Science 19 February 2010:
Vol. 327. no. 5968, pp. 936 - 938
DOI: 10.1126/science.327.5968.936
Science magazine provides a news article on a dispute among epidemiologists and medical practitioners as to whether breast mammographs should be routinely given to women between 50 and 60 years of age. There are a number of studies done in different locations at different times, all of which seem to indicate a small reduction in breast cancer mortality from women in that age group who receive screening. On the other hand, there are a lot of false positives, each of which is likely to cause anxiety to a woman and the time and expense of follow-on treatment. Not included is the risk due to radiation exposure from repeated x-ray examinations.
The decision on the public policy is presumably based on the comparison not only of the benefits, risks and costs of the procedure, but on whether the resources that would be used for breast cancer screening might better be used for alternative interventions.
The article indicates not only that the standard-setting committees tend to have disagreements within and between committees, but that others (NGOs, medical associations, etc.) also go public with their comments seeking to influence decisions.
The epidemiological studies of course are based on average results over large numbers of women, rather than on the information provided for individuals with differing a priori risks (as might be measured by cancer rates in relatives, specific age, years since menopause, parity, etc.).
Two conclusions.
- Women should consult and be guided by their physicians, who should in turn deal with the costs and benefits of screening as perceived by the patient as well as the risks faced by that specific patient.
- Really good data systems of medical records should allow data mining to greatly improve the guidelines for breast cancer screening, as of course will improved genetic screening when it becomes available.
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