Public doesn't understand 'overdiagnosis'

The study, led by a team at Cancer Research UK's Health Behaviour Research Centre at UCL, is the first to investigate whether the UK public understands the term.

Overdiagnosis occurs when a disease is detected but would never have gone on to cause any harm during a person's lifetime. This can happen with some cancers because they are sometimes slow-growing and unlikely to cause harm, whereas others are fast-growing and aggressive.

Although it is vital to pick up aggressive cancers early to increase the chances that treatment is effective, detecting slow-growing cancers can lead to unnecessary anxiety and treatment.

It's not yet always possible to distinguish between the two kinds of cancer at the time of diagnosis. This is why it's important that people are given a chance to make informed decisions about taking part in screening and treatment options.

Overdiagnosis can sometimes happen through breast cancer screening and the PSA test used for prostate cancer, but can also occur with other types of cancer and other conditions.

Almost 400 people, aged between 50-70 took part in an online survey where they were asked if they had seen or heard of the term 'overdiagnosis' and what they thought it meant.

The researchers found that 70 per cent (273 people) said they had not heard the term before, and only 2.6 per cent of all those surveyed (10 people) correctly explained what the term meant.

Of those who had heard of overdiagnosis before less than eight per cent (7.7 per cent) accurately explained the term.

Previous research has shown that around one in four women diagnosed with breast cancer through screening are overdiagnosed.

Lead author, Dr Alex Ghanouni, research associate at Cancer Research UK's Health Behaviour Research Centre at UCL, said: "This is the first time anyone has looked at whether or not people in the UK understand what overdiagnosis means -- and it turns out that most people are in the dark. If we want to change this, it's crucial that we start talking about overdiagnosis more to help the public make more informed decisions about their health."

Dr Julie Sharp, head of health and patient information at Cancer Research UK, said: "Early diagnosis is important but we do need to get better at distinguishing those cancers that need treatment from those that don't. Cancer Research UK's work is revealing more about the biology of cancer, which will help identify the hallmarks of more aggressive cancers and improve testing.

"Overdiagnosis is a difficult concept to explain but a better understanding of how different cancers grow and develop will help us paint a clearer picture and give people better information."