Jan 29 2009
The information about breast screening sent to women in the United Kingdom has serious shortcomings and should not be used as a basis for informed consent, warn researchers in a paper published on bmj.com.
Two years ago, Peter Gøtzsche and colleagues at the Nordic Cochrane Centre surveyed breast screening leaflets given to women in six countries, including the UK. They showed that the most important harms of screening (over-diagnosis and over-treatment of healthy women) were not mentioned and that other harms were often either omitted or downplayed.
Now they argue that, although the UK leaflet was later updated, the contents remain essentially the same.
The UK leaflet has the authoritative title "Breast screening: the facts" which suggests that the information can be trusted and is helpful for women when they decide whether to participate in screening, say the authors. However, the leaflet has little information about harms and emphasises the benefits.
For example, the major harm of screening – treatment of healthy people for a cancer disease they do not have – is not mentioned. This, they argue, is in violation of guidelines and laws for informed consent.
Other harms not mentioned or not explained fully in the leaflet include false positive diagnoses (abnormalities detected during screening that often lead to repeat testing to rule out cancer), risks of radiotherapy, and carcinoma in situ (a precursor to cancer).
Meanwhile, there are no reservations in the leaflet about screening older women, say the authors, although it has not been shown that screening these women decreases their risk of dying from breast cancer.
The one-sided propaganda about breast screening is a global phenomenon that has resulted in misconceptions about its effects, they warn. New evidence that demonstrated less benefit than what was previously thought, and substantially more harm, has largely been ignored.
There is also a potential conflict of interest when those who provide the information are responsible for the success of the screening programme. They suggest that the responsibility for the programmes must be separated from the responsibility for the information material and that information materials should be carefully tested among general practitioners and lay people.
As a result of their analyses, the authors have developed a leaflet that is based on the latest scientific evidence and describes benefits and harms in numbers that are readily understood. They hope that this leaflet gives sufficient information to enable a woman – together with her family and her general practitioner – to decide whether participation in screening is right for her.