In view of the recent hooraw over whether or not testing for and treating prostate cancer saves lives, I feel I should re-visit this subject, which I first discussed in my blog of May 15, 2009. I want to begin by emphasizing once again, speaking as a trained scientist, that in any given field what counts is what we can show to be true by experiment, and not what we can deduce or think should be true (with Einstein's Theory of General Relativity being a notable exception, but even that theory was based upon an experimental result, namely the equivalence of inertial and gravitational mess, as first shown by Galileo). It also doesn't matter what we would like to be true, because Mother Nature's rules are independent of our beliefs.
Some of the examples of medical facts and treatments that we thought should be true or benefit patients but were shown to be false or harmful or not proven when subjected to clinical testing are:
1) If a patient has calcium oxalate kidney stones then the proper treatment is toDEcrease the amount of calcium in the diet.
2) Beta-blockers should never be used in a patient who is in heart failure.
3) Everyone needs 8 glasses of water or fluid a day for good health.
4) Everyone needs at least one bowel movement a day.
5) If a patient is ill, bleeding with leeches will generally make him/her better.
6) An hour of sleep before midnight is worth two hours after.
7) If you go swimming right after eating you will develop an abdominal cramp and drown.
8) Vitamin E, because of its anti-oxidant properties, prevents heart attacks.
9) Beta-carotene, because of its anti-oxidant properties, protects smokers from lung cancer.
10) Mammograms taken between the ages of 40 and 50 saves lives.
11) The optimum time interval between complete physical exams is one year.
12) The optimum time interval between colonoscopies is 10 years.
13) The optimum time interval between mammograms is one year.
14) A drink of alcohol a day cannot possibly be good for you.
15) Daily doses of saw palmetto help treat an enlarged prostsate.
16) Daily doses of gingko balboa help prevent Alzheimer's Disease.
I could easily add another 10 to 20 pseudofacts to the above list. Now let us look at the question of PSA testing as well as the treatment of prostate cancer. Before asking whether or not measuring the PSA saves lives, we first have to determine if treating prostate cancer saves lives. As of today, there is absolutely no evidence that it does. It may seem counterintuitive that this is so, but the fact is that the majority of men die WITH prostate cancer, and not OF prostate cancer. Roughly speaking, the percentage of men who have prostate cancer at autopsy is equal to their age at death: 70% of men at age 70 have microfoci of prostate cancer, etc. Much as we would like to believe that detecting prostate cancer early and treating it will save lives, there is absolutely no evidence that this is so.
There have been many review articles coming to this conclusion, and you can check PubMed, the abstract archive of the National Institutes of Health for references. So why do people do the PSA, or take treatment if a prostate biopsy shows prostate cancer? The answers are many and varied, and all are ultimately the result of individual decisions by individual patients. Some of the reasons are:
1) Some people cannot tolerate the thought of having cancer within their bodies.
2) Some wives cannot tolerate the thought that their husband is walking around with cancer.
3) Some men believe that treatment of prostate cancer will save their lives.
Very few men are told that most prostate cancers detected on biopsy will not spread and kill them. Very few men are told of the possible lingering (6 months to 2 years) or permanent symptoms of radiation proctitis that can result (chronic bloody or non-bloody diarrhea). Many men don't fully understand the implications of the fact that 30% of treated men will develop urinary incontinence (and need to wear a diaper) or be unable to mount or maintain and erection (even with the help of Viagra), or both.
Since a physician's first duty to his/her patient is to "do no harm", I lay out all the above info to my patients, and if asked, I tell them that I never have taken a PSA test and would never treat prostate cancer in myself. However, if a patient decides on treatment, I urge him to consult with both a urologic surgeon and a radiation oncologist to listen to the pros and cons of each procedure, and then to consult with a medical oncologist for an overall view. I also suggest that he not discuss his decision with any friends who have been treated in order to avoid impassioned but not dispassionate arguments and lectures. And then I remind him that it is his body, that he is the patient and must make the final decision, and not to do any treatment or non-treatment that he does not fully agree with.