While most women readily undergo regular breast squooshing mammography radiation to screen for breast cancer, there are many misunderstandings about, and much we simply don’t know about the widely accepted test. In The Big Squeeze: A Social and Political History of the Controversial Mammogram, Handel Reynolds, MD provides a riveting look at the history of mammography that gives us a better understanding of what we do and don’t know about breast cancer screening.
The story of mammography is part science and medicine, but also in large part cultural, political and economic. At the beginning of his narrative, Dr Reynolds notes that,
As mammography was aggressively promoted int he 1980s to 1990s, utilization rates rapidly increased. As this occurred, the mundane mammogram became the little pink engine that could, and did, drive the growth of a vast screening-dependent secondary economy.
For many years, women in the U.S. were told to begin annual screening at age 40. In the last few years however there have been numerous reports that come to different conclusions about how often to screen and at what age to start screening. But it is not widely known that this is hardly a new uncertainty. The results of the first large study of mammography’s effectiveness, the HIP (Health Insurance Plan of Greater New York) which began in 1963 did not support beginning annual screening at age 40, and according to Dr. Reynolds,
It is important to note that the benefits of screening were seen only in women fifty to fifty-nine years old. No benefit was demonstrated for women sixty to sixty-nine or forty to forty-nine.
While most of us are all too aware that there are many more cases of breast cancer than there were 50 years ago, what we fail to understand is that a significant part of that increase is due not to actual new cases, but that we are finding them. In fact the first nationwide screening demonstration program, the Breast Cancer Detection Demonstration Project (BCDDP), which began in 1973 led to a 14% increase in the known incidence of breast cancer in 1974-75, according to Dr. Reynolds.
Concerns about radiation exposure from mammography are also nothing new. As early as 1976, Dr. John Bailar III of the National Cancer Institute (NCI) raised concerns about the risks of radiation-induced breast cancer from mammography which led to warnings about those risks being given to women considering screening and the NCI issued guidelines that said they could not recommend routine screening for women between the ages of 35-49.
But as Dr. Reynolds points out, radiologists have been heavily involved with the American Cancer Society (ACS) and 6 presidents of ACS have been radiologists. Hardly surprising then that it was ACS that began to make assertions that up to 80% of women in the 35-49 year old age group fell into one or more high risk categories and therefore should be screened.
Dr. Reynolds also writes that the BCDDP study did not have a control group that did not undergo screening, and because of that, it could not answer the question of whether or not screening resulted in less deaths (which is the usual standard of whether such screening is effective). That however did not stop ACS from inferring that because the earlier HIP study indicated a mortality reduction in women over 50, it was also reasonable to assume that with improving mammography equipment, younger women would benefit as well and
In 1976…(ACS) adopted a position that women forty to forty-nine years old should be screened every one to three years. At the time, it offered no scientific justification for this recommendation. There was none. (emphasis mine)
Dr. Reynolds analysis of how mammography became widely accepted is quite enlightening. He points to the blatant use of fear as a tool to convince women to get screened in the late 1980s with the American Cancer Society leading the way in telling us that breast cancer rates were rapidly rising despite the fact that the increased numbers of cases were attributable in part to increased use of screening (as well as by women’s longer life expectancy–you are more likely to die of breast cancer if something else hasn’t killed you at an earlier age). It wasn’t that the cancer wasn’t there before, it was that we weren’t aware of it or died of something else first.
ACS mounted a huge campaign around the use of the statistic that one in nine women would get breast cancer. Yet an ACS spokesperson was quoted in the New York Times as saying that it was, “meant to be a jolt…It’s meant to be more of a metaphor more than a hard figure.” (emphasis mine).
As Dr. Reynolds notes, that sort of messaging led to women overestimating their own risk of getting breast cancer as well as overestimating the benefits of mammography and the all too common mis-perception that regular screening can keep you from getting breast cancer.
The book goes on to cover later studies that really brought into question whether there was any benefit to routine screening before the age of 50 and the very real risks of over-diagnosis and treatment for cancers that might not be life-threatening and to what extent screening really decreases fatalities as well as the problems of false negatives and false positives in mammography. Towards the end of the book Dr. Reynolds takes a look at the problem of DCIS which in some cases would never be fatal but because we don’t know which cases might or might not become invasive, all cases are usually treated. Dr. Reynolds suggests that we need to re-evaluate that approach because it puts so many women at risk for the complications of unnecessary treatment, suggesting that regular re-evaluation of such cases rather than immediate treatment may be appropriate.
This book is both fascinating and quite readable, and highly recommended. It tells a necessary part of medical history that is much, much too relevant to anyone facing this disease or who knows someone who is (in other words, all of us). That said, at the end of the book, Dr. Reynold tells us that we simply don’t know how much the recent drop in breast cancer deaths is due to screening and how much is due to better treatments. Nor does he mention environmental factors or the role that the decreased use of hormone therapy may make in these rates. Despite that, he asserts that,
Screening benefits women aged forty to forty-nine and those who are fifty and older. The magnitude of the benefit however is greater for those over fifty. With the battle for access essentially having been won, I believe that mammography should and will continue to be available to all women over forty who wish to be screened.
It is also necessary to note that for poor women and women without insurance, mammograms have not necessarily been available. While I agree with Dr. Reynolds that mammograms should be available to any woman who wants to be screened, the data is far from clear as to just how beneficial non-diagnostic screening is.
A few additional thoughts:
1. Concerns about the harms of radiation from mammography are as valid today as they were when they were first raised. Particularly in light of the concerns raised by scientists at the FDA about excessive radiation from GE mammography machines.
2. This chart showing global breast cancer mortality rates is illuminating. The U.S. has lower rates than Canada and some European countries yet higher rates than some South American countries and Australia. While I’ve only been able to gather screening recommendations from English speaking countries, it is worth noting that both Canada and Australia recommend far less screening than is the norm in the U.S., yet one of them has a higher mortality rate than we do and one is roughly the same, leading me to truly wonder how we can say that routine screening is effective. See this map as well.
3. According to The Telegraph (UK), the recent drop in breast cancer mortality in Europe is due primarily to treatment, not screening, a conclusion drawn because the drop applies to women under 50 as well even though most European countries do not have regular screening programs for younger women,
Professor Carlo La Vecchia, one of the study leaders from the University of Milan, said: “The fact that there will be substantial falls in deaths from breast cancer, not only in middle age, but also in the young, indicates that important advancements in treatment and management are playing a major role in the decline in death rates, rather than mammographic screening, which is usually restricted to women aged 50 to 70 in most European countries.
4. According to a 2011 Health Day article that looked at the relationship between screening and breast cancer death rates in several European countries, it is not clear whether recent drops in death rates are attributable to screening or to better treatments. A WHO study found that the rates were similar regardless of screening.
5. You may also want to listen to Uprising Radio’s Sonali Kolhatkar’s interview with Dr. Reynolds here.
What are we to make of all this? Dr. Reynolds’ book provides some valuable historic context to our understanding and decision-making about mammography. What I think is abundantly clear (and as Dr. Reynolds points out) is that policies about mammography have been the result of a far from perfect mix of science, medicine, emotion, politics and economic considerations.
It is beyond unfortunate that we need to be skeptical when it is radiologists who push mass screening–on the one hand it is their area of expertise. On the other, we live in a country where medicine is a for profit business and it is in their best interest to recommend their own procedures. And as the recent Komen for the Cure dustup reminded us, there has been a real price paid for focusing on “curing” cancer rather than finding its cause and the enormous profitability of treating cancer has been one of the reasons. That has to change because the real truth is that cancer cannot be cured, only treated, and what we need to do is focus on cause and prevention. Until then, too many of us will keep dying of this disease.