By announcing its new recommendation that all women over 40 should have yearly screening mammograms, the American College of Obstetricians and Gynecologists (ACOG) joins prominent groups like the American College of Radiology, the American Cancer Society and others who have decided to resolutely ignore the extensive evidence supporting less frequent screening in this age group.
In November 2009, the U.S. Preventive Services Task Force, an independent group of experts in prevention and primary care who are appointed by the Department of Health and Human Services, issued revised guidelines on screening mammography. After an exhaustive review of dozens of studies, the task force 1) found that yearly screening mammograms for women under 50 who have no risk factors for breast cancer offered more harm than benefit, 2) recommended that women over 50 should receive mammograms every one to two years and that 3) there was insufficient evidence to recommend routine screening for women over 75.
According to the task force findings, among women in their 40s, one breast cancer death would be averted for every 1,904 women screened regularly for 10 years. Among women in their 50s, one breast cancer death would be averted for every 1,339 women screened; and for those in their 60s, one for every 377 screened.
The task force’s overall recommendation was to endorse patient choice; “The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms."
These new guidelines incited a firestorm of controversy among breast cancer advocates, doctors and professional groups—many of whom have ties to the pharmaceutical and medical imaging industries. Accusations of health care rationing combined with impassioned stories of how women’s lives were saved by routine mammograms elicited all manner of emotional responses, including this reference to the “government takeover of health care” from Rep Marsha Blackburn from Tennessee who asserted, “This is how rationing begins. This is the little toe in the edge of the water; this is when you start getting a bureaucrat between you and your physician.”
Less than a month later the Senate approved an amendment to the health care reform bill that would guarantee coverage of mammograms for all women who seek them out.
At the time, ACOG’s recommendation was that women 40 and older should have screening mammograms every one to two years—as the USPSTF itself suggested in 2007. Why then, has the group decided at this late stage to not only ignore the task force’s advice but recommend even more frequent screening than before?
“[T]he change in mammography screening for women beginning at age 40 is based on three factors” according to an ACOG press release: “the incidence of breast cancer, the sojourn time for breast cancer growth, and the potential to reduce the number of deaths from it.”
The “sojourn time” refers to the time period between when a very small breast cancer may be detected by a mammogram and when it grows big enough to become symptomatic.
The ACOG press release informs us that “Although the sojourn time of individual cancers can vary, the greatest predictor is age. Women ages 40-49 have the shortest average sojourn time (2-2.4 years), while women ages 70-74 have the longest average sojourn time (4-4.1 years).” The idea is that tumors detected in younger women grow faster and are more invasive than those that occur in older women.
This information about sojourn time is based primarily on computer simulations and theoretical calculations—unfortunately, no one really knows how to predict which tiny lesions picked up by mammography will progress to harmful or deadly tumors. In fact, in 2009 researchers writing in the British Medical Journal found that “one in three breast cancers detected in a population offered organized screening is over‐diagnosed”—meaning that one-third of the lesions detected were harmless and unlikely to progress any further. Meanwhile, the women in whom they were found endured further testing, biopsies and in some cases surgery, chemotherapy and/or radiation they didn’t need.
The rationale of ACOG is further confusing because in the same press release the group adds; “The incidence of breast cancer in the US declined 2% each year between 1999 and 2006, and deaths from breast cancer have also declined steadily over the past two decades. Evidence suggests the drop in breast cancer rates is most likely due to fewer women getting mammograms and therefore not being diagnosed, as well as a significant drop in women using hormone therapy for menopausal symptoms.” Isn’t this essentially saying that the drop in incidence of breast cancer is in part due to fewer women getting mammograms? But meanwhile the death rate has not gone up…work it out for yourself—why do we want more mammography?
The news about ACOG’s new recommendation was reported with little analysis in much of the media. On his blog HealthNewsReview, Gary Schwitzer provides a rundown of the range of reporting on this issue, from blatantly biased pieces supporting more frequent mammography (Schwitzer quotes a “tweet” from CNN’s Elizabeth Cohen that reads, "To all my sisters over 40: we need mammos once a year. 1 out of 3 don't get em, so spread the word.") to more balanced reports from Reuters and the Boston Globe that cite critics of ACOG’s blanket endorsement of screening.
In the Reuters Health article, for example, USPSTF’s Michael LeFevre uses actual evidence-based figures to lay out a more thoughtful analysis of the risks and benefits associated with routine mammogram screening in younger women. “One in eight women will get breast cancer during her life, experts agree. For every 1,000 women who are 40 years old, LeFevre said, 30 would be expected to die of breast cancer if they never have a mammogram.
“If those 1,000 women are screened every other year between age 50 and 75, that number drops to 23 deaths. Starting screening in the same group at 40 would save one additional life, meaning 22 would die of breast cancer, on average.”
But, LeFevre continues, "that small benefit comes with a significant false positive rate, which results in additional testing, including unnecessary biopsies and associated pain and anxiety."
As to how he will counsel his own patients, LeFevre told Reuters, "my bottom line is that I will discuss mammography at age 40, I will recommend and encourage at age 50 and I will strongly encourage at age 60."
Mammography is an issue that continues to percolate through the health care debate over the benefits of screening tests vs. the harms of over-treatment. From the minute that the USPTFS came out with their new recommendations there were vocal critics of the guidelines from groups with a clear vested interest in screening—the American College of Radiologists comes to mind—and from opponents of the health reform law who wanted to use the issue to foment fears of rationing. Patient advocates from mainstream breast cancer groups like the Susan B. Komen foundation (which accepts financing from drug companies that sell the very drugs used to treat early stage tumors found through mammography) also insisted that the task force was simply wrong in not strongly recommending yearly mammograms for women in their 40’s. Many women remain convinced that mammography, early and yearly, saves lives and is a key factor in the decreasing death rate from breast cancer in this country.
The real issue is that the decision to undergo mammography should be a personal one and free from conflict of interest. That’s why the recommendations from the USPSTF—a group specifically prohibited from considering cost in developing their guidelines—should be a major part of that decision. Ned Calonge, the current chairman of the USPSTF has warned, “The introduction of politics into the process is a real danger. We need to make sure the Task Force’s evaluations remain free from advocacy, politics, and economics.”
Women in their 40’s must be making informed choices, provided with the latest evidence-based information about the real risks and benefits of mammography. It is not enough to depend on anecdotes from friends, advice from doctors who continue to pass on outdated information and messages from the breast cancer industry that encourage testing and more testing without worrying about false positives and overtreatment. When a professional group like ACOG issues an outright endorsement of recommendations not backed by evidence, it’s hard to argue that patients will actually be making truly informed decisions about care.