The debate over when and how often women should get mammograms was reignited Monday with the release of new guidelines that recommend that women wait until age 50 to begin getting the breast cancer screenings, and then follow up with them every other year, rather than annually.
The guidelines, issued by the influential U.S. Preventive Services Task Force (USPSTF) and published in the Annals of Internal Medicine, are based on extensive evidence showing that screening mammograms confer the greatest benefits when women get them biennially (every two years) from ages 50 to 74. For the majority of women — those whose risk of developing breast cancer is average at best — getting mammograms earlier or more often raises the likelihood of cancer scares and unnecessary follow-up treatments, but doesn’t offer extra benefits in terms of detection, the task force said.
For women older than 74, the panel said there’s insufficient scientific evidence to make a recommendation. However, the available evidence suggests that the benefits of routine mammography may be limited for older women.
The latest recommendations, which are in line with the previous guidelines released in 2009, still strongly endorse mammography for women ages 50-74. The task force also made it clear that they don’t want to discourage women in their 40s from getting mammograms – rather, they said, women should discuss the pros and cons with their doctors.
“[T]he bottom line is that mammography saves lives,” said the paper’s lead author, Jeanne S. Mandelblatt, MD, MPH, of Georgetown Lombardi Comprehensive Cancer Center, and a principal investigator with the Cancer Intervention and Surveillance Modeling Network (CISNET).
“When to start screening and how often to undergo mammography is a personal decision.”
After years of fervent activism, public health campaigns and medical practice, the mammogram has become an annual ritual for many women older than 40 in the United States. For some breast cancer advocacy groups, the benefits of that ritual have become an article of faith. So when the task force first questioned that conventional wisdom in their 2009 mammography guidelines, which said screening could start later in life and take place less often, the result was confusion and controversy.
The American College of Obstetricians and Gynecologists, whose physicians are most likely to counsel women about breast cancer screening, recommends annual mammograms starting at age 40, as does the American College of Radiology. After years of offering the same advice, the American Cancer Society changed its guidelines last year and now suggests yearly mammograms starting at age 45, switching to once every other year at age 55.
What sets the USPSTF recommendation apart is its message that the harms of screening must be balanced against the benefits. Until the task force’s recommendation, the risks of screening often weren’t part of discussions women have with their doctors about mammograms. For decades, the need to educate people about screening and the risks of cancer meant that mammograms — and other cancer screenings — tended to be presented in an almost exclusively positive light and as a mandate for anyone interested in improving their health.
Does Screening Save Lives?
The problem is, as a recent study pointed out, there is no solid evidence supporting the fact that cancer screening “saves lives” as many campaigns, particularly early on, claimed. While regular screening can, theoretically, detect cancer earlier and therefore potentially reduce the risk of dying of cancer, there’s no scientific proof that it can reduce your risk of dying early from any cause.
But ask the average woman about what cancer screening is supposed to do, and she will probably say “save lives.” It might seem like a small distinction but it’s important. Looking at overall mortality, or deaths from any cause, is the most accurate way to measure the effectiveness of screening. Just looking at screening’s effect on cancer deaths, or death rates from a specific cancer, says nothing about how long that person will live overall, since it only looks at one disease. In addition, it does not take into account any complications or side effects of the screening, including exposure to radiation and even overtreatment, that could also potentially be fatal.
Prostate cancer provides a perfect example. When prostate cancer screening became de rigeur in the 1990s, doctors didn’t realize that most of the lesions they would find would not actually need treatment. Studies now suggest that about half of men diagnosed with prostate cancer are over diagnosed, meaning they received treatment for a cancer that likely would not have ever progressed to cause symptoms or contribute to their early death. These men likely had lesions that grew so slowly that men were more likely to die of something other than prostate cancer. But many received hormone treatments since they believed that getting a diagnosis of prostate cancer meant they needed to treat it somehow, even if they didn’t have any symptoms.
That led to an increase in heart disease rates from the exposure to the well-intentioned but unneeded anti-androgen hormone therapy — and the USPSTF to recommend that men skip getting the blood test to screen for prostate cancer entirely. Other groups, like the American Urological Association, also revised their guidelines to reduce men’s exposure to the potentially harmful hormone.
The Bottom Line
In their update on mammography, the USPSTF stresses that they want younger women to understand the trade-offs before deciding on the best course of action: Among every 1,000 women screened, one additional death could be prevented by starting mammograms at 40 instead of 50. But there would be 576 more false alarms and 58 additional unneeded biopsies. Also, two extra women would be overdiagnosed, treated for cancer that never would have become life-threatening.
“Compared with screening initiation at age 45 years, starting screening at age 40 years had one or fewer added deaths averted depending on interval, but more incremental harms,” they added.
While it’s frustrating to continually see new guidelines and new recommendations, it’s important to remember that the different guidelines still converge on one main point: mammography is a live-saving screening procedure when utilized correctly. Breast cancer is still the most common cancer among women living in America, with about one in eight women developing invasive breast cancer during their lifetime, according to the ACS. We need to experts to keep reviewing and evaluating programs currently in place to make sure women (and men) have everything they need when it comes to minimizing risk and finding effective treatment.