Changes in Prostate Cancer Grading: Including a New Patient-centric Grading System

The first structured approach to grade prostate cancer based on the underlying histological architecture was developed by Donald Gleason who in 1966 proposed a morphologic classification of prostate cancer and in 1974 demonstrated its clinical significance based on prostate cancer-specific death. Contemporarily referred to as the Gleason grading system, it has gained worldwide recognition allowing a more individualized approach to patients with prostate cancer. In 2005, the International Society of Urologic Pathology (ISUP) made the first revisions to the grading system. Subsequently, based on the new discoveries in pathologic and clinical aspects of prostate cancer, as well as the changing nature of the prostate cancer in part due to a robust screening, there was a need for experts to re-visit the approach to grade prostate cancer. In November 2014, the ISUP experts and clinical leaders in prostate cancer from 17 countries conducted a consensus conference in Chicago, IL, USA. The consensus conference defined various grade patterns and proposed the adoption of a new grading system of prostate cancer. Herein, we describe the background and rationale for the changes and provide guidelines to their clinical implementation.