Invitations to mammography screening: basis for an informed consent?

Article type
Authors
Juhl Jorgensen K, Gotzsche P
Abstract
Background: Participation on the basis of informed consent is a prerequisite for breast cancer screening programs. However, studies have shown that invited women have a poor knowledge of benefits and harms of mammography screening and that information in pamphlets and on web sites is incomplete and biased.

Objectives: To examine the information in invitations to mammography screening.

Methods: Cross sectional study using a data sheet with 17 information items. Thirty invitations to mammography screening were collected from Australia, Canada, Denmark, New Zealand, Norway, Sweden and the UK.

Results: A date of appointment was issued in 21/30 (70%) of invitations and 19/30 (63%) included a pamphlet. The invitations included a median of 2 out of 17 information items, ranging from 0 in Sweden to 6 in New Zealand. Benefits were presented as a relative risk reduction in breast cancer mortality, never as an absolute risk reduction or number needed to screen to prevent one death from breast cancer. Recall rates referred to each screening round, never to the accumulated risk. The most important harms, overdiagnosis and overtreatment, and the increased risk of invasive procedures or getting a diagnosis of carcinoma in situ were not mentioned in any of the invitations. The risk of psychological stress due to false positive results was left out in 24/30 (80%). Pain at mammography was mentioned in 16 but downplayed in 8. Many invitations were worded as direct pleas for participation and the language of some letters could be perceived as persuasive and intimidating. Regular self-examination and/or clinical breast examinations were recommended in 14/30 (47%) of invitations, despite the lack of evidence of a beneficial effect.

Conclusions: Informed consent is generally not respected. Invitations are used as a means to persuade women to participate in screening programs, not to give a balanced account on benefits and harms that allows individual decision-making. The inherent conflict of interest between securing high uptake and supplying balanced information suggests that those working with the program should not be the same as those who inform about benefits and harms.