Value of Screening Mammography

Several months ago I sent an email which described recent studies questioning the value of screening mammography. Replies from radiologists who do mammography expressed surprise, unhappiness and even convinced disagreement.

One of the problems with the evaluation of studies on mammography is that they are often done or sponsored by those with financial or professional advantage from the examination. The big pushers are usually radiologists who have devoted their careers to mammography. Evaluations of studies on drugs done or sponsored by drug companies have showed strong bias towards advocating their product.

JOURNAL WATCH has a review of a recent study from OBSTETRICS AND GYNECOLOGY, a major peer reviewed journal, which did a paired study of Sweden vs. Norway, Ireland vs. No. Ireland and The Netherlands vs. Belgium. In each of these pairs nationwide mammography was implemented by 1990 in one and substantially later in the other. All 6 countries showed a substantial decrease in breast cancer mortality between 1989 and 2006. For example -24% in Norway and -16% in Sweden but the decreases were no more in the fully screened countries (Sweden started full screening much earlier than Norway.) A similar study of cervical cancer screening in the Nordic counties showed that nationwide screening was highly correlated with decrease in mortality from cervical cancer. Countries which implemented earlier screening showed a much greater decrease in cervical cancer mortality. The reviewer concludes that a decrease in mortality from breast cancer due to mammography has not been shown, and that recent decreases in mortality from breast cancer in developed countries can be explained by changes in treatment, not by earlier diagnosis through mammography.

Mammography screening is very expensive nationally, leads to many unnecessary work ups with anxiety, biopsies and even surgery, radiation or chemotherapy for those who don't need it. Every radiologist, surgeon, clinician can cite examples of early diagnosis of breast cancer through mammography followed by appropriate therapy with long term survival, perhaps cure. The problem is that this does not show that this test is of any value. My suggestion to women is to get screening mammograms if they will be anxious or unhappy without them, but not to get them because they believe that mammography is definitely shown to improve their chance of not dying due to breast cancer. Mammography may be of value but the large number of studies done on the subject has not shown it convincingly. Those who get screening mammograms are guaranteed a much greater chance of unnecessary expensive and, perhaps dangerous, work ups with the associated anguish involved.