Mammography and the politics of randomised controlled trials
The debate over screening for breast cancer among women in their 40s has assumed an importance out of proportion to its potential impact on public health, argues Jane Wells from the Institute of Health Sciences at the University of Oxford in this week's BMJ. Randomised controlled trials of the effectiveness of such screening have found that it significantly reduces mortality in women over 50 years but that the benefit is smaller and the associated harm is greater in younger women.
Wells argues that because breast cancer is an emotive issue, certain professionals have used public fear to their advantage. For example, some politicians in pursuit of votes may act in ways that reflect how they believe the public wishes them to act, irrespective of the scientific evidence.
The author concludes that "the mammography story illustrates some of the many
obstacles to putting research findings into clinical practice. When trials do
not give an unequivocal answer, when politicians and interest groups become
involved and when the professionals responsible for promoting the public's best
interest fail to do so, objectivity is likely to suffer."
Dr Jane Wells, Specialist Registrar in Public Health Medicine, Health Services Research Unit, Department f Public Health, Institute of Health Sciences, University of Oxford, Oxford email:firstname.lastname@example.org
(Contact through Jill Shepherd at BMJ press office Thursday 29 - Friday 30