PSA Screening: One expert’s personal opinion
“US Preventive Services Task Force (USPSTF) calls for discontinuation of PSA screening for Prostate Cancer”
*listen to Dr. Goldenberg discuss this issue on CBC radio
(discussion begins at 3:00 minutes in)
A U.S. “expert panel” recently concluded that PSA screening does not “save lives” and leads to an unacceptable degree of anxiety and physical complications. This draft recommendation is currently open for discussion and has already raised a firestorm of response from various sectors of healthcare and society, particularly from the urology and oncology experts who actually look after men with all stages of prostate cancer and from prostate cancer survivors.
Men should understand from the outset, that the USPSTF deliberately chooses panelists who are NOT expert in the field that they are reviewing. Generally the panelists are family doctors, statisticians and health administrators who focus on the statistics in the papers, without the ground-level knowledge that comes from treating patients. They see the issues as black and white.
In this case, I believe that the message is a disservice to men and their families. The panel makes a blanket statement which addresses only one outcome (death) of a disease that also causes serious morbidity in its later stages. Before PSA became available 25 years ago, it was common to see men presenting with locally advanced and/or metastatic prostate cancer. I recall that many individuals appeared in my clinic on crutches because of the pain from cancer in their spine and bones. But over the past 20 years PSA has enabled us to detect prostate cancer at much earlier stages and, along with improved treatment modalities, has resulted in a 25% decrease in the mortality of prostate cancer.
PSA is simply a diagnostic test, which has to be interpreted properly and in context. In and of itself, it is an imperfect test and screening men who have no symptoms certainly does lead to a number of unnecessary biopsies and in some cases unnecessary treatment. However, when PSA is ordered and interpreted appropriately it can prevent the devastating effects of metastatic disease and save men’s lives by early detection and early treatment. The five studies which this task force reviewed focus on mortality, and though the differences in survival may not be dramatic overall, there are subgroups, such as men under 65 years of age who do benefit significantly.
My own approach to the use of PSA today is as follows*. Firstly, at the age of 50, men should be advised of the potential benefits and harms of a baseline PSA and DRE (digital rectal exam). There is ample evidence that a very low PSA at this age predicts that a man will unlikely develop significant cancer during the rest of his life, while an elevated PSA at this time should raises concerns and trigger more regular monitoring. Men who have a strong family history should have these baseline tests at age 40 to 45.
Secondly, PSA should not be used in individuals who do not have a life expectancy of at least 10 years because of other serious illnesses (diabetes, heart disease, strokes etc.). It is unlikely that finding and treating early prostate cancer in these individuals will have a positive impact on his longevity and indeed could do “more harm than good”. However, a rectal exam should still be done to check both for a locally advanced and aggressive cancer that might be managed to avoid the problems that could arise before the other illnesses take their toll.
Thirdly, in more elderly men, a digital regular exam needs to be done as part of the general physical examination, with PSA testing only when an abnormality is felt. Quite often a large benign prostate, which occurs with aging, can elevate the PSA and lead to unnecessary biopsies. There are ways of managing these PSA situations and the clinician should be allowed to use “the art of medicine” to do so.
Most important, if a man is found to have a low risk prostate cancer, he and his partner need to be counseled carefully and sensitively about the fact that his cancer is not a ‘biologically relevant’ disease and there is every reason to believe that he can be observed in an active surveillance program. This does not mean that he is being “thrown to the wolves” but rather that he will be monitored carefully and frequently, watching for any signs that his disease is becoming more aggressive or progressive. At that time treatment can be instituted, with very little likelihood that he “missed the boat”.
In summary, the recent recommendations of the US Preventive Services Task Force are throwing “the baby out with the bath water” and may turn back the clock on prostate cancer care by 25 years. Most prostate care providers believe that PSA allows detection of cancer at an early stage and has saved many lives. There is little doubt that many men who don’t need to be screened for prostate cancer are getting screened, and this needs to be controlled. And screening needs to be delinked from treatment: men who have low risk prostate cancer should be counseled that active surveillance or observation is a very reasonable approach to their early stage, slow growing prostate cancer. PSA is not a perfect test, but it is a critically important part of the armamentarium of physicians looking after the male population.
Larry Goldenberg CM, OBC, MD, FRCSC
Professor and Head, UBC Department of Urologic Sciences
Director, Men’s Health Initiative of BC
October 12, 2011
*The BC Cancer Agency recommendations for PSA screening can be found online at http://www.bccancer.bc.ca/HPI/CancerManagementGuidelines/Genitourinary/Prostate/PSAScreening/default.htm