Why We Must Improve Breast Cancer Screening
By Dorraya El-Ashry, PhD | October 29, 2021
By Dorraya El-Ashry, PhD | October 29, 2021
Emerging trends during the pandemic reveal that the impact of delayed screenings will reverberate in the years to come. As we untangle the full impact of the pandemic on breast cancer, one thing is devastatingly certain: Delayed screenings will result in a rise of later-stage breast cancer diagnoses and still more preventable deaths. At the onset of the pandemic, diagnoses declined by over 50 percent. Norman Sharpless, MD, director of the U.S. National Cancer Institute, estimated there will be 10,000 excess deaths from breast and colorectal cancer in the decade ahead. Another study released in the Journal of the National Cancer Institute predicted that the overall number of excess deaths stemming from delayed screening, diagnosis and treatment would mean a 0.52% increase in breast cancer deaths between 2020 and 2030, or about 2,487 over the next decade. Deaths that may have been otherwise prevented.
These projections underscore the critical need for better screening technology and more personalized screening schedules. While mammography is the best tool we have today, researchers are developing and testing better, more accurate screening technology and more personalized, risk-based models for screening.
The standard screening tool used for breast cancer detection around the world is 2D mammography. In some imaging centers, a 3D mammogram with tomosynthesis (which is the use of low-dose x-rays), may be available to improve the performance of the technique. Additionally, about 40 percent of women over the age of 40 have dense breasts—a condition that requires additional screening with either whole breast ultrasound or MRI.
New research by Stephen Duffy, MSc in the journal Radiology underscores the lifesaving value of screening. Women who went in for two of their most recent mammography screening appointments before a breast cancer diagnosis were 50 percent less likely to die. For women who went in for only one screening, that number dropped to 30 percent. This suggests that missing even just one screening appointment can have serious consequences.
Most cancer centers across the U.S. recommend screening should start annually at the age of 40, while the U.S. Preventative Task Force recommends that women start at the age of 50, every other year. Why the disconnect? Recommendations to start at 40 stems from research that early detection is key to survival. While recommendations to start later at 50 aims to reduce the rate of false positives that result in unnecessary biopsies and testing. Both are valid concerns yet hugely problematic because a one-size-fits-all approach to screening recommendations creates vulnerable populations. For example, women 25-39 with no family history are entirely unscreened and yet younger women have had a significant increase in late-stage breast cancer diagnoses over the last few years. Additionally Black women are more likely to be diagnosed at younger ages with more aggressive cancers. What we’re learning now is that personalized, risk-based screening should be the ultimate goal. Research can help us better identify and even quantify that risk, better informing decisions around screening.
We need to do better for patients by investing in better tools. It is an undeniable fact: Early detection saves lives. When caught early, breast cancer has nearly a 100 percent rate of 5-year survival. But at later stages, survival rates drop precipitously—and there are no cures for metastatic/stage 4 breast cancer, yet. The estimated number of American women living with metastatic breast cancer rose to 168,000 this year from 150,000 last year. These numbers don’t account for the pandemic’s influence on breast cancer, which is already projected to be significant.
We must also keep in mind existing racial disparities that stand to widen as a result: Black women are 40 percent more likely to die from breast cancer than white women despite the fact that these two groups are diagnosed at similar rates. Black women are more likely to be diagnosed with more aggressive, fast-growing forms of the disease, at younger ages—ages that are less likely to be screened—and at more advanced stages. Any decline in screening for Black women in particular could have devastating effects on increased deaths and further exacerbate the existing and patently unacceptable disparities in outcomes.
And finally, we need to take into account data emerging on breast cancer in younger women—women who aren’t screened. While breast cancer in women under 40 still has a 5-6% incidence, two recent findings point to the need for improved, more precise and risk-based screening guidelines. First, the decrease in breast cancer mortality—40 percent in the last 30 years—has slowed in rate of decline over the past several years, and this year, for women under 40 it has stopped. Second, as mentioned earlier, a recent study indicates that late-stage diagnoses have increased significantly in younger women. The authors discuss the lack of screening in this group of women as one potential reason.
We can’t stand still. While the tools at hand today undeniably save lives, they are also in critical need of improvement. New technology like artificial intelligence and contrast-enhanced spectral mammography show incredible promise to provide more accurate results—reducing false positives, unnecessary procedures (and the resulting stress), while simultaneously improving the accuracy of otherwise missed diagnoses.
The potential for deep-learning models to identify the right patients for additional or frequent testing is revealing itself more and more–moving us closer to risk-based screening. And we are still learning about the complex interplay of genetics and lifestyle factors that increase risk: The first large, multi-center study to examine genetic mutations in women with no family history was published early this year.
Even as prevention becomes more precise, it requires committed investment.
All signs point to an increase in preventable deaths from breast cancer in the years to come. It is critical that women return to screening and encourage their loved ones to do the same. Simultaneously, research that advances lifesaving technology and personalizes screening are key imperatives, highlighted in stark contrast over this past year. We know that early diagnosis is a key determinant of survival and improving screening technology will undoubtedly save lives.
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