Prostate-specific antigen screening for prostate cancer: no reduction in Gleason scores.

Skepticism regarding prostate-specific antigen (PSA) screening arises from the possibility that screening procedures increase the yield of diagnosed prostate cancers occurring in an indolent form that does not require treatment. If PSA screening serves only to increase the yield of clinically trivial prostate cancer, one would expect a drop in the average Gleason score of prostate cancers detected with PSA screening compared with prostate cancers detected before the advent of PSA screening. In a 3-yr study of newly diagnosed prostate cancer, there was almost a 7-fold increase in PSA screening tests ordered between 1989 and 1992 and a greater than 2-fold increase in the number of newly diagnosed prostate cancers. In the same time period, the average Gleason scores of newly diagnosed prostate cancer increased slightly (from 6.2 to 6.5). In this study there was no prognostic difference (as predicted by Gleason score) between prostate cancers in populations whose cancers were diagnosed before and after the increased use of PSA as a screening tool.