I enrolled for the Preventing Overdiagnosis conference assuming that the focus would be on cancer screening, but I was thankful that the conference covered every clinical specialty, including paediatrics, psychiatry, and cardiology, as well as surgical specialties and emergency medicine. After all, and as recounted by Jim Guest, it is possible for patients attending the Emergency Room for a fall related minor injury to be “treated” with an array of tests (including a brain scan) to make sure that the fall wasn’t caused by a heart attack or a stroke.
Co-host Ray Moynihan (Bond University) together with Lisa Schwartz and Steven Woloshin (Dartmouth Institute) described different mechanisms that may result in overdiagnosis.  One of those is the use of new and more sensitive tests that improve diagnostic accuracy, but also detect biological processes that often have no apparent health consequences, a case exemplified by CT-detected sub-segmental pulmonary embolism.
Other mechanisms leading to potential overdiagnosis include the expansion of disease definitions (as argued for diabetes, hypertension, and chronic kidney disease); or the branding of obscure disease entities of uncertain existence, nature, and prognosis, such as restless leg syndrome.
As ever, some of the best contributions came from the US, although (or perhaps because) the US healthcare system appears to be the most challenged. The US Preventive Services Task Force exemplifies how independent guidelines committees can deal with limited and uncertain evidence. Its current chair, Virginia Moyer, is a down-to-earth, say-it-as-it-is, clinical leader who can be credited for turning a previously unknown institution into a global cause célèbre for rational policymaking during her watch.
The number of attending US patients and consumers was impressive. It was good to see patient advocate organisations independently scrutinising the efficacy claims of, for example, new dementia drugs, as done by Consumer Reports. Opportunity costs associated with overdiagnosis and overtreatment (whilst many patients continue to be under-diagnosed and under-treated) were often highlighted.
What is the way forward for dealing with overdiagnosis in the future? Progress is needed along three key dimensions: study methodology, diagnostic technology, and patient communication.
We should try to enhance our scientific understanding about how overdiagnosis can be defined, measured, and reported. It is after all a highly complex concept, as summarised by Norwegian epistemologist Bjorn Hoffman.  Trial design and reporting guidelines regarding overdiagnosis would be really useful, as different definitions abound.
We should also continue to try to develop better tests to accurately quantify risk—the problem at the root of overdiagnosis. For example, as highlighted by Otis Brawley, conventional diagnostic criteria used to define most cancers are 160 years old. We urgently need better biomarkers to capture heterogeneity in risk of progression among lesions which “look” the same.
But as aptly summarised by Martin, Podolsky, and Greene, there have been many examples in the history of medicine where the advent of new diagnostic tests did lead to more, not less, overdiagnosis. These included pre-marital testing for syphilis using the (rather unreliable) Wasserman test, and harms associated with the early use of the stethoscope.  Therefore, we must be open to the possibility that better and newer tests may solve old problems, but create new ones too.
Lastly, and perhaps more crucially, we need to expand the development and use in both clinical and public health practice of appropriate communication tools to support informed decision making by patients, as part of patient centred care.
Some patients value the certainty of eliminating a future health risk above and beyond treatment related inconvenience and potential harm, and vice versa. In the late 1990s about 4 in 10 women would have opted for treatment of ductal carcinoma in situ even if the risk of progression was as low as 1%—which however also means 6 in 10 women would have not. At the conference, Fiona Miller (Toronto) and Michael Pignone (Chapel Hill) reported on discrete choice experiments exploring diagnosis/overdiagnosis acceptability trade-offs for the detection of either congenital syndromes or prostate cancer. Their findings confirmed that attitudes to overdiagnosis vary, with very substantial proportions of the public willing to accept relatively large potential for overdiagnosis. [4,5]
Although improvements in methodology and biomarker development would always be welcome, advances towards informed decision making are achievable now. If all patients were able to make perfectly informed decisions about using (or not using) tests and treatments, the debate about potential overdiagnosis and overtreatment would have been much less critical, if not obsolete. These realisations could perhaps help to bring members of the scientific community currently divided by the issue of overdiagnosis closer, faster than it would have otherwise been possible.
Georgios Lyratzopoulos (@GLyratzopoulos) is a public health and health services researcher working at the Cambridge Centre for Health Services Research. He focuses on the earlier diagnosis of cancer, and other aspects of cancer healthcare quality and epidemiology.
Funding declaration: GL is supported by a post doctoral fellowship award by the National Institute for Health Research (NIHR PDF-2011-04-047). The views expressed in this publication are those of the author and not necessarily those of the NHS, the National Institute for Health Research, or the Department of Health.
Conflict of interest statement: I declare that that I have read and understood the BMJ Group policy on declaration of interests and I hereby declare no conflicts of interest in respect of this blog.
1) For anyone not at the conference, this BMJ paper covers similar ground.
2) Abstract #77. Hofmann B. Conceptual challenges lurking behind the problems with measuring overdiagnosis: towards a more robust definition of overdiagnosis.
3) Abstract #119. Martin SA, Podolsky SH, Greene JA. Overdiagnosis and overtreatment over time: historical perspective of a very modern problem.
4) Abstract #116. Cressman C, Miller FA, Hayeems RZ, Bombard Y, Barg C, Carroll JC, Brenda Wilson B, Little J, Avard D, Allanson J, Chakraborty P, Giguere Y, Regier DA. How do citizens balance the benefits and burdens of newborn screening? A public engagement survey.
5) Abstract #53. Pignone MP, Lewis CL, Sheridan SL, Crutchfield T, Hawley ST, Brenner A, Howard K. Using a discrete choice experiment to communicate overdiagnosis in PSA screening.