Does the reflexive measurement of free PSA have a role in a tertiary cancer centre?

The percent free prostate-specific antigen (PSA) may complement total PSA for prostate cancer screening, but is of no benefit for monitoring patients with previous prostate cancer diagnoses. At the Princess Margaret Hospital, a tertiary cancer centre in Toronto, Ontario, Canada, PSA values in the range 4 to 10 ng/mL prompt reflexive measurements of free PSA. We hypothesize that reflexive free PSA testing at tertiary cancer centres generates unnecessary costs as the test is often conducted on patients with previous diagnoses of prostate cancer.

We reviewed all reflexive free PSA measurements conducted on a random sample of 250 men in a 10-year period at our institution. We determined the clinical indications for the PSA tests which triggered reflexive free PSA measurements to estimate the proportion of free PSA tests that are not clinically indicated.

We reviewed the 1099 reflexive free PSA measurements for the 250 subjects. Of these tests, 562 (51%) were triggered by PSA tests ordered for screening/early detection, and 537 (49%) for monitoring.

Of all reflexive free PSA tests, 49% were unnecessary. We conducted 3022 free PSA tests, at a cost of $5.84 per test (Can$); the tests were performed in 2009 at this institution for a total cost of $17 648.48, about 49% of which ($8647.76) likely represents unnecessary annual costs. We suggest a trial of user-selectable order sets allowing physicians to choose whether to include reflexive free PSA measurements on a case-by-case basis. This policy might improve the cost-effectiveness of the PSA test at tertiary cancer centres.