The Gleason grade is used for pathological scoring of the differen- tiation of prostate cancer. This study examined 1207 Physicians’ Health Study and Professionals Follow-up Study participants diagnosed with prostate cancer from 1982 to 2004 and treated with prostatectomy. They compared the distribution of grade and clinical stage across the pre-PSA and PSA screening eras. The authors reviewed grade using the ISUP 2005 revised criteria. The proportion of advanced staged tumors dropped more than six-fold, from the earliest period, 19.9% stage ≥T3, to latest, 3% stage T3, none T4. The proportion of Gleason score ≥8 decreased substantially less from 25.3% to 17.6%. A significant interaction between stage and diagnosis date predicting grade suggests that the relationship between grade and stage varies by time period. As the dramatic shift in stage since the introduction of PSA screening was accompanied by a more modest shift in Gleason grade, these findings suggest that grade may be established early in tumour pathogenesis. The authors conclude that this has implications for the understanding of tumour progression and prognosis and may help patients diagnosed with lower grade disease feel more comfortable choosing active surveillance. Cancer Res. 2013 August. PMID: 23946472
