Breast cancer is a common and still lethal disease in the United States. More than 230,000 are likely to be diagnosed with breast cancer this year and it is expected to claim more than 40,000 lives. Early detection of breast cancer saves lives and can minimize treatment.
Earlier this year, Breastlink responded to updated U.S. Preventive Services Task Force (USPSTF) recommendations to delay screening mammography until age 50 by emphatically detailing the potential harms of delaying a cancer diagnosis. These harms include increased toxicity of chemotherapy, more extensive surgery and a higher risk of lymphedema, as well as the emotional and financial burden of treatment. Once again, research confirms that annual screening with mammography starting at age 40 saves the most lives.,
Revised ACS Guidelines for Breast Cancer Screening
Recently, the American Cancer Society (ACS) has issued new breast cancer screening recommendations that have caused much discussion. In 2003, ACS recommended annual screening mammography and clinical breast exam (CBE) for all women starting at age 40. Now, in 2015, they have adjusted their recommendations after an updated systematic literature review. These recommendations are perplexing and, for some, problematic.
The current ACS guidelines recommend the following for AVERAGE risk women:
- Begin annual screening mammography at age 45.
- Continue annual screening from 45 to 54.
- Reduce screening intervals to once every 2 years beginning at 55.
- Continue biennial screening for as long as life expectancy is 10 years or more.
- Women aged 40 to 44 and older than 55 should have the opportunity to receive annual screening.
- CBE is not recommended in women at average risk.
The ACS guidelines emphasize the potential harms of “false positives” – or a mammographic or clinical finding leading to a benign biopsy. False positives are highest in women ages 40 to 49.
It is important to note that, similar to data used in the flawed USPSTF recommendations, data used for the ACS guidelines was derived from studies predominantly using film mammography. This ignores the benefits of digital mammography and, now, the even more superior 3D mammography, or tomosynthesis, which is currently in use.
Improved Technology Increases Cancer Detection & Reduces False Positives
There is ample evidence to show that tomosynthesis can decrease recall rates and thereby minimize the potential harms of screening. In a study of more than 450,000 patients, 3D mammography offered a 15% decrease in recall rates and a 41% increase in cancer detection compared with conventional 2D mammography. Two additional studies showed a 30% to 37% decrease in recalls with 3D mammography.,
More importantly, the ACS guidelines are specifically meant for an average risk woman. In their report, average risk is loosely defined. Its definition excludes women with prior breast cancer diagnoses, women with breast cancer-related genetic mutations, and women with a history of radiation to the chest wall radiation.
This definition of risk is inadequate. There are clearly women who fall into intermediate- and high-risk categories who should approach screening from different screening algorithm.
Before any woman should be defined as having “average risk,” a thorough risk assessment should be performed to individualize and personalize screening recommendations. ACS and USPSTF make population-based recommendations, which does not consider individual concerns, history and issues. At the same time, both sets of guidelines recommend that patients discuss their concerns with their physicians. At the end of the day, the onus is on the physician to provide the best care for their patients.
While we can easily say annual screening starting at age 40 is acceptable, mammography alone will not be sufficient for some patients. Risk assessment involves taking a thorough personal and family history, incorporating the following issues:
- Previous breast biopsy and presence of atypia or lobular carcinoma in situ.
- Age at menarche, or age at first menstrual cycle.
- Age at menopause.
- Nulliparity, or age at first childbirth.
- First-, second-, and third-degree relatives with breast, ovarian and other cancer history on both maternal and paternal sides of the family.
- Body mass index.
- Combination hormone therapy use and duration.
Once this history is obtained, there are numerous risk calculators that can estimate a woman’s lifetime risk of developing breast cancer, such as the Gail Model or the Tyrer-Cuzick model. Low risk, or “average” risk, is defined as having a lifetime risk less than 15%, intermediate is 15% to 19%, and high risk is greater than 20%.
In addition to evaluating lifetime risk, women and their physicians must consider breast density. Women with extremely dense breasts have an approximate 4-fold increased risk of developing breast cancer compared to women with fatty breast parenchyma. Many states now have laws mandating discussion about breast density as part of routine counseling for women undergoing screening mammography.
In women with dense breasts, screening mammography should occur annually AND may also need to be paired with other exams. Supplemental screening options include 3D mammography, automated whole breast ultrasound (ABUS) and breast MRI.
- For women with low/average lifetime risk and dense breasts, we recommend annual MMG with either 2D or preferably 3D-MMG.
- For women with intermediate lifetime risk and dense breasts, we recommend annual MMG as well as whole breast screening ultrasound.
- For women with high lifetime risk (especially those with dense breasts), we recommend annual MMG as well as screening MRI.
Clinical Breast Exam
Lastly, the ACS guidelines recommend discontinuation of routine CBE in average risk women. ACS states that there is a lack of evidence showing benefit to CBE. However, a lack of evidence does not mean there is no benefit to CBE.
We regularly, on a weekly basis, see patients who have been diagnosed following CBE or self-breast exam. Some cancers, such as lobular breast cancers, can be difficult to detect on mammography. Others, like high-grade, triple-negative cancers, can grow quickly within months of a normal mammogram. CBE plays an important role in breast health for all women, but is especially important in women who DO NOT receive annual screening mammography.
Promoting Thoughtfulness in Breast Cancer Screening Recommendations
It is clear that the ACS has issued these new guidelines in a way to help decrease “overdiagnosis” and the “harms” associated with false-positives. However, technology is constantly improving. Digital mammography and 3D mammography have helped to decrease these harms.
The other issue of overdiagnosis is still important. For some women, the cancers we find will not ever become lethal. Rather than encouraging fear of a potential problem, the medical community needs to do a better job of determining which patients can benefit from different types of treatments.
Fortunately, we are making strides to overcome the problem of overtreatment. At Breastlink, we are involved in a clinical trial investigating Cryoablation. This treatment can be used to avoid surgery and treat older women with small cancers. Additionally, a national trial evaluating a non-surgical option for stage 0 breast cancer, ductal carcinoma in situ, is set to begin soon.
Together, with advancements in research and technology, we can overcome the issues of overtreatment and minimize harms without denying women access to or scaring them from screening mammography.
Rebecca L. Siegel et al. “Cancer Statistics, 2015.” CA: A Journal for Cancer Clinicians. January/February 2015.
Daniel B. Kopans. “Arguments Against Mammography Screening Continue to be Based on Faulty Science.” The Oncologist. February 2014.
R. Edward Hendrick et al. “Benefit of Screening Mammography in Women Aged 40-49: A New Meta-Analysis of Randomized Controlled Trials.” Journal of the National Cancer Institute. January 1997.
 Kevin C. Oeffinger eta al. “Breast Cancer Screening for Women at Average Risk: 2015 Guideline Update from the American Cancer Society.” Journal of the American Medical Association. October 2015.
Sarah M. Friedewald et al. “Breast Cancer Screening Using Tomosynthesis in Combination with Digital Mammography.” Journal of the American Medical Association. June 2014.
Stephen L. Rose et al. “Implementation of Breast Tomosynthesis in a Routine Screening Practice: An Observational Study.” American Journal of Roentgenology. June 2013.
Brian M. Haas et al. “Comparison of Tomosynthesis Plus Digital Mammography and Digital Mammography Alone for Breast Cancer Screening.” Radiology. December 2013.