Controversies in Breast Cancer Screening
As October comes to a close, so too does Breast Cancer Awareness Month – 31 days devoted to raising public awareness and funding to combat one of America’s most dreaded diseases. Most Americans have a close friend or family member who has battled breast cancer. Angelina Jolie is quoted in her 2013 Op-Ed piece for the New York Times as saying that the word cancer “strikes fear into people’s hearts, producing a deep sense of powerlessness.” For those with experience with this disease, these words ring very true.
According to the American Cancer Society, an estimated 231,000 women will be diagnosed with invasive breast cancer in 2015, and an additional 60,000 will be diagnosed with early, non-invasive disease (carcinoma in situ). Forty thousand will die from breast cancer. Breast cancer is the second leading cause of cancer death for American women. Fortunately, breast cancer deaths have declined in the past 15 years, likely due to improved treatment, increased awareness, and early detection.
The Pink Movement
While few can deny the importance of breast cancer awareness, critics of the “pink movement” do exist. Some argue that efforts should be directed at campaigns for healthier lifestyles to prevent breast cancer. Others criticize that companies exploit Breast Cancer Awareness Month to promote their products, when in fact their products may be unhealthy and increase breast cancer risk.
Critics of breast cancer screening programs also exist, and mammography guidelines have been hotly debated in recent years. Historically, mammography has been the gold standard for the detection of abnormal breast lesions. Current guidelines differ between groups, but most American medical associations are in favor of routine mammography as first line screening for women who are not at high risk for breast cancer.
The United States Preventive Services Task Force (USPSTF), is an independent consortium of national experts in preventive medicine that publishes evidence-based guidelines on screening and prevention measures in order to improve the health of our country. Currently, the USPSTF is revising its breast cancer screening guidelines. A draft of updated guidelines recommends biennial (every 2 years) mammography for women ages 50-74 years. For women ages 40-49, the USPSTF suggests that the decision to start screening should be an individual one, because the risk of breast cancer death in this age group is lower than in older women. The American College of Physicians agrees that screening mammography decisions for women between 40-49 should be individualized based on a woman’s preference and risk factors. In contrast, the American Congress of Obstetricians and Gynecologists (ACOG), one of the most widely respected organizations in women’s health in the US, recommend yearly mammography starting at age 40, as does the American Cancer Society and the American College of Radiology and the Society for Breast Imaging. These differing recommendations are confusing for patients and healthcare providers alike.
Critics of breast cancer screening programs have begun to publish their opinions and data in respected medical journals, and have been met with harsh pushback. An independent, nationally appointed medical board in Switzerland recently announced their position that mammography should be stopped because its harms outweigh its benefits. In September of this year, a Danish physician from a highly respected European research team boldly stated that “mammography is harmful and should be eliminated” and that “if screening had been a drug, it would have been withdrawn from the market long ago.”
So what are the roots of such controversy? A look at the risks and benefits of mammography may help to shed light on this complicated and important debate.
Benefits of Mammography
Evidence suggests that screening mammography does decrease breast cancer mortality, (the number of women who die from the disease). Randomized trials have found an estimated 20% reduction in breast cancer mortality when comparing women who have undergone routine screening mammography to those who have not. Gotzsche argues that such statistics are based on old studies that were done prior to the advances in breast cancer treatments that we have currently and suggests that studies done today would further decrease any reduction in mortality from routine mammography.
Early detection of breast cancers is associated with much higher survival rates, and mammography is a relatively low-cost tool for structural breast assessment and evaluation compared to other imaging tests, and can often detect small tumors at early stages.
In the developing world, mammography is widely available in hospitals, radiology centers, and even on mobile vans. Improving access to mammography for underserved women is a priority of many public health initiatives because some underserved groups such as African American women are at increased risk for breast cancer death compared to other ethnic groups.
Harms of Mammography
Despite its benefits, mammography carries certain risks. The most important risk of routine mammography in low risk women is “overdiagnosis”, or the diagnosis and treatment of disease which, if left alone, would not have been a threat to a woman’s health. Studies suggest that 20-30% of breast cancers are overdiagnosed and up to half of noninvasive carcinomas in situ may have resolved without any intervention. Because it is not possible to determine which noninvasive cancer will progress to advanced disease, the current standard of care is to treat these cancers as if they were going to progress. Treatment may include lumpectomy, mastectomy, radiation therapy, or hormone therapy, all of which carry inherent risks.
False positive findings are another potential “harm” of mammography. Many women receive news of an abnormal finding on a routine mammogram and undergo additional imaging, or perhaps a biopsy, to rule out cancer. More often than not, these findings are benign, but the weeks to months of waiting and wondering while tests are being run can have a harmful impact on the psychological wellbeing of a woman and her family. After 10 mammograms, the risk of receiving a false positive result is between 20-60%.
Similarly, false negative results may occur as a result of mammography. This means that a woman is told that her mammogram is “normal” when in fact a small cancer has been missed. This may provide a false sense of security and contribute to continuation of behaviors that increase the risk for breast cancer such as unhealthy eating habits, smoking, and lack of exercise.
Many women are concerned about radiation exposure from regular mammography. We are exposed to background radiation on a daily basis just from living and interacting on earth. One bilateral mammogram with 2 views of each breast delivers a radiation dose equivalent to that of 7 weeks of normal daily living exposure. For some women, this dose seems small and insignificant. For others, it is beyond their comfort level and undesired, especially when added up over 2-3 decades of screening. Radiation-induced breast cancers do exist and the contribution of radiation from mammography is unclear.
For Gotzche, the culmination of these risks poses a threat to women’s health which outweighs any benefit that mammography might provide. A mammography leaflet describing his findings and recommendations is available at www.cochrane.dk. H. Gilbert Welch, a Dartmouth physician and researcher shares many of Gotzche’s views about mammography and has written about them in his book “Overdiagnosed: Making People Sick in the Pursuit of Health.”
So where do we go from here? Alternatives and complements to mammography do exist, although few have been studied thoroughly enough to enable recommendations for routine use.
Alternatives to Mammography
3-D mammography, or tomosynthesis, takes a three-dimensional picture of the breast (traditional mammography is 2-D) which allows for greater detail and accuracy. 3-D mammography may identify lesions that would have been missed with traditional mammograms alone, thus reducing the risk of false negatives. Currently 3-D mammography is available at various health centers in CT and is done alongside traditional mammograms.
Breast thermography, or digital infrared imaging, is based on the concept that heat is produced from increased circulation and metabolic changes associated with tumor growth. Thermography may detect thermal signs of early changes that are too small to be found on mammograms or even MRIs. For now, thermography is being used as a complement to mammography and private thermography centers exist in Connecticut.
Experimental breast imaging tests are being researched, and include optical imaging tests, molecular breast imaging, and positron emission mammography.
Clearly, the mammogram debate is complicated. There is no doubt that further studies are needed in order to find the best screening tool for breast cancer. In the meantime, routine mammography will remain the gold standard for early detection of breast cancers in the United States. Being an informed healthcare consumer is a powerful tool. Discussing current guidelines and controversies with your healthcare provider can help you to make the best decision possible for your health, given your unique history. In addition, it can strengthen the patient-provider relationship to form a more unified team working together to solve life’s health challenges.
APRN Amanda Swan is a general practitioner at ProNatural Physicians Group. ProNatural is an integrated group of practitioners including naturopathic doctors and acupuncturists, APRNs and massage therapists. The practice is growing to include more medical modalities and to offer more family treatment options including vaccinations.
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