Implications of the International Society of Urological Pathology Modified Gleason Grading System

Context.-Histologic grading is the clinically most useful tissue-based predictor of prognosis for prostate cancer. Over the years, there has been a gradual shift in how the Gleason grading is applied in practice, with a general trend toward upgrading. A consensus conference was organized in 2005 by the International Society of Urological Pathology (ISUP) for standardizing both the perception of histologic patterns and how the grade information is compiled and reported. Objective.-To review the implications of the ISUP modified Gleason grading system. Data Sources.-Personal experience and review of the current literature. Conclusions.-The recommendations regarding pattern interpretation and reporting are summarized. The practical consequences of the ISUP modification of the Gleason grading are reported. The prognostic importance of the Gleason score, its reproducibility, and its preoperative assessment are discussed. Subsequent proposals for slight modifications to the ISUP grading system are described. (Arch Pathol Lab Med. 2012; 136:426-434; doi: 10.5858/arpa.2011-0495-RA)