Prostatic Adenocarcinoma: A Grading from Gleason to the New Grade-Group System: A Historical and Critical Review

The introduction of the Gleason grading system revolutionised prognostic parameters and determination of patient treatment regiments for prostatic adenocarcinomas, and has become synonymous with prostate cancer, almost universally applied in clinical settings to predict radical prostatectomy specimen findings, potential biochemical failure, local recurrences, lymph nodes or distant metastases in patients not receiving any treatment as well as those receiving treatment including radiation therapy, surgical treatment such as radical prostatectomy and other therapies etc,. However, characterisation and classification of prostate cancer is very different compared to 40-50 years ago when Gleason scores were first introduced. Despite this radical shift in classification, the Gleason system has remained one of the most important prognostic factors in prostate cancer, only possible as a result of timely and appropriate modifications to this characterisation system made in 2005 and 2014. However, even after these modifications, certain limitations of the Gleason system remain, due to which a new prostate cancer prognostic grade group system was introduced in 2014, which was widely accepted in the 2014 ISUP consensus conference, and incorporated into the WHO classification of thetumor of the Urinary System and Male Genital Tract in 2016. Herein, this article will discuss how this new prognostic grade group system, which is regarded as simpler and more accurate than the Gleason system risk stratification groups, will be used in conjunction with the Gleason system to improve patient prognosis and treatment.