Gleason grading: past, present and future

Abstract

In 1966 Donald Gleason developed his grading and scoring system for prostatic adenocarcinoma. This classification was refined in 1974 and gained almost universal acceptance, being classified as a category 1 prognostic parameter by the College of American Pathologists. Modifications to the classification were recommended at a conference convened by the International Society of Urological Pathology (ISUP) in 2005. This modified classification has resulted in a significant upgrading of tumours, although some studies have shown a greater concordance between needle biopsy and radical prostatectomy scores when compared to classical Gleason (CG) grading. The ISUP consensus conference recommended that for needle biopsies higher tertiary patterns should be incorporated into the final Gleason score, and this has been correlated with biochemical failure, tumour volume and mortality. Recently the validity of including cribriform glands as a component of Gleason pattern 3 has been questioned and it has been recommended that all tumours showing cribriform architecture should be classified as Gleason pattern 4. The recommendations arising from the 2005 Consensus Conference were largely unsupported by validating data, yet this new grading system has achieved widespread usage. It is unfortunate that recent suggestions for further modification are similarly lacking in supporting evidence. In view of this it is recommended that the Modified Gleason Scoring Classification should continue to be utilized in its original (2005) format and that any future alterations should be implemented only when mandated by tumour-related outcome studies.

Gleason inflation 1998–2011: a registry study of 97 168 men

“…Almost 50 years have passed since the introduction of the Gleason grading system and it is still one of the most powerful prognostic and predictive factors in prostate cancer [1][2][3][4]. In 2005, Gleason grading underwent its first major revision at an International Society of Urological Pathology (ISUP) consensus conference [5].…”

Prostate Cancer Registries: Current Status and Future Directions

“…Third, population-based registries usually include patients diagnosed over a long time period. Therefore, changes in staging and grading classification systems, as well as modifications for coding systems, can result in misclassification of some variables [112]. These issues should be considered when planning investigations using these registries.…”

Proposal of Gleason-like grading system of canine prostate carcinoma in veterinary pathology practice

“…An important feature of the Gleason grading is that it does not rely on detailed assessment of nuclear morphology, but it assigns numerical grades (1)(2)(3)(4)(5) based upon the architectural patterns of the tumour that are best evaluated at low power magnification. Patterns 1, 2 and 3 represent tumours that most closely resemble normal prostate gland, and patterns 4 and 5 are tumours showing increasingly abnormal glandular architecture (Gleason, 1966).…”