Repeat PSA Tests to Avoid Unnecessary Biopsies

Gerald Chodak, MD


February 18, 2016

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Hello. I'm Dr Gerald Chodak for Medscape. Today I want to talk about ways we can try to reduce the number of biopsies being performed on men who have an elevated prostate-specific antigen (PSA), in order to thereby decrease the number of cancers being detected that may not be life-threatening.

Lavallée and coworkers[1] performed a prospective evaluation of about 1300 men in Canada. Their aim was to see if PSA levels between 4 and 10 ng/mL were noted again in follow-up testing before men underwent a prostate biopsy. They found that when they repeated the test, about 25% of the men dropped below the 4 ng/mL threshold. Of that group, 89 still underwent a prostate biopsy, with cancer detected in 8.3% (26 of 311 men). That compared with a much higher 35% rate (336 out of 953 men) of cancer detection if the repeat PSA remained between 4 and 10 ng/mL.

By doing a repeat PSA, the authors gave a lot of men an opportunity to avoid undergoing a biopsy. Granted, this was not a perfect solution, because a small amount of men who experienced a drop in PSA still had cancer, although the authors found that only about 3% of them had a Gleason score of 7 or higher.

There is always going to be a tradeoff whereby we perform too many biopsies and find cancers that are not life-threatening, or we apply a system in which we miss out on some cancers that could be detectable. What could happen over time, however, is that men not lost to follow-up are given another PSA exam sometime in the future. If it goes back up again, many men who might have been missed with their second PSA test are still likely to be diagnosed at a later point.

The authors also performed a sensitivity analysis in which they used a 2.5-ng/mL instead of a 4-ng/mL cutoff. When they did, 11% of the men dropped below 2.5. Therefore, doctors who want to be a little bit more conservative could use a lower threshold. Another sensitivity analysis the authors performed was to look at age-specific PSA cutoffs, after which they observed an even higher rate of men falling into the normal range. Such efforts represent an opportunity to change the detection rate, now that the pendulum has shifted to trying to avoid overdiagnosis of prostate cancer and giving too many men a biopsy they don't really need.

The American Urological Association (AUA) has recommended that physicians not decide on a biopsy with a single PSA result. Instead, they're encouraging the use of repeat PSA testing, particularly in men who have never had a biopsy before or don't have a family history of prostate cancer. Yet, when we look at the results from primary care physicians, it is clear that they are often not following that recommendation. Perhaps they're being conservative by sending the patient to a referral center for further evaluation, but they should be encouraged to look at this approach rather than making a decision based on a single PSA test.

Of course, there are cost implications to subjecting every man with an abnormal or elevated PSA to another test. For the most part, though, this effort should still result in an overall cost savings because fewer men are undergoing a prostate biopsy.

There are additional studies in the literature supporting these changes in practice, as well as those reporting that PSA fluctuations can occur. For now, it would seem that a prudent approach would be one where we can lower the detection rate of men who may not have life-threatening cancer, subject fewer men to a prostate biopsy, and in the end still avoid a high incidence of cancers that progress to being incurable.

I look forward to your comments. Thank you.


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