The Doctor Is In: PSA or no PSA?
Guest post by Phillip K. Peterson, M.D.
All adults—even doctors when they become patients—are faced with decisions about diagnostic tests and treatments. One of the biggest controversies in recent years in the arena of diagnostic testing has been the value of the blood test for prostate specific antigen (PSA) as a screening tool for prostate cancer. At the time that I agreed to having my PSA checked in October 2010, I had no symptoms of prostate cancer and the evidence in support of the test was beginning to wane. But my primary care internist was a believer. So, after a vigorous discussion, I reluctantly agreed. Because my PSA was elevated, I subsequently had three prostate biopsies, which showed early and a somewhat progressive cancer. Now, almost a year after a radical prostatectomy with lingering symptoms related to the surgery, how do I feel about my decision regarding the PSA test?
The answer to this question can be found in my book Get Inside Your Doctor’s Head: 10 Commonsense Rules for Making Better Decisions about Medical Care. The two underlying premises of the book are that it is useful for patients to understand something about how doctors think (thus the title) and that commonsense should guide all medical decisions (the basis of the 10 Rules of Internal Medicine). In my case, in October 2010 I was concerned about breaking Rule 5: If you don’t have symptoms, a doctor can’t make you feel better. At the time, however, the prevailing opinion was that the PSA is of value in screening for prostate cancer, so I agreed to having the test even though I worried about Rule 6: Never trust anyone completely, especially purveyors of conventional wisdom.
Sure enough, in 2011 and 2012 evidence from large well-carried out clinical trials, made it clear that the PSA is of no value as a screening test for prostate cancer. And importantly, radical prostatectomy doesn’t improve survival of patients with early stage cancer like mine. Such a surprising finding, isn’t all that uncommon in medicine. Think of the conventional wisdom years ago about the benefit of treatment of post-menopausal women with hormones. There too, well-done clinical trials showed more risks than benefits.
Thus, knowing what I know now, I recommend against PSA testing. Sadly, for a cancer that kills about 30,000 men per year in the United States, a reliable screening test does not yet exist.
Phillip K. Peterson, M.D., is a professor of medicine and an infectious diseases specialist at the University of Minnesota Medical School. The 10 Rules of Internal Medicine were developed during his more than three decades of caring for patients and teaching medical students and residents at the University of Minnesota Medical Center and Hennepin County Medical Center, both in Minneapolis. Written for non-medical readers in the current era of “Patient-Centered Care,” his book helps empower patients—to get in the driver’s seat, to take command of the medical decisions they make for themselves or their loved ones.