The increasingly recognised problem of overdiagnosis happens when a person is diagnosed with a disease that will never cause them any harm, often as a result of being screened for diseases such as breast or prostate cancer. Overdiagnosis can be harmful due to unnecessary labelling and treatment.
The national phone survey of 500 Australians is the first time the public has been asked about their knowledge and views on overdiagnosis.
Together with their life saving benefits, screening programs can cause people harm, including overdiagnosis. A recent inquiry in the UK estimated that one in five cancers diagnosed through breast cancer screening may be “overdiagnosed” – meaning the cancers would never go on to harm the women. For prostate cancer screening, the United States Preventive Services Task Force esitmates as many as 1 in 2 cancers may be overdiagnosed.
Given this evidence, the national survey asked people if they had been screened for breast or prostate cancer, and if so, whether they had been informed about the risk of overdiagnosis.
For prostate cancer, over 80 per cent of men screened said they were not told about the risk of overdiagnosis, and for breast cancer, almost 90 per cent said they were not informed about overdiagnosis.
Overall only one in ten people said they’d been told about overdiagnosis, and 93 per cent of those surveyed wanted to see people given information on the harms of screening, as well as its benefits.
Research author Professor Kirsten McCaffery of the University of Sydney says: “Our survey results show we need to better inform the community about the harms and benefits of screening, including the important harm of overdiagnosis.”
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.
Another contributor to overdiagnosis is the widening of definitions that include people with mild problems or those at very low risk of illness, often by experts with financial conflicts of interest. Nearly 80 per cent of people surveyed believed it was inappropriate for experts who define disease to have financial relationships with pharmaceutical companies.
Media enquiries: Dan Gaffney, University of Sydney 048 100 4782