PSA screening for prostate cancer: why so much controversy?

Abstract

Since prostate cancer reaches the advanced and non curable stage in the absence of any specific symptom or sign, it seems reasonable to diagnose this cancer at an early and curable stage. Screening by prostate-specific antigen (PSA) has been the common technology used. The last follow-up of the first two prospective and randomized screening studies for prostate cancer, namely the Quebec and ERSPC (European Randomized Study of Screening for Prostate Cancer) clinical trials started in 1988 and 1991, respectively, have shown reductions of prostate cancer death of 62% (P<0.002) and 21% (P<0.001) (38% in the tenth and eleventh years of follow-up, P<0.003), respectively, while the PLCO (Prostate Lung Colorectal and Ovarian Cancer) screening trial reported no benefit. It has been estimated, however, that 85% of men in the planned 'non-screened' group of the US study have been screened. With such a serious flaw, the PLCO study does not have the statistical power to reach any valid conclusion. In the Quebec study, only 7.3% of men were screened in the control arm. The important benefit observed in the ERSPC study was achieved using a less than optimal 4-year PSA screening interval which misses a significant number of cancers while the Quebec study used the optimal 1-year interval. With proper information obtained from their physicians or otherwise using data collected only from the clinical trials having the required statistical power, men should be in a good position to decide about being or not being screened for prostate cancer.