There is little evidence supporting the recommendation that women with a first-degree relative (mother/sister/daughter) diagnosed with breast cancer, who are otherwise at average risk, should get screened 10 years earlier than the relative’s diagnosis age.
A recent study concluded that those with a relative diagnosed at or before age 45 may wish to consider screening five to eight years earlier than their relative’s diagnosis age, rather than a decade earlier.
The study, published in the American Cancer Society journal Cancer, was undertaken by UC Davis Comprehensive Cancer Centre researcher Diana Miglioretti and Danielle Durham, with the Department of Radiology at the University of North Carolina at Chapel Hill, and other researchers, who analysed data from the Breast Cancer Surveillance Consortium on screening mammograms conducted from 1996-2016 to evaluate when screenings should begin for women with a family history of breast cancer.
More than 300 000 women were included in the national study. The research team compared cumulative five-year breast cancer incidence among women with and without a first-degree family history of breast cancer by relative’s age at diagnosis and screening age.
“Our results concluded that a woman with a relative diagnosed at or before 45 may wish to consider, in consultation with her doctor, initiating screening five to eights years earlier than their relative’s diagnosis age, rather than a decade earlier. That puts them at a risk equal to an average-risk woman, aged 50, which is the most recommended age for starting mammograms,” said Durham.
BRCA gene mutation carriers may benefit from starting screenings earlier. Women aged 30-39 with more than one first-degree relative diagnosed with breast cancer might wish to consider genetic counselling.
Increasing the age for initiating screening could reduce the potential harms of starting breast cancer screenings too early. These include increased radiation exposure and false positive results that require women to return to the clinic for diagnostic imaging and possibly invasive procedures, but do not result in a breast cancer diagnosis. The earlier a woman starts receiving mammograms, the more screenings they will undergo over their lifetime, increasing the chances of experiencing these harms.
“Mammography also may not perform as well in younger women because they are more likely to have dense breasts, increasing the difficulty of finding cancer on the images and results in more false-positives,” Miglioretti said.
Study details
Breast cancer incidence among women with a family history of breast cancer by relative's age at diagnosis
Danielle Durham, Linn Abraham, Megan Roberts, Carly Khan,
Published in Cancer on 19 October 2022
Abstract
Background
Women with a first-degree family history of breast cancer are often advised to begin screening when they are 10 years younger than the age at which their relative was diagnosed. Evidence is lacking to determine how much earlier they should begin.
Methods
Using Breast Cancer Surveillance Consortium data on screening mammograms from 1996 to 2016, the authors constructed a cohort of 306,147 women 30–59 years of age with information on first-degree family history of breast cancer and relative's age at diagnosis. The authors compared cumulative 5-year breast cancer incidence among women with and without a first-degree family history of breast by relative's age at diagnosis and by screening age.
Results
Among 306,147 women included in the study, approximately 11% reported a first-degree family history of breast cancer with 3885 breast cancer cases identified. Women reporting a relative diagnosed between 40 and 49 years and undergoing screening between ages 30 and 39 or 40 and 49 had similar 5-year cumulative incidences of breast cancer (respectively, 18.6/1000; 95% confidence interval [CI], 12.1, 25.7; 18.4/1000; 95% CI, 13.7, 23.5) as women without a family history undergoing screening between 50–59 years of age (18.0/1000; 95% CI, 17.0, 19.1). For relative's diagnosis age from 35 to 45 years of age, initiating screening 5–8 years before diagnosis age resulted in a 5-year cumulative incidence of breast cancer of 15.2/1000, that of an average 50-year-old woman.
Conclusion
Women with a relative diagnosed at or before age 45 may wish to consider, in consultation with their provider, initiating screening 5–8 years earlier than their relative's diagnosis age.
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