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Value-based decision-making: Breast cancer screening

Value-based decision-making

However obsessed we may become about evidence-based decision-making, decisions are never (or rarely) based solely on evidence alone. Two other factors have to be taken into account - resources (pretty obvious, this), and values (how individuals and society makes judgements about what they want). When different groups have different judgements about evidence, and perhaps different judgements about values, then life can become very difficult.

Breast cancer screening in the USA

The way in which values can influence decisions, even when the evidence is of very high quality, is illustrated by the recent twisting and turning in the USA about breast cancer screening in women under 40 years. An NIH Consensus Conference concluded that routine mammography was not indicated universally for women in their forties [1]. Sections of the medical, political and media world went ballistic, with accusations of fraud, of condemning women to death, and the New York Times and Congress made up their own minds and called for screening to be introduced [2].

The National Cancer Institute's Advisory Board reviewed the decision, and on a 17-1 vote recommended mammographic screening every one to two years for women aged 40 to 49 years who are at average risk.

UK/US - snails and evangelists

The evidence is the same, but the interpretation differs. The US panel has made a decision that no UK panel would be likely to make. In the US they might argue that such a decision in the UK was based on lack of resources which influenced our decision. Or they might argue that we Brits were effete, and unwilling to join battle with cancer. We in turn might recognise the "can-do, must-do" attitude of a US frontier society; if there is a chance of doing something, then it should be attempted.

Sober thoughts on making decisions

But one helpful outcome has been thoughtful words on the pitfalls of consensus meetings and statements in some of the difficult areas of medicine [3, 4]. Just as scientific experts must be wary of imposing their values on the public, the public (or at least their decision makers) need to be more deeply involved in helping to assess the scientific evidence, and especially the balance between good and harm. Perhaps as well we need more recognition that where the effectiveness of any medical intervention is small, the likelihood will be that experts will disagree.


  1. Journal of the American Medical Association 1997 277: 519-20.
  2. Final mammography recommendation? Journal of the American Medical Association 1997 277: 1181.
  3. SW Fletcher. Whither scientific deliberation in health policy recommendations? Alice in Wonderland of breast cancer screening. New England Journal of Medicine 1997 336: 1180-3.
  4. SG Pauker, JP Kassirer. Contentious screening decisions. Does the choice matter? New England Journal of Medicine 1997 336: 1243-4.

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