Breast Cancer Screening: Why Doctors Keep Changing Their Minds

UPDATE 11/18/2009:

Today’s New York Times includes an interesting table that reviews the differences in the lifetime number of mammograms, false positives, number of cancer deaths, etc. between starting routine screening at age 50 versus 40. Of course, this table, as well as the recommendations, is directed to women who do not have an increased risk for breast cancer such as a family history. Click here to go to the New York Times Web site and view the table.

It may seem like scientists and doctors are continually changing their minds about health benefits and prevention recommendations. One day something is good for you — then the next day a study comes out to say it’s bad. Before this week, women were supposed to get routine mammograms after the age of 40, but now a panel of experts says it’s better to wait until 50.

Breast cancer is the second leading cause of cancer death among women in the United States. According to the National Cancer Institute, approximately 200,000 new cases will be discovered in 2009, with over 40,000 deaths. Widespread screening through mammograms, clinical breast exams or breast self-examination is used to detect pre-symptomatic breast cancers in millions of women. These methods, along with treatment advances, are credited with the significant reductions in breast cancer mortality.

That is why many advocates were surprised yesterday when the U.S. Preventive Services Task Force of the Department of Health and Human Services recommended reducing screening. In an article published in the Annals of Internal Medicine, the task force recommended waiting until age 50 (instead of 40) for biennial (not annual) mammogram screenings. The group also recommended against teaching breast self-examination, finding no benefit to this practice, and suggested that mammograms for women over 75 might not be necessary, arguing that “current evidence is insufficient to assess benefits and harms.”

As expected with a major change in preventative guidelines, many breast cancer advocates and doctors vehemently disagree with the recommendations. Some question their validity. Others accuse the group of politics, trying to reduce health care costs while the Obama administration is focused on health care reform. But the new guidelines were based on published research as well as two studies the task force commissioned. The task force also cited concerns about the downside to overscreening. False positives can result in biopsies and repeated diagnostic tests, creating psychological stress and extreme anxiety.

These guideline changes and new expert recommendations can often be frustrating and confusing to patients and consumers. But our understanding of the complex systems and processes that make up the human body is still quite basic, and scientists and doctors are just beginning to understand the best ways to diagnose and treat illness. This is why having a flexible system that continually updates treatments to reflect new biomedical research is a good thing.

Kirstin Matthews is a fellow in science and technology policy at the Baker Institute. Her research focuses on the intersection between traditional biomedical research and public policy. Matthews’ current projects include the Baker Institute International Stem Cell Policy Program, the Civic Scientist Lecture Series and policy studies in research and development funding, genomics and climate change.