Description of a novel grading system for prostate cancer

Unmet Need
The current prostate cancer grading system was developed between 1966 and 1974 by Donald Gleason and the Veterans Administration Cooperative Urologic Research Group. The system assigns histological patterns 1 through 5 with a Gleason score derived from adding the most and 2nd most common patterns. Scores range from 2 (well-differentiated) to 10 (undifferentiated). Over the subsequent 40 years, histological and clinical diagnosis of prostate cancer along with its treatment has evolved, leading to revisions of the Gleason system first codified in 2005 and more recently in 2014. The current application of Gleason grading differs dramatically from the original system.  Scores 2-5 are currently no longer assigned and certain patterns that Gleason defined as a score of 6 are now graded as 7, thus leading to contemporary Gleason score 6 cancers having a better prognosis than historic score 6 cancers.
 
There are significant deficiencies with the current application of the Gleason system that have impacted patient care.  A Gleason score 7 can represent mostly well-differentiated cancer with a lesser component of more poorly-differentiated cancer (Gleason 3+4=7) or mostly poorly-differentiated cancer with a smaller component of well-differentiated cancer (4+3=7).  Treatment decisions using a simplified single Gleason score of 7 fail to recognize that 3+4=7 and 4+3=7 are prognostically very different.  Another critical weakness of the Gleason system is that in practice the lowest score is now assigned a 6, although it is on a scale of 2-10.  This leads to a logical yet incorrect assumption on the part of patients that the cancer is in the middle of the scale, compounding the fear of a cancer diagnosis with the belief that the cancer is serious, thus leading to an expectation that treatment is necessary. There is a need for a new grading system that addresses the flaws of the Gleason system.
 
Technology Overview
Johns Hopkins researchers developed a new, 5-tier grading system that addresses the confusion inherent in the Gleason system, and is defined as follows:
  Gleason score ≤ 6:Prognostic Grade Group IGleason score 3 + 4 = 7:Prognostic Grade Group IIGleason score 4 + 3 = 7:Prognostic Grade Group IIIGleason score 8:Prognostic Grade Group IVGleason score 9–10:Prognostic Grade Group V  
Researchers verified that this new grading system accurately differentiates between the most significant prognostic differences using multi-institutional and multi-modal therapy data.
 
Stage of Development
Complete
 
Publications
Epstein, J.I., A Contemporary Prostate Cancer Grading System: A Validated Alternative to the Gleason Score. 2015 Jul 10.
 

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