August 17, 1996
Letters to the Editor Scientific American 415 Madison Avenue New York, N.Y 10017-1111
The excellent article by Hanks and Scardino omits any mention of the reproducibility and false interpretations of PSA scores. It is known that prostatitis causes increases, but there is no information on how recent unrelated illnesses can cause dramatic rises. Recently I took a PSA test when I visited the hospital because of such an illness. The score jumped from my normal level of 5 to 43! I chose a repeat test rather than a biopsy. In a week it had dropped to 22, still a huge score. Being a physicist I theorized that the score would fall exponentially with time. Repeated measurements showed this precise behaviour and after 4 weeks the score returned to normal where it has remained. Searching hospital records could determine whether certain illnesses cause PSA fluctuations for which I only give anecdotal evidence. But urologists do not know whether such correlations exist and lay persons are apt to become frightened and choose invasive biopsies prematurely.
Sherman Frankel, Emeritus Prof. of Physics, University of
Pennsylvania