Did the American Cancer Society really change its tune on screening?
To hear the New York Times tell it, the American Cancer Society has just had an epiphany about screening for breast and prostate cancer: The benefits of catching some cancers early must be weighed against the harms of treating tumors that aren’t life-threatening.
“Cancer Society, in Shift, Has Concerns on Screenings” is the headline at the top of today's front page. In the story, the society’s chief medical officer, Dr. Otis Brawley, makes this statement: “I’m admitting that American medicine has overpromised when it comes to screening. The advantages to screening have been exaggerated.”
It may sound shocking, but it’s hardly a new position. Since Brawley assumed his post in November 2007, he has often made the case that the net benefit of screening isn’t the same for all types of cancers.
For instance, in April 2008 he coauthored a report in CA, the cancer society’s journal for physicians, that highlighted the same concerns about breast cancer screening that are mentioned in the New York Times report:
“Women also should be told about the limitations of mammography, specifically that mammography will not detect all breast cancers and that some breast cancers detected with mammography may still have poor prognoses. Further, women should be informed about the potential harms associated with mammographic screening, including false positives and the possibility of undergoing a biopsy for abnormalities that prove to be benign.”
A recent story in the Los Angeles Times Health section described these limitations quite nicely. As many as 1 in 3 routine mammograms identifies a cancer that would never become life-threatening and might regress on its own, according to a study published in July in the British Medical Journal. But since there’s no way to distinguish dangerous breast cancers from harmless ones, women undergo treatment that is painful, toxic, and unnecessary.
The story also noted a 2008 study of 42,238 Norwegian women that quantified the benefits and risks like this: “For every 2,000 women screened by mammography over 10 years, one will avoid dying from breast cancer and 10 others will receive treatments for a cancer that would have never become life-threatening.”
Despite these drawbacks, the American Cancer Society recommends that women over age 40 get annual mammograms. In a statement issued today to clear up the confusion created by the New York Times story, Brawley said that despite its imperfections, “the bottom line is that mammography has helped avert deaths from breast cancer, and we can make more progress against the disease if more women age 40 and older get an annual mammogram.”
When it comes to prostate cancer, the American Cancer Society’s position for the last 12 years has been that screening tests should be available to all men over age 50, not that all men should take them. Brawley reiterated that position as well.
Dr. Len Lichtenfeld, the society's deputy chief medical officer, was much more straightforward in a post this afternoon on his informative cancer blog titled "Where's the News?":
"The American Cancer Society is not working on any stealth project to change commentary on our website to emphasize the shortcomings and risks of screening. If we are, I would know about it, and I haven’t heard anything about such a plan. We don’t have to. You see, we already discuss these issues right there in plain view, including on this blog."
The New York Times article was prompted by a study published today in the Journal of the American Medical Assn. that urges clinicians to reconsider the utility of early screening for breast and prostate cancer. Though routine screening has identified more early-stage tumors, it hasn’t translated into a corresponding decrease in aggressive tumors, according to Dr. Laura Esserman and Yiwey Shieh of UC San Francisco School of Medicine and Dr. Ian Thompson of University of Texas Health Science Center in San Antonio.
It’s hardly surprising that the notion of de-emphasizing early screening touched a nerve. The idea that cancer deaths can be averted through early detection and treatment is so compelling that a $45-million bill to “increase public awareness regarding the threats posed by breast cancer to young women" has 372 co-sponsors in the U.S. House of Representatives. Yet it is opposed by the National Breast Cancer Coalition because it would probably lead to more unnecessary biopsies and ultimately do more harm than good. Dartmouth researchers Steven Woloshin and Lisa M. Schwartz made the case against the well-intentioned bill this summer on the Los Angeles Times’ Opinion page.
Cancer researchers also chimed in today to lend their support for Brawley’s controversial -- if not new -- position.
“It's tough for the American Cancer Society to have a simple message on screening because pap smears and colonoscopies do work,” said Dr. Patricia Ganz, director of cancer prevention and control research at UCLA's Jonsson Comprehensive Cancer Center. “However, the evidence is not there for mammograms and prostate cancer screening.”
-- Karen Kaplan
Photo: The idea that routine mammograms are overrated isn't exactly new. Credit: Rui Vieira / PA Wire