SABCS 2020: Why Mammograms Can’t Fix Breast Cancer Disparities

By Jayla Burton, Program Officer

The growing attention to breast cancer disparities for Black women has resulted in an increase in marketing campaigns targeting women of color telling us that we must get screened for breast cancer. For many people, at first this sounds like good advice, especially considering Black women are more likely to be diagnosed at a younger age and at a later stage and have more aggressive forms of the disease. Shockingly, Black women are 40% more likely to die from breast cancer than white women—and we learned at this year’s San Antonio Breast Cancer Symposium (SABCS) that Black women experience even worse breast cancer mortality ratios (over 60%) in states like Louisiana, Mississippi, Wisconsin, and New Mexico!

These statistics are deeply alarming. For me, they are also unendingly frustrating because I know there are no simple solutions. Like many people, at one time I was under the impression that mammography screening was a one-way road to better breast cancer outcomes. Breast Cancer Action has challenged my thinking, drawing me to take a more rigorous look at the data that addresses the serious disparities in breast cancer for Black women and other people of color. I can say confidently that I no longer believe the oversimplified mantras of breast cancer screening. Unfortunately, evidence shows more women are harmed by screening than benefit from it; women are more likely to experience overtreatment than have their lives saved.

Given my understanding of the limitations of screening and how harms may contribute to and exacerbate inequities for Black and Brown folx, the session about global breast cancer screening caught my attention, specifically the presentation titled “Weighing the benefits and harms of breast cancer screening” by Philippe Autier MD, PhD from the International Prevention Research Institute.

Too often, there is a one-sided presentation of benefits of breast cancer screening. This results in women being more likely to be familiar with the perceived benefit, or the perception of the positive consequences, of mammography screening rather than the harms. We can acknowledge that there are some benefits to screening without over exaggeration. For example, finding smaller cancers sometimes gives the option of less aggressive breast cancer surgeries, such as lumpectomy rather than mastectomy. But every medical procedure can also cause harm, and too often the harms of screening are left out of the discussion.

When listening to Dr. Autier’s presentation there seemed to me that there were two problems at play. One, detecting cancer has been the primary measure for determining if screening is effective. While there’s no question mammograms detect cancer, often these are not life threatening. This is why we must remember that the real goal of screening is to prevent death, from any cause. And two, screening has been positioned as the primary solution for addressing disparities. However, screening results in overdiagnosis, overtreatment, burdensome economic costs, decreased quality of life, as well as false positives and false negatives which may themselves produce and widen breast cancer disparities.

In his review of the existing evidence, Autier pointed out that in most countries, including the United States, mammography has led to a very small decrease in the incidence rate of advanced breast cancer. However, we would expect that if mammograms caught more early stage breast cancers, there would be a much greater reduction in late stage cancers. Disappointingly, the evidence does not support the claim that screening reduces breast cancer mortality.

But it’s not just a smaller than expected benefit, there are also harms to consider.

Overdiagnosis is “the detection of slow or non-growing cancers and the diagnosis of cancers that would not have existed in the absence of screening, and that would not have been clinical during a woman’s life time.” The consequence of overdiagnosis is overtreatment, or the treatment of cancer that would have never produced symptoms or become life-threatening. Treatments can bring a wide range of harms, including chronic pain and discomfort, heart disease from radiation, and financial toxicity.  

Dr. Autier showed that randomized trials in both Europe and the U.S. have sought to quantify the benefits and harms of routine screening, in order to support more informed decision making. In Europe, for every 1,000 women screened for breast cancer every two years starting at the age of 50 there would be 200 false positives—that is a shocking one in five women!—and this results in 30 unnecessary biopsies—or around one in 30 women. Most importantly, 15 cancers would be overdiagnosed, meaning these women would experience the harms of treatment for a cancer that is not and never would be life threatening (Loberg et al, 2015). In the United States, where aggressive treatment is the norm, the numbers are even more sobering. For every 1,000 women screened every two years starting at the age of 50, there would be 880-1210 false positives, 130-170 unnecessary biopsies, and 9-34 overdiagnoses (Welch & Passow, 2014).

The goal of routine screening is to prevent death. For breast cancer-specific mortality, there is small reduction in deaths for women who are screened. However, if we look at overall survival (OS, or mortality from any cause), we don’t see the same reduction in mortality. Since mortality rates are the same in both screened and unscreened populations, we must ask how it helps to trade breast cancer-specific deaths for deaths from another cause.

Dr. Autier acknowledged that the mammography and screening debate is the Pandora’s Box of breast cancer. The data presented by Autier is not new but he suggests ways to reduce the harms of breast cancer screening. These suggestions include:

  1. Do fewer screenings. There is no evidence that increased rounds of screening are more effective than less.
  2. Avoid MRI screenings as a solution. MRI screenings results in increased mastectomies without evidence of reducing breast cancer mortality. Autier found that 667 women would need to be screened to prevent one breast cancer death, affirming that other screening modalities, such as MRIs, can have the same benefit-to-harm ratio.
  3. Identify new tools. Instead of turning to other screening modalities as a solution, such as ultrasounds and MRIs, which raise the same issues as mammograms, the focus should be on improving screening protocols to better identify who will actually benefit from screening so that fewer women are harmed.

Breast Cancer Action believes all women should have access to balanced, evidenced-based information. It is evident that looking at the benefits of screening also means weighing the harms, yet Black women are told to get mammograms, with no evidence it will save lives or eliminate disparities. This is one case where equal treatment is not equitable treatment, because limited access to treatments, the wrong treatments, and overtreatments are each unique forms of healthcare disparities. But where is the discussion of the harm of overtreatment and the ways that unnecessary treatment is itself a health justice issue? Despite growing rates for Black women getting screened, mortality rate has not been reduced. In fact, harms from overdiagnosis and overtreatment can be amplified by comorbidities that are more common for Black women including heart disease, diabetes, obesity coupled with potential stress, disruption of healthcare, and financial burdens brought about by COVID-19.

Unfortunately, focusing solely on screening will not address the gaping breast cancer disparities, and may lead to new inequities associated with overtreatment and other harms of screening. Meanwhile, we would do well to pay attention to the fact that Black and Brown communities live and work in built environments that disproportionately expose us to toxins that increase the risk of breast cancer. These communities have limited access to quality healthcare, and combined with longstanding structural racism—both within and outside of the medical system—leads to negative health outcomes for BIPOC communities. 

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