We have been interested in the quiz series focused on breast cancer screening for women with dense breasts presented in OBG Management by DenseBreast-Info.org. However, we have concerns with the answer as presented in the December 2021 issue, “Average-risk women with dense breasts—What breast screening is appropriate?” (OBG Manag. 2021;33(12):18-19. doi: 10.12788/obgm.0155.) The main question asks about appropriate imaging beyond mammography/tomosynthesis for women with extremely dense breasts and no other risk factors for breast cancer. The authors recommend magnetic resonance imaging (MRI), ultrasonography, or contrast-enhanced mammography (if MRI is not an option). This advice, however, does not follow current guidelines from the American College of Obstetricians and Gynecologists (ACOG) and other professional organizations. We can certainly understand that an advocacy group would want ObGyns to be proactive about adjunctive imaging in average-risk women with heterogeneously dense or extremely dense breasts. However, at this point in time, there are no clear data to support a recommendation for adding universal MRI in this population, for many reasons that we will discuss herein.
The concerns with breast cancer in particular
Breast cancer is not cervical cancer. It isn’t one disease. It is a multitude of diseases that happen to show up in the breast. Some are relatively slow-growing—the kinds of cancers that lend themselves to screening and to early intervention. But other cancers are rapidly-growing; they show up no matter how often or what modality we use for screening. Our goal should be to find an approach to screening that can diagnose breast cancer at a stage where we can intervene and positively impact breast cancer specific and overall mortality.
Screening guidelines vary
The variety of screening guidelines published by different professional organizations reflect differing assumptions and sets of values related to the early diagnosis and treatment of breast cancer. (For a comprehensive table of current screening guidelines, see https://www.cdc.gov/cancer/breast/pdf/breast-cancer-screening-guidelines-508.pdf.)
ACOG’s approach—to offer screening at age 40 but to begin by at least age 50 and, through shared decision making with the patient, screen every 1 or 2 years—is focused on capturing as many cases as we can identify, while minimizing the harms of false-positives.1 The perspective of the US Preventive Services Task Force (USPSTF) recommendations (to screen every 2 years beginning at age 50) is at the population level, a cost-effective approach that will have the greatest benefit while minimizing harms in the population at large.2 The American Society of Breast Surgeons recommends screening to begin by age 40.3 Like the breast surgeons, radiologists dedicated to breast imaging are focused on an individual rather than a population level. They strive to identify each and every instance of possible cancer, and therefore recommend annual screening beginning at age 40.4 However, with more aggressive screening in average-risk women many cases of ductal carcinoma in situ (DCIS) are identified—a lesion that, if not detected, may not impact the woman’s health during her lifetime—representing what some might call “overdiagnosis.” Yet there may be some instances in which the DCIS might affect an individual woman’s health. Unfortunately, we can’t prospectively distinguish between the first and the second types of cases.
Screening approaches reflect guidelines and individual values
We follow American College of Obstetricians and Gynecologists and US Preventive Services Task Force guidelines in discussing screening (both its hazards and benefits) with our average-risk patients beginning at age 40. We talk about risk factors for breast cancer, including breast density, but let patients know that no specific additional imaging is advised, and that density is more common in younger women (one consideration in earlier screening) and is quite common in general. Although we do not send follow-up letters to patients with dense breasts, we do educate our staff so that they can respond appropriately should patients call with questions.
Of course, we all bring to the table values that will impact the decisions that we make for ourselves and for our patients. What an ObGyn might suggest may differ from what a radiologist might suggest. Although we follow recommendations made by the radiologist at screening, an ObGyn wants to take care of the whole human being. We are concerned with bones, heart, everything about the patient, so we approach a patient in a different way. These priorities are reflected in the current varying breast cancer screening guidelines.
Continue to: Research on breast cancer screening varies by design...