In the past, the total PSA value over 4.0 was considered suggestive of prostate cancer. Subsequent experience has shown this to be inadequate as an absolute cut-off.
Among the ways we have changed our analysis of the PSA is looking at PSA velocity (change of PSA over time) with a rise in PSA over 0.5 per year as suggestive of cancer.
In this recent paper in the Journal of the National Cancer Institute the usefulness of the PSA velocity has been called into question. The PSA velocity, is itself inadequate and can be misleading.
With this information it is difficult to know the exact usefulness of this test, but still I think it is reasonable to use this test on interval basis (typically at a yearly physical), and then to put this number into perspective, with retesting, comparison with prostate exam, and cautious observation.
PSA’s are imperfect, but used as a general guide, and not an absolute arbiter, I will continue to use this test, as it has proven useful in too many instances in patients that I’ve cared for.