Alan Cassels is a pharmaceutical policy researcher at the University of Victoria, British Columbia, a journalist, and author of the The Cochrane Collaboration: Medicine’s Best-Kept Secret.
In mid-January, there was a flurry of news media activity focusing on breast cancer screening and the problem of overdiagnosis, particularly when breast tumors are benign but treated as if they were deadly.
Stories in Forbes, NBC, USA Today, Medscape and Time Magazine covered a Danish study that found up to a third of breast cancers detected via mammography “would never have caused a noticeable health problem or led to death – and are therefore examples of overdiagnosis,” as Reuters put it.
While all these stories did a pretty good job of highlighting the changing landscape of recommendations, they tended to gloss over the very political nature of breast cancer screening, including who stands to gain financially from more aggressive screening and how those incentives may impact national screening recommendations in the U.S. and abroad.
In the U.S., it is clear that our “pink ribbon” culture is wildly enamored with mammography, and relies heavily on the “early detection saves lives” meme that generates interest and donors. As a result, the money, reputations and infrastructure tied to mammography wield an undeniable influence on decision-making and health policies. And, expected growth in the mammography market–discussed in this recent market analysis–is high, even as some public health agencies are generally saying we should be more selective to whom we offer breast cancer screening.
So what’s a woman to do? That’s ultimately an individual decision, but here is one key detail you’re unlikely to see in news coverage: The U.S. groups that endorse early mammography–usually starting at age 40–are the same groups that benefit from revenues from the breast cancer industry, including the American College of Radiology (who owns the trademark for the Mammography Saves Lives campaign), and the National Breast Cancer Foundation. Companies involved include Siemens, which sponsors American Cancer Society’s Make Strides Against Breast Cancer campaign, and General Electric, which sponsors the American Breast Cancer Foundation. They are two of the main manufacturers of the devices used in mammography.
Meanwhile, independent groups, such as the United States Preventive Services Task Force (USPSTF), say that the net benefit is small in women over 40, and they recommend that women 50 to 74 have mammograms every two years. The USPSTF is made up of independent scientists who assess the value of screening, are not allowed to make financial arrangements with providers, and do not consider cost impact in their analysis. In Canada, the Canadian Task Force on Preventive Healthcare has similar recommendations to the USPSTF– but they were actually more aggressive in attempting to scale back the overuse of breast cancer screening.
Breast Cancer Action, an advocacy group in the U.S. which takes no donations from drug or device companies, is one of the more outspoken cancer charities and has produced solid, evidence-based recommendations on mammography. Their 50+ recommendation jives with evidence that goes back as far 2002, when a Swedish meta-analysis of research published in the Lancet determined that there was unlikely to be any benefit in screening women under the age of 55.
Yet, the 40+ recommendations persists, even in the face of growing evidence that the benefits of starting at age 40 are small and the harms considerable. One provocative challenge was made in 2011 by Dr. Peter Gotzsche, head of the Nordic Cochrane Centre, and one of the world’s foremost experts on breast cancer screening. In an editorial in the Canadian Medical Association Journal titled “Time to Stop Mammography Screening?” he explained that “the best method we have to reduce the risk of breast cancer is to stop the screening program.” He added that the “level of overdiagnosis in countries with organized screening programs is about 50%.” (While estimates differ, depending on how things are measured, the level of overdiagnosis found in the most recent Danish study was about 33%.)
Also, he added, “if screening had been a drug, it would have been withdrawn from the market. Thus, which country will be first to stop mammography screening?”
So far, “no one has abandoned breast screening yet. But independent panels in Switzerland and France have recommended their governments to do this,” said Karsten Jorgensen, the lead author of the Danish study (and a colleague of Peter Gotzsche). Both the Swiss and the French panels wanted to see new restrictions on mammography programs, and, for example, the Swiss board recommended that no new systematic mammography screening programs be introduced and that a time limit be placed on existing programs.
Notably, Time Magazine mentioned the situation in other countries, telling readers that the French National Cancer Institute is set “to launch a year-long inquiry into how to improve screening, and the Swiss Medical Board now advises against routine mammogram screening for most women,” The story then explains that the topic still remains “confusing and controversial” because earlier research suggested mammography was lifesaving for some women.
Jorgensen pointed me to a particular paper, in the January issue of The Breast, that gave an overview of various guidelines on breast screening and explained why recommendations differ. It mainly comes down to how the various experts interpret the science and how much weight they give to give different studies. But while the estimates vary on how many breast cancer deaths might be prevented by screening, it should be noted that no cancer screening has ever been shown to reduce overall mortality. Which is to say that women who are saved from breast cancer may be more likely to die earlier from something else.
Many of the news stories mention some of the controversy and the different recommendations from organizations, but they don’t go further to examine the conflicts of interest and the amount of money that is currently being spent on mammography in the U.S.
To its credit, the NBC story noted the political aspects of mammography and the power it has over legislators, stating “Congress has even intervened, passing legislation overriding the USPSTF guidelines and requiring that insurance companies cover screening mammograms at no cost for most women who want them.“
The crux of the issue is this: Whether to screen at the age of 40 is a personal decision for women who may make different decisions based on their personal values. Some may leap at any opportunity to receive early curative therapy — no matter how small the chance they will benefit or how great the potential harms — while many others will look at the same evidence and prefer not to know what a mammogram might find.
The choice is difficult, and journalists weighing in on the debate owe it to their readers to provide context that will help. This means not just passing along the recommendations from professional or advocacy groups, but exploring the cultural and financial influences that may have helped to shape those recommendations.