Ask the doctor: Concern about a now "normal" PSA

Ask the doctor

Q: I am 68 years old, and recently my PSA level (which was normal before) increased to 5.2 nanograms per milliliter (ng/ml). My doctor repeated the test one month later, and it was normal again at 3.3 ng/ml. Should I still be concerned?

A: One of the reasons that routine PSA testing is so controversial is the inability of the test to distinguish men with prostate cancer from those without it. A common cutoff is 4 ng/ml, but this is hardly a black-and-white answer. In fact, 30% of men with a PSA result between 4 and 10 have cancer. (The remaining 70% have benign causes, like an enlarged prostate.) In men with a "normal" PSA in the 2-to-4 range, 20% have cancer. So the risk is still present.

Guidelines recommend that an abnormal PSA level (4 ng/ml and higher) be checked again before any invasive testing begins. This is because many conditions increase the PSA reading. In a recent study published in Mayo Clinic Proceedings, about 25% of men with an abnormal result had a normal one when the test was repeated.

If your PSA level increases transiently—that is, it goes up briefly and then returns to normal—it does not appear that you are at any elevated risk of prostate cancer. Yet the risk is still present with a normal PSA reading. It is uncertain when the next test should be, but it is often repeated in six to 12 months.

The lack of accuracy of the PSA test combined with the uncertainty of treatment effectiveness for early prostate cancer has led to some medical groups recommending against its routine use for cancer screening. If you choose to be screened, you should be aware of the potential for false alarms or false reassurance. If it is elevated, ask your doctor to look for other causes, such as infection, and to repeat the test after four to eight weeks.

— William Kormos, M.D.
Editor in Chief, Harvard Men's Health Watch