How did the PSA system arise?

Abstract

A few years ago, a notable paper criticized prostate-cancer screening as a defective system lacking negative feedback. A PSA test yields either an unsuspicious or a suspicious result. If the former, the patient is relieved; if the latter, he is biopsied and cancer is either confirmed, in which case he is dismayed but presumably relieved that it was discovered early, or not confirmed, in which case he is again relieved. PSA testing seems to generate no outcome that does not reinforce the testing regime itself, even though it is well-known, at least to medicine, that it leads to over-detection on a large scale, that diagnosis leads to treatment, and that treatment entails the possibility of such side-effects as impotence. As for the benefits of PSA testing other than feelings of relief regardless of the outcome, they are difficult to establish. ‘There seems to be a “disconnection” between the degree of enthusiasm for screening and the quality of the evidence supporting it’. At the time the PSA regime took shape in the USA in the late 1980s and early 1990s, significant mortality benefits were expected but had not yet been confirmed; with two randomized clinical trials of PSA reported in 2009, one showing no mortality benefit and the other a modest benefit at the cost of much overtreatment, the hoped-for dividends of PSA testing have still not materialized. For two decades, therefore, men by the thousand have been diagnosed with and treated for prostate cancer in the belief that PSA saves lives, despite a paucity of evidence that it actually does so. In the early years of the PSA era, some concluded that the use of a screening test as flawed as PSA could only be explained by the undue influence of the healthcare industry on the making of cancer policy. The flaws of PSA testing – in particular, its speculative benefits but probable harms – were sharply criticized in the medical literature itself. Yet the test very soon acquired a popularity that enabled it to shrug off the skepticism of critics and the caveats of the US Preventive Services Task Force, which in 1996 declined to recommend either in favour of or against PSA testing owing to the uncertainty of the evidence. How is it that a test of such disputed value was so warmly embraced by American men? The answer lies not only in the endorsement of PSA testing by such bodies as the American Cancer Society and the American Urological Association, but especially in the use of public-relations methods to drive home the powerful but too-simple message that PSA saves lives – methods that had already proven themselves in the case of the sister disease, breast cancer. The PSA system as we know it could conceivably have been built from the ground up by urologists convinced that they did not have time to wait for the results of RCTs of PSA, given that deaths from prostate cancer stood at 40,000 per year in the USA when screening for the disease began. However, urologists did not invent every element of the system. Key components, including the rhetoric of early detection that drives men to get tested in the first place and vindicates the test no matter the result, were imported from breast-cancer medicine. Historically speaking, mammography has led and PSA testing has followed even though PSA lacks to this day the sort of validating evidence that mammography possessed before the PSA revolution began. One answer to the question ‘Why Is DECLARATIONS