Gleason 6 prostate cancer: serious malignancy or toothless lion?

Autopsy studies of men without known prostate cancer suggest that a substantial reservoir of prostate cancer that does not cause symptoms or death exists within the population. The majority of these cancers are Gleason 6 tumors and are frequently detected by prostate-specific antigen-based prostate cancer screening.There is strong evidence from longitudinal cohort studies of men with both treated and untreated Gleason 6 prostate cancer to suggest that Gleason 6 disease, when not associated with higher-grade cancer, virtually never demonstrates the ability to metastasize and thus represents an indolent entity that does not require treatment. Whether Gleason 6 has a propensity to progress to higher-grade cancer is still under investigation. Because the term "cancer" has historically been used to represent a disease state that leads to progressive illness that is uniformly fatal without treatment, we believe Gleason 6 disease should not be labeled with this term. Our challenge now is to develop the technology to differentiate true Gleason 6 disease from the higher grades of dysplasia with which it can be associated.