By Urologist, Michael T. Macfarlane, M.D.
Screening for prostate cancer has again made the news largely because the new chief medical officer of the American Cancer Society, Dr. Otis Brawly interprets the data as not showing enough benefit for screening.
A few personal observations and opinions on the subject:
- The kinds of studies that are used to come to these types of clinical conclusions are not strict science like you learned about in high school chemistry where all of the variables are well controlled i.e. atmospheric pressure, temperature, chemicals in the test tubes, etc., etc. Most of these studies are retrospective chart reviews with innumerable uncontrolled variables. Statistical methodology helps to smooth out some of the discrepancies but falls far short. We continually see clinical conclusions overturned in subsequent studies, a clear indication of clinical medicines shortcomings.
- Prior to the clinical appearance of PSA screening in the late 1980’s, prostate cancer was only detected by a digital rectal examination, perhaps the most inaccurate diagnostic test known to medicine. Fifty percent of men had metastatic disease at the time of first diagnosis prior to the PSA era. That is clearly unacceptable and that is exactly where we will be if Dr. Brawly turns the clock back a quarter of a century in prostate cancer progress.
- Dr. Brawly and most of the epidemiology crowd are making a major error because they are focusing on the wrong question. The data on prostate cancer outcomes suggests that perhaps we may be over treating some patients with a non-aggressive form of the disease, not that we are over diagnosing the disease. Because non-aggressive prostate cancer may present minimal threat to some individuals does not mean that we should stick our heads in the sand and wait for patients to become symptomatic. It is too late to help a man who has symptomatic prostate cancer; he will invariably succumb to the disease. PSA screening has been the best tool we have to prevent this horrible outcome.
- Much of the controversy is being stoked by Affordable Care; yes politics, just as we saw a year or so ago with the controversy over mammography. The U.S. Preventive Services Task Force is an unelected group of people who are making decisions for every American about what care they can and cannot access. They are focused more on costs than benefits. A PSA test costs less than $10. An abnormal PSA has a positive predictive value of 25% or better with higher PSA levels. When one takes into accounts all of the costs of diagnosis, including biopsies, PSA is far more cost effective than mammography or colonoscopy.
Image from: www.myhealthnewsdaily.com
Michael Macfarlane, M.D., graduated AOA from the College of Physicians & Surgeons, Columbia University in New York. He trained in general surgery at the Harvard Medical School and urology at UCLA. In addition to numerous scientific articles, he has authored a popular text for medical students, residents and primary care doctors entitled “Urology” (House Officer Series) now in it’s fourth edition 2006 and has been translated into four foreign languages (the fifth edition due in 2012). Presently, he is in practice with Urology Care, LLC and a Clinical Associate Professor of Urology at the University of Louisville School of Medicine. Dr. Macfarlane specializes in urologic oncology and diseases of the prostate. For more information, go to www.urologycare.org.