Meaningful progress has been made in reducing deaths due to breast cancer over the last half century, with a 43% decrease in mortality rate (breast cancer deaths per 100,000 population).1 Screening mammography (SM) has contributed greatly to that success, accounting for 30% to 70% of the reduced mortality rate, with the remainder due to advancements in breast cancer treatment.2 Despite these improvements, invasive breast cancer remains the highest incident cancer in the United States and in the world, is the second leading cause of cancer death in the United States, and results in more years of life lost than any other cancer (TABLE 1).1,3
While the benefits and harms of SM are reasonably well understood, different guidelines groups have approached the relative value of the risks and benefits differently, which has led to challenges in implementation of shared decision making, particularly around the age to initiate routine screening.4-6 In this article, we will focus on the data behind the controversy, current gaps in knowledge, challenges related to breast density and screening in diverse groups, and emerging technologies to address these gaps and provide a construct for appropriate counseling of the patient across the risk spectrum.
New series on cancer screening
In recognition of 35 years of publication of OBG Management, this article on breast cancer screening by Mark D. Pearlman, MD, kicks off a series that focuses on various cancer screening modalities and expert recommendations.
Stay tuned for articles on the future of cervical cancer screening and genetic testing for cancer risk beyond BRCA testing.
We look forward to continuing OBG Management’s mission of enhancing the quality of reproductive health care and the professional development of ObGyns and all women’s health care clinicians.
Breast cancer risk
Variables that affect risk
While female sex and older age are the 2 greatest risks for the development of breast cancer, many other factors can either increase or decrease breast cancer risk in a person’s lifetime. The importance of identifying risk factors is 3-fold:
- to perform risk assessment to determine if individuals would benefit from average-risk versus high-risk breast cancer surveillance
- to identify persons who might benefit from BRCA genetic counseling and screening, risk reduction medications or procedures, and
- to allow patients to determine whether any modification in their lifestyle or reproductive choices would make sense to them to reduce their future breast cancer risk.
Most of these risk variables are largely inalterable (for example, family history of breast cancer, carriage of genetic pathogenic variants such as BRCA1 and BRCA2, age of menarche and menopause), but some are potentially modifiable, such as parity, age at first birth, lactation and duration, and dietary factors, among others. TABLE 2 lists common breast cancer risk factors.
Breast cancer risk assessment
Several validated tools have been developed to estimate a person’s breast cancer risk (TABLE 3). These tools combine known risk factors and, depending on the specific tool, can provide estimates of 5-year, 10-year, or lifetime risk of breast cancer. Patients at highest risk can benefit from earlier screening, supplemental screening with breast magnetic resonance imaging (MRI), or risk reduction (see the section, “High-risk screening”). Ideally, a risk assessment should be done by age 30 so that patients at high risk can be identified for earlier or more intensive screening and for possible genetic testing in those at risk for carriage of the BRCA or other breast cancer gene pathogenic variants.5,7
Continue to: Breast cancer screening: Efficacy and harms...