Margaret A.WinkerMD, Senior EditorIndividualAuthorPhil B.FontanarosaMD, Senior EditorIndividualAuthor
To the Editor.—Dr McNaughton Collins
and colleagues1 report that more than 25%
of cancers detected through DRE and PSA testing are detected by serendipity.
Their model for serendipity with PSA testing is based on a single autopsy
study that reported that cancers smaller than 1 cm3 seldom raise
serum PSA levels above 4 ng/mL.
Previous studies have demonstrated that PSA levels do not reliably reflect
tumor volume.2 The extent to which a given
volume of prostate cancer will increase the serum PSA level of an individual
patient depends not only on the tumor volume, but also on other factors, such
as the degree of histologic differentiation of the tumor, the hormonal status
of the patient, and the patient's total blood volume. The men in the autopsy
study described by McNaughton Collins et al were near death when their blood
was drawn for PSA testing. Their nutritional status and pituitary-gonadal
axis (which can affect serum PSA levels) were far different from those of
healthy men who present for prostate cancer screening.
Catalona WJ, Smith DS. Detection of Early Prostate Cancer: Serendipitous or Systematic?. JAMA. 1998;279(18):1439-1441. doi:10-1001/pubs.JAMA-ISSN-0098-7484-279-18-jac80006