And to add to the confusion about annual prostate cancer screening …

… a paper from the University of Texas Health Sciences Center in San Antonio has provided a detailed analysis of the spectrum of variation of PSA and DRE data among men in an earlier screening program.

Ankerst et al. identified a total of 2,578 participants in a San Antonio screening cohort who had two or more consecutive, annual PSA and DRE tests. They then compared the ocurrences of an increased PSA level — to a value of ≥ 2.5 ng/ml — followed by one or more non-increased PSA results with similar changes in the DRE result from abnormal to normal.

Prostate biopsy is often recommended based on increases in prostate specific antigen and/or abnormal digital rectal examination. We investigated the stability of a single positive test during the next 3 consecutive years.

The resulta of this analysis can be summarized as follows:

  • 2,272/2,578 participants (88.1 percent) who met the study entry criteria did not have a biopsy during the study.
  • In 173/744 participants (23.3 percent) who did have an increased PSA level at 1 year of follow-up, the next PSA value was not increased.
  • In 90/462 participants (19.5 percent) who did have an increased PSA level at 2 years of follow-up, the next two consecutive PSA levels were not increased.
  • In 50/285 participants (17.5 percent) who did have an increased PSA level at 3 years of follow-up, the next three consecutive PSA levels were not increased.
  • Rates were similar but lower in 221 men who had one or more negative biopsies during the study and in 85 men in whom prostate cancer eventually developed during the study.
  • Approximately 70 percent of participants who had abnormal DREs had normal DREs the following year — even in patients with prostate cancer, and in the majority of incidences their DREs remained normal for the next 2 to 3 consecutive years.

The authors conclude that reversal of data suggesting the need for prostate biopsy one or more years after the initial PSA and DRE data are collected is not uncommon. They go on to suggest repetition of these tests in such patients. However, The “New” Prostate Cancer InfoLink is tempted to suggest that  there is a whole other way to interpret these data, and that is to consider the possibility that we have been ober-eager to biopsy men on the basis of a single set of relatively inconclusive PSA and DRE test data, and that what this study really does is confirm, yet again, just how poor the PSA and the DRE tests are at suggesting the risk for clinically significant disease.

3 Responses

  1. I read that paper about five times this morning and I’m still confused of it’s worth!

    I can understand this article published in the UK this morning though:

    Cancer patient urges men over 50 to take regular tests.

  2. I do not find it surprising that biopsies are ordered on the basis of a single unreliable test, whether positive DREs or PSAs, in light of the fees charged for performing a biopsy and the malpractice risk associated with not ordering a biopsy test.

  3. I read the paper six times and agree with Mike’s conclusions.

    It seems like this throws all the conclusions about PSA — levels, velocity, density, doubling time and free PSA — into a cocked hat. You’ve got to wonder if the majority of “PSA rising” is about prostatitis.

    I don’t think this will make any of those on active surveillance sleep any easier — conundrums within conundrums.

    I’m liking my 3-D mapping biopsy better and better.

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