We read with great interest the article entitled "Effect of Digital Rectal Examination [DRE] on Serum Prostate-Specific Antigen [PSA] in a Primary Care Setting,"1 published by the Internal Medicine Clinic Research Consortium. We take exception with the authors'1 conclusion that the DRE causes a clinically insignificant increase in the serum PSA level.
The Internal Medicine Clinic Research Consortium found that the PSA level increased in 72% of patients, while the expected figure would be 50% if the DRE had no effect. The average increase was about 10% (0.26 μg/L) of the mean level found before DRE. While it is true that a change from 2.0 to 2.3 μg/L is probably of no clinical consequence, the authors showed that the observed increase after DRE tended to be greater for larger basal PSA levels. More impact is therefore expected with patients with borderline values between 3 and 4 μg/L.