Certain risk factors warrant breast cancer screening at age 30

Robert Smith, PhD

There is no question that in an era of personalized medicine we want to avoid missing an opportunity to identify who may be at a higher risk for breast cancer before the age of 40, but this abstract by Lee and colleagues does not say how many women with risk factors for breast cancer had normal examinations, and how many women with the abnormal examinations went onto be diagnosed with breast cancer. We also don’t know anything about the family histories (ie, age at diagnosis of the affected first-degree relative, whether the family histories were first- or second-degree relatives, or if any of these women had more than one affected relative, and we don’t know if any of them already had been tested and were positive for a mutation on a breast cancer susceptibility gene).

Risk for breast cancer is heterogeneous, so it is not surprising that women in their thirties with one of the three risk factors Lee and colleagues mentioned have similar risk compared with women 5 to 10 years older without these risk factors. If these women can be identified at an earlier age when their risk is much higher than average, it is worthy to consider whether beginning screening earlier will be beneficial. Among women younger than 40 years, we would need to screen more than 1,000 women in order to detect one breast cancer — the abstract does not tell us the number needed to screen in this higher risk group.  

The reason the American Cancer Society recommends screening start no later than 45 years of age is because the burden of disease and the risk of harm does not significantly change between the ages of 45 to 49 years, and 50 to 54 years. Risk increases gradually, but overall among these 22 million women, the proportion of deaths from breast cancer, and the measures of premature mortality are about the same. Any woman between the ages of 40 to 44 years should have an opportunity to begin screening before the age of 45 years if she wants the reassurance and protection mammography screening provides; women in this age group have similar risk to women in their late 30s. Any woman younger than 40 years with a prior history of breast cancer would be expected to get regular mammograms, and thus, it is not unreasonable for women with a family history, especially a worrisome family history (a diagnosis in a first-degree relative under the age of 50 years) would begin screening before the age of 40 years.

A meeting abstract provides only a limited view of the authors’ research. We look forward to reviewing Lee and colleagues’ research findings upon eventual publication.

Douglas Owens, MD, MS

As a U.S. Preventive Services Task Force member, I am unable to comment on the findings of any specific study, such as Lee et al. However, I can provide a quick summary of the existing USPSTF definitions and recommendations involving breast cancer.

The Task Force’s recommendations apply to people who do not have any signs or symptoms of breast cancer and do not have preexisting breast cancer. Currently, the USPSTF recommends biennial screening mammography in these women aged 50 to 74 years. In women aged 40 to 49 years, the decision to start screening mammography is up to her. There is insufficient evidence to assess the balance of benefits and harms of screening mammography in women aged 75 years or older, as well as using digital breast tomosynthesis as a primary screening method for breast cancer in all women regardless of age, and of using adjunctive screening for breast cancer such as breast ultrasonography, MRI, digital breast tomosynthesis in women of any age with dense breasts.

The USPSTF defines women with above average risk for breast cancer as those who have family members with breast, ovarian, tubal or peritoneal cancer. Primary care physicians with patients that meet this criterion should use one of several screening tools designed to identify a family history that may be associated with an increased risk for potentially harmful mutations in BRCA1 or BRCA2. Although several risk tools are available, the tools evaluated by the USPSTF include the Ontario Family History Assessment Tool, Manchester Scoring System, Referral Screening Tool, Pedigree Assessment Tool and FHS-7. Those women with positive screening results should receive genetic counseling and, if indicated after counseling, BRCA testing.

These USPSTF recommendations and definitions on screening women for breast cancer are based on systematic reviews of the existing evidence. It’s important to note that for women in their 40s, conversations based on these recommendations should occur periodically, not only because a woman may find out more about her family history as she grows older, but also because the recommendations may change as she grows older and as additional evidence becomes available.

The USPSTF is aware that other medical groups offer guidelines and/or recommendations for screening women for breast cancer, and not all may be consistent with those of the USPSTF. We want women to be as informed as possible to make the best decision for themselves, given their own preferences and circumstances, and that includes knowing the potential benefits and harms, your family history, and whether you have dense breasts. Therefore, women of any age who are concerned about their risk for breast cancer should discuss their concerns with their clinician.