A key point that evidence-based medicine proponents stress is the need to focus on patient outcomes, rather than on issues such as lowering the level of a chemical in your blood. They call treatments focused solely on a physiological result (such as lowering homocysteine levels without a concomitant patient benefit) a “disease-oriented outcome” or “disease-oriented evidence” and contrast it with “patient-oriented evidence that matters” or POEMs.

Prostate specific antigen (PSA) is an example of another “disease-associated” chemical, and the PSA test is a case in point of how the media and consumers can get ahead of the science.

For example, advice columnist “Dear Abby” recently published a letter advising male readers to get a PSA test to screen for prostate cancer as often as women get mammograms, which means every year after age 40. Abby’s recommendation is not consistent with the recommendations of leading healthcare organizations (see Screening Tests for Adults: Prostate Cancer), but shows how tempting it is to jump at a test that we hear can “spot” cancer early.

The test’s allure has been powerful even in the medical community, but it remains so controversial that the recommendations for its use are still in flux, with many experts unconvinced about its usefulness. The Food and Drug Administration approved the PSA test as a cancer screen in 1994, and a decade might seem like enough time to draw some conclusions. But prostate cancer is very slow-growing—one study followed 3,000 men for seven years—so it will take a very long time to compile convincing evidence. (For more on the questions that PSA tests can raise, see Experts Disagree on Use of PSA Test.)