Public not informed about dangers of overdiagnosis

May 21, 2015

A new national survey has found 90% of people have not been told by their doctors about the risk of overdiagnosis, and 80% feel the ties between pharmaceutical companies and doctors on medical panels that define disease are 'inappropriate'.

The survey, conducted by Bond University's Centre for Research in Evidence-Based Practice and published in the global scientific journal PLOS ONE today (Thursday, May 21), is the first of its kind anywhere in the world to ask the general community about their views on the issues.

The telephone survey, a collaboration with University of Sydney, included 500 Australians and looked at the increasingly recognised problem of overdiagnosis, where patients are being diagnosed with diseases that will never cause them harm.

Bond University senior research fellow Dr Ray Moynihan, lead author of the study, said overdiagnosis was often the result of healthy people being screened for diseases such as breast or prostate cancer and could be harmful due to unnecessary labelling and treatment.

The national survey asked people who had been screened for breast and prostate cancer if they were informed of the risk of overdiagnosis, with over 80% of those screened for prostate cancer and almost 90% of those screened for breast cancer revealing they were not told about the risk.

Overall, only one in ten people said they had ever been told about overdiagnosis, and 93% of those surveyed wanted to see people given information on the harms of screening – including overdiagnosis - as well as its benefits.

The survey also questioned people about whether they felt it was appropriate for doctors with financial ties to drug companies to be members of panels that define disease and often expand the numbers of people labelled as sick - one of the drivers of the problem of overdiagnosis.

It found 78% of people felt these ties were inappropriate, with the majority of those (72%) saying they were “completely or mostly inappropriate”.   Furthermore, 55% of people felt there should be no members on panels with ties to drug companies and 36% said only a minority of members with these links on panels would be acceptable.

Dr Moynihan said the survey confirmed patients needed to be better informed about both the benefits and harms of screening, tests and treatments, and sent a clear message about the community's view on doctors' involvement with pharmaceutical companies.

“Our survey results reinforce calls to better inform the community about the real dangers of overdiagnosis,” he said.

"There is growing recognition that along with the benefits of saving lives, screening programs can cause some people harm, including overdiagnosis.

"The issue is also linked to that of the relationship between doctors and pharmaceutical companies, as disease definitions are often widened to include people with mild problems or at very low risk of illness - therefore turning previously healthy people in patients.

"The survey results add weight to recommendations that influential medical panels should be free of financial conflicts of interest."

A recent inquiry in the United Kingdom estimated 1 in 5 cancers diagnosed via breast cancer screening may be “overdiagnosed” – meaning the cancers would never go on to harm the women (1). A recent US analysis in Health Affairs estimated that for breast cancer screening alone, along with screening benefits, more than 20,000 women a year in the US may be overdiagnosed, at a cost of more than US $1 billion (2).

The United States Preventive Services Task Force estimates as many as 1 in 2 prostate cancers detected by screening may be overdiagnosed (3).

Dr Moynihan said previous research had also found panels of experts that made decisions on the definitions of common conditions, including high blood pressure, depression and arthritis, often expanded definitions, for example by creating “pre-diseases” that turn millions more formerly healthy people into patients (4).

Almost 75% of these panel members have financial relationships like consulting or speaking for the drug companies that sell medicines for the same conditions, contrary to recommendations from the influential Institute of Medicine (5).

Moynihan will be a keynote speaker at the Preventing Overdiagnosis scientific conference, being held at the National Cancer Institute near Washington DC in September this year.

References:

(1)The benefits and harms of breast cancer screening: an independent review. Lancet 2012;380: 1778–1786;

(2) National Expenditure For False-Positive Mammograms And Breast Cancer Overdiagnoses Estimated At $4 Billion A Year. Health Affairs. 2015;34:576–583;

(3)Screening for Prostate Cancer: US Preventive Services Task Force Recommendation Statement. Ann Intern Med. 2012;157: 120-134 ;

(4) Expanding disease definitions in guidelines and expert panel ties to industry: a cross-sectional study of common conditions in the United States. PLoS Med. 2013;10: e1001500;

(5)IOM. Clinical practice guidelines we can trust. Washington (D.C.): The National Academies Press; 2011;