Should we be letting the sleeping dogs lie?


On November 12 we posted an introductory reference to a new publication, called Let Sleeping Dogs Lie, that lays out the argument against mass, population-based screening of every man over 40 (or 50, pick a number) on the grounds that it is unjustifiable, fosters fear, and leads to the over-treatment of tens of thousands of men every year, just because they have a few cancer cells in their prostate.

We have now had a chance to read this entire book. It is available through the University of Sydney’s eScholarship Repository, and it is available free as a PDF file.

The first thing that we should say is that people should read this book. It presents a well-constructed point of view. It endorses, with sound arguments, the rationale for the non-use of mass, population-based screening. It debunks some sacred cows — most particularly the idea that early, invasive treatment is now “saving the lives” of tens of thousands of (young) men being diagnosed with prostate cancer every year. And it most certainly justifies the belief that, for those who don’t want to be tested, there are sound reasons for not getting regular PSA tests (so long as you are willing to accept the consequent risks).

Unfortunately what the book does not do well is provide a balanced viewpoint through which the pros of screening can be balanced against the cons. Just as the pro-screening lobby stresses the idea that “every man over age [insert a number] should get an annual PSA test,” this book stresses the idea that “screening for prostate cancer isn’t justified.” It also puts forward an argument that those who substitute the word “testing” for “screening” are guilty of just promoting mass screening without using the term correctly.

The problem, of course, is that we really do need to be able to identify, as early as possible in the course of their disease, the 30,000 or so men (in America) who will otherwise go on to die of prostate cancer each year. We also need to be able to identify early the less well-defined number of men who will have progressive disease that becomes metastatic or has other clinical symptoms that would benefit from early treatment. In America that is probably about another 40,000 men each year. And at the moment we have no good way to identify these 70,000 men and discriminate between them and the other 130,000 men currently diagnosed each year who are likely to not die of prostate cancer and not ever show clinically significant symptoms of prostate cancer that would make treatment essential. These are the men who are at risk for over-treatment (and arguably for over-diagnosis, depending on how one wishes to define that term).

The “New” Prostate Cancer InfoLink, in September this year, outlined one possible method to move forward that might help to limit unnecessary PSA testing and unnecessary biopsies in men at minimal risk for clinically significant prostate cancer. This proposal (or something like it) needs to get tested. It is based on the concept of risk-based testing as opposed to mass, population-based screening. And it does not exclude appreciation of the fact that the unjustified fear of prostate cancer is now a major driver of testing for many men.

At the end of the day, the PSA test is what we have now to help us identify men at greater risk than the average from a current or a future diagnosis of prostate cancer. It won’t help us find every patient with high-risk disease early enough. And it most certainly doesn’t help us to not treat men who don’t really need treatment. We need a better test. We need to be able to aggressively support the use of active surveillance instead of immediate invasive therapy in as many men as possible. And if we had a better test, we might be able to differentiate with much greater accuracy between those who really need treatment and those who don’t, which might spare many of the latter from the rigors of active surveillance (let alone over-treatment).

We need a common ground — shared by pathologists, epidemiologists, urologists, primary care physicians, and others, that says we really don’t know how to diagnose and manage clinically significant prostate cancer well (yet) at all — and that that is a particular problem because of the recent ability to identify very early stage, low-risk, potentially indolent forms of the disease. Given that common ground, the decision to diagnose and treat an individual patient requires cautious and careful assessment in each and every case — an assessment that helps everyone get beyond excessive fear, but which is acceptant of the reality that prostate cancer is a severe and chronic condition that does kill young men in their 40s (albeit not often) as well as old men in their 70s, 80s and 90s (with a great deal more regularity).

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