By Karuna Jaggar, Executive Director
A few months ago, in the middle of breast cancer awareness month, the American Cancer Society (ACS) updated their breast cancer screening guidelines for women at average risk, rolling back the recommended age to begin mammography screening at 45 years of age instead of 40 and scaling back on the frequency of screening to once every two years for women age 55 and older.
After hearing “early detection is your best protection” and “screening saves lives” for decades, many women are understandably struggling to understand why, in the face of the public health crisis that is the breast cancer epidemic, the country’s largest cancer charity is recommending fewer mammograms. After all, in the 1980s women’s health activists worked hard to ensure mammograms, which were considered a core tenet of women’s healthcare, were covered by insurance companies; letting go of this hard won right can seem a sacrilege.
Around 40,000 individual women die of breast cancer each and every year. Sisters. Mothers. Daughters. Spouses. Friends. For each of these women and their loved ones breast cancer is a personal tragedy. The fact that the death rate for breast cancer has not declined significantly despite near universal awareness of the disease and decades of widespread mammography screening is a national outrage that is too rarely acknowledged.
Because we’ve all been told “screening saves lives” for decades, what I’m about to say below may sound counter-intuitive – and I need to give several important caveats, which will sound familiar to you if you’ve been with BCAction for a long time. My first caveat is that the evidence on breast cancer screening I discuss below applies only to asymptomatic women at average risk of breast cancer – not women at higher than average risk due to an inherited genetic mutation, family history of the disease, or previous cancer diagnosis. Nor does it apply to women who have symptoms of breast cancer and rightly go to get a mammogram.
My second caveat is that mammography has three uses that often get confused or conflated.
The first use of mammography is screening, which is when people at average risk of breast cancer undergo routine mammography to find cancers that are not yet symptomatic. The second use of mammography is surveillance – when people who are at a high risk of breast cancer (like Angelina Jolie, who has a BRCA mutation) undergo more frequent mammograms than the average woman. And the third use is diagnostic, which is when a woman has symptoms (like a lump she found in her breast) and then gets a mammogram and learns whether or not her symptoms are, in fact, cancer. The ACS’ guidelines, and my discussion below, apply only to the first use of mammography: routine screening for women at average risk of breast cancer who have no symptoms of the disease. If you are at high risk of the disease or find a lump in your breast, this evidence does not apply to you and you should see a doctor and get a mammogram.
So, now that I’ve given you those caveats, here’s my counter-intuitive message: the ACS’ recent shift on mammography screening is actually an important step in following the evidence on routine breast cancer screening that is long overdue. After more than 30 years of aggressively pushing routine breast cancer screening for women at average risk, the new ACS recommendations finally take a step toward acknowledging the significant harms and limited benefits of population-based mammography screening. The truth is that not only has widespread screening failed to dramatically reduce the death rate from breast cancer, it has also failed to reduce late stage diagnosis of the disease.
The premise of routine breast cancer screening is that by catching breast cancer early, before it has reached a later stage, women will be more likely to survive the disease. The philosophy behind the push to screen average risk, asymptomatic people for breast cancer is based on the assumption that breast cancer progresses in a linear fashion. While it’s true that survival outcomes are generally better for earlier stage disease, we now know that the far bigger factor in a woman’s prognosis for breast cancer is tumor type. Many activists from the metastatic community today are pointing to the fact that approximately 30% of breast cancers diagnosed at any stage will go on to metastasize.
Tumor type rather than stage is a bigger factor in prognosis. Unfortunately, there are some breast cancers that are so aggressive, it does not matter how early they’re caught, as we currently – and tragically – lack effective treatments. As the JAMA editorial accompanying the release of the new ACS guidelines makes clear, “85% of women in their 40s and 50s who die of breast cancer would have died regardless of mammography screening.” While some breast cancers are very aggressive, most are slow-growing, taking a decade or more to become detectable. Many of these slowest growing cancers would never become a problem for women and would not be found were it not for a mammogram. The harder we look, the more we will find, and these slow-growing cancers will usually be treated once they’re found.
For 30 years, the main message around breast cancer has been that breast cancer screening will help prevent women from dying of breast cancer, but studies have shown that the “early detection saves lives” mantra just isn’t true when it comes to breast cancer. In 2014, the British Medical Journal published the largest mammography study to date, finding that screening average-risk women – before they could feel a lump in their breasts – did not lead to lower breast-cancer death rates for those in their 40s and 50s. The National Cancer Institute came to a similar conclusion in an analysis of multiple mammography studies involving nearly a half-million women: “Screening for breast cancer does not affect overall mortality.” The evidence has long shown that the benefits of routine mammography screening for asymptomatic average risk women are limited at best. As the ACS’s Chief Medical Officer states clearly, “The chance that you’re going to find a cancer and save a life is actually very small.”
So, what happens if you treat a cancer that isn’t life-threatening? Far from being “better safe than sorry,” treating a cancer that is not life-threatening leads to significant harm for women. A little discussed tragedy is the fact that tens of thousands of women are treated unnecessarily for breast cancer each year because of routine mammography screening programs.
Overdiagnosis, which is when screening finds asymptomatic cancers which would otherwise not have been found, happens when we look for early forms of disease via routine mammography screening programs. According to the ACS Special Communication accompanying their new guidelines, estimates on overdiagnosis of breast cancers found through screening vary widely, from less than 5% to more than 50%. Overdiagnosis, in turn, leads to overtreatment, which is the treatment of disease that would not lead to death, essentially giving too much treatment without benefit to the patient.
The most widely accepted estimates are that about one in five women whose breast cancers are found via routine mammography screening end up receiving treatment that does not benefit them. These women suffer the immediate effects of surgery, radiation, chemotherapy and other systemic therapies. Less often discussed, these women also experience a range of long-term impacts that include physical and health harms such as disability, neuropathy, lymphedema, heart disease, and secondary cancers; financial consequences from medical debt to un- and under-employment; the psychological toll of having been diagnosed with cancer; and other quality of life impacts of treatment such as issues with sexuality, “chemobrain,” and others.
That 1 in 5 women treated for breast cancer may have gone through all of that for nothing is devastating on a personal and societal level. Women who have felt that their mammogram saved their life may suddenly wonder if they were unnecessarily harmed by screening. Doctors who seek to cure are forced to look directly at the harms of treatment they provide. And we all must contend with the fact that the solution we were promised – screening, early and often– is not ending the breast cancer epidemic.
It is only possible to recognize overdiagnosis and overtreatment at a systemic level, across populations, but it is impossible to do so at an individual level. Doctors cannot look at their patients and know which patients didn’t need treatment—and so they tend to say that every patient is better for treatment. Women cannot know if their life was saved or not – and understandably tend to think that the mammogram that found their cancer saved their life.
It’s devastating. And too often defenders of routine screening invite us to look away from these truths by talking about the harms of false positives while ignoring or downplaying overdiagnosis and overtreatment. False positives are suspicious findings that turn out not to be cancer. Each year hundreds of thousands of women are asked to return for another mammogram to get additional images and some will get biopsies. Many defenders of routine mammography screening suggest that the price of a few call-backs and biopsies is a small price to pay for saving women’s lives. Ultimately that is a decision each woman must make for herself, and it’s sobering that around half of women who are screened via mammography over ten years will end up with a false positive reading that results in invasive procedures, additional radiation exposure, increased expense as well as stress and anxiety. But whatever one thinks of the relative harm of false positives, this should not be confused or conflated with the harms of overdiagnosis and overtreatment.
The public has been sold a false bill of goods by mainstream cancer organizations, which for years have been pushing the simple story that annual mammography screening is the silver bullet to the breast cancer epidemic despite clear and mounting evidence to the contrary. Earlier this year, the Swiss Medical Board published a perspective in the New England Journal of Medicine saying boldly that mammography screening is “hard to justify”. The mantra “early detection saves lives” seems intuitive but is wrong, and annual screening seems like a good idea – except the evidence shows it just doesn’t do what we need it to. Indeed, the most striking feature of the ACS’s new recommendations is their acknowledgment that the balance does not clearly tip either for or against mammography screening for many women. Each woman must weigh the evidence and make her own decisions based on her known risk factors, values and preferences.
Unfortunately, the problem is the premise of “early detection” no matter what tool we’re talking about. Other screening modalities like tomosynthesis (or 3D mammography), ultrasound or MRI also bring the very same issues of false positives, false negatives, overdiagnosis, overtreatment, and cannot overcome the failures of current treatments to save lives. Early detection has not lived up to the promise: it has created a population of over-diagnosed breast cancer “survivors” without actually saving significantly more lives. We will never address and end the breast cancer epidemic simply through breast cancer screening, regardless of the screening tool; we need more effective, less toxic treatments that keep women from dying of breast cancer, and we need to prevent breast cancer from occurring in the first place.
While for some members of the public the new mammography screening guidelines released by the ACS feel like a sudden change, the truth is that for women’s health activists, the move is long overdue. Breast Cancer Action and others have long taken the ACS and other mainstream cancer organizations to task for failing to follow the evidence on routine breast cancer screening for women at average risk. To truly address and end the breast cancer epidemic, we must be willing to talk about the hard, controversial, for the most part deeply unpopular and not profitable truths of breast cancer screening.
Sadly, many women have been harmed by the sluggishness of the ACS and other large cancer charities to follow the evidence on routine breast cancer screening. While I welcome this first step by the American Cancer Society, I also mourn the fact that so many women have suffered from a cancer industry that wants to promote feel-good solutions rather than address the root causes and social injustices in breast cancer.
Just imagine where we would be today if the ACS had decided to act sooner and follow the evidence. Not only would tens of thousands of women been spared the physical, financial, and psychological harms of overzealous population-based screening, we might have used these resources more wisely to address the root causes of the disease, develop better individual risk assessment tools, eliminate the racial inequities in breast cancer outcomes, and ensured that all women have access to high-quality, affordable, evidence-based healthcare.