(HealthDay News) — Women who have a first-degree relative diagnosed with breast cancer at or before age 45 may benefit from starting breast cancer screening 5 to 8 years earlier than their relative’s diagnosis age, according to a study published in Cancer.

Danielle D. Durham, PhD, from the University of North Carolina at Chapel Hill, and colleagues studied a cohort of 306,147 women aged 30 to 59 years with information on a first-degree family history of breast cancer. The researchers compared cumulative 5-year breast cancer incidence between women with and without a first-degree family history of breast cancer according to screening age and the relative’s age at diagnosis.

About 52% of the cohort had a screening mammogram between the ages of 40 and 49 years, 11% had a first-degree family history of breast cancer, and 8% reported the relative’s age at breast cancer diagnosis.


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The estimated cumulative 5-year incidence of breast cancer was 13.8 per 1000 in the study cohort overall, 13.0 per 1000 for patients without a first-degree family history of breast cancer, and 19.9 per 1000 for patients with a family history.

The 5-year estimated cumulative incidence of breast cancer increased as a relative’s diagnosis age decreased. The incidence was 10.9 per 1000 for patients who underwent screening mammography between 30 and 39 years of age and had a first-degree family history of breast cancer. This was similar to the 11.0 per 1000 incidence for patients without a first-degree family history who underwent screening mammography between 40 and 49 years of age.

Patients who underwent screening between 30 and 39 years of age and had a relative diagnosed between 40 and 49 years of age had a 5-year estimated cumulative incidence of breast cancer of 18.6 per 1000. The incidence was 18.0 per 1000 in patients without a first-degree family history who underwent screening between 50 and 59 years of age.

For patients with a relative diagnosed at 35 to 45 years of age, starting screening 5 to 8 years before the relative’s age at diagnosis yielded a 5-year cumulative incidence of breast cancer of 15.2 per 1000. This is the same incidence as that of an average-risk 50-year-old woman.

“[O]ur findings suggest women with a relative diagnosed at or before age 45 may consider initiating screening 5-8 years earlier than their relative’s diagnosis age if they wish to initiate screening when their 5-year absolute risk is equivalent to that of an average-risk 50-year-old woman,” the authors wrote.

One author has received book royalties from Elsevier; a second author disclosed financial ties to GRAIL, a biotechnology company.

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