Ask Dr. K: PSA test recommended for certain age

DEAR DOCTOR K: I’ve heard so many conflicting opinions about whether or not to get screened for prostate cancer. Are there official guidelines? What do they recommend?

DEAR READER: To say that prostate cancer screening has been controversial is an understatement.

In 2013, the American Urological Association came out with new guidelines that are more or less in line with those of other groups. These guidelines advise against routine screening for men at average risk who are under age 55 or over age 70. For men aged 55 to 69, the guidelines advise that doctor and patient make the decision together, based on a man’s individual risks, preferences and values.

The two ways to screen for prostate cancer are the digital rectal exam and the prostate-specific antigen blood test. Together, PSA testing and DRE may nearly double the detection rate for early-stage prostate cancer.

But there’s a catch. Because other prostate conditions besides cancer can raise the blood levels of PSA, an elevated PSA does not always mean a man has cancer. We call a high blood level of PSA in a man without prostate cancer a “false positive” result.

False positive results can cause needless worry. And they may lead to invasive procedures, such as biopsies, to determine if cancer is present.

The bigger problem, however, is this: As strange as this may sound, not all cancers are bad for your health. Some prostate cancers are so small and slow-growing that they will never spread and cause problems: You’ll die of something else. You’ll die with prostate cancer, but not from prostate cancer.

Unfortunately, the PSA test cannot distinguish well between aggressive and slow-growing tumors.

A final weakness of the PSA test is that it does not detect all cancers. In other words, just as the test can be falsely positive, it can also be falsely negative: It comes back normal (“negative”), but you really do have prostate cancer. In such cases, a PSA test offers a false sense of security.