HealthDay News — Women older than 65 years of age with estrogen receptor (ER)-negative breast cancer and perhaps all older women with breast cancer should be offered hereditary breast cancer testing, according to a study published online July 22 in the Journal of Clinical Oncology.

Nicholas J. Boddicker, PhD, from the Mayo Clinic in Rochester, Minnesota, and colleagues sought to estimate the frequency of pathogenic variants (PVs) and remaining risks for breast cancer for each gene in older women. The analysis included data from 26,707 women (aged great than 65 years) from population-based studies (51.5% with breast cancer and 48.5% unaffected) who were tested for PVs in germline predisposition genes.

The researchers found that the frequency of PVs in predisposition genes was 3.18% for women with breast cancer and 1.48% for unaffected older women. PVs in BRCA1, BRCA2, and PALB2 were identified in 3.42% of women diagnosed with ER-negative breast cancer, 1.0% of women with ER-positive breast cancer, and 3.01% of women with triple-negative breast cancer. Among women with no first-degree relatives with breast cancer, frequencies of PVs were lower. There were increased risks (odds ratio, 2.9 to 4.0) for breast cancer associated with PVs in CHEK2, PALB2, BRCA2, and BRCA1. For those with PVs in BRCA1, BRCA2, and PALB2, remaining lifetime risks for breast cancer were 15% or greater.

“This study suggests that all women diagnosed with triple-negative breast cancer or ER-negative breast cancer should receive genetic testing and that women over age 65 years with BRCA1 and BRCA2 PVs and perhaps with PALB2 and CHEK2 PVs should be considered for magnetic resonance imaging screening,” the authors write.

Several authors disclosed financial ties to the genetic testing industry.

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