Should Gleason 6 Still Be Considered Cancer? A Narrative Review of its Biology and Clinical Course, with Implications for Guideline Recommendations and Practice Implementation.

Gleason 6 prostate cancer, also classified as grade group 1 (GG1), demonstrates exceptionally indolent behavior with minimal risk of metastasis or mortality. Despite this, its designation as cancer drives overdiagnosis, overtreatment, and patient anxiety. This review examines the historical evolution of the Gleason grading system, pathologic and molecular characteristics of GG1 disease, and long-term outcomes from landmark trials and contemporary cohorts. We explore the implications of current diagnostic and management strategies and finally propose guideline reforms and implementation strategies aimed at reducing overtreatment, improving communication, and supporting observation and PSA-based monitoring as preferred options for most men with GG1 disease.