scores 5, 6, and 7 carcinomas and is associated with a higher PSA recurrence rate. With regards to a pattern 4 or 5 carcinoma observed in a prostate needle core biopsy, its presence should be reported as a secondary or tertiary component.

Gleason “pattern” and “grade” are frequently used interchangeably, and Gleason “score” and “sum” are synonymous.