Assessment of Genetic Mutations in Postmenopausal Women With Breast Cancer
Posted: Monday, June 29, 2020
Postmenopausal women with newly diagnosed breast cancer may benefit from genetic testing for inherited cancer–associated mutations, even in the absence of an early diagnosis age or family history. Allison W. Kurian, MD, MSc, of Stanford University in California, and colleagues published their analysis of the prevalence of pathogenic variants in breast cancer in a Research Letter in JAMA.
“There’s been a lot of controversy in the field as to whether every woman with breast cancer should receive genetic testing,” said Dr. Kurian in a Stanford Medicine press release, “in part because we didn’t know how prevalent cancer-associated mutations are in this [group of] women who develop breast cancer after menopause without the presence of any known hereditary risk factors.”
Researchers used information from the Women’s Health Initiative, which enrolled postmenopausal women aged 50 to 79 from 1993 to 1998. Patients in this study did not have a history of breast cancer at the time of enrollment in the initiative, but they were either diagnosed with invasive cancer (case) or remained free of cancer (control) as of September 2017. Next-generation sequencing was performed using a 28-gene panel, which included these breast cancer–associated genes: BRCA1/2, ATM, CHEK2, TP53, BARD1, CDH1, NBN, PALB2, and STK11. Variants in these genes were classified as pathogenic, likely pathogenic, of uncertain significance, likely benign, or benign.
Pathologic variants in these genes were identified in 241 of the 4,517 women included in the study (148 in the breast cancer group and 93 in the control group). A pathologic variant was detected in any breast cancer–associated gene in 3.55% of case participants and 1.29% of control patients. Of all patients with BRCA1/2 pathologic variants, 30.8% of those with breast cancer and 20% of those without met testing guidelines. The prevalence of BRCA1/2 pathologic variants was 2.21% in the patients with breast cancer who were diagnosed before age 65 and 1.09% in patients diagnosed at age 65 or older.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.