Breast Cancer Coverage from Every Angle

Germline Genetic Testing and Treatment Variation in Women With Breast Cancer

By: Hillary Ojeda
Posted: Monday, May 4, 2020

According to a study of more than 20,000 women, published in JAMA Oncology, not all women with early-stage breast cancer and an inherited genetic variant are receiving guideline-adherent treatment. Steven J. Katz, MD, MPH, of the Department of Medicine, Stanford University, California, and colleagues suggest further research is needed to understand long-term outcomes as well as the therapeutic implications of genetic testing after diagnosis.

“Cancer treatment options are increasingly more complex for patients. Patients must consider a myriad of treatment options for the cancer they have and the implications of genetic test results on cancer prevention strategies for themselves and their family members,” said Dr. Katz in a University of Michigan press release.

A total of 20,568 women, out of 119,198 women, were eligible for the population-based cohort study. The women were 20 years or older and were diagnosed with stages 0 to III breast cancer between 2014 and 2016. Their data came from the Surveillance, Epidemiology, and End Results (SEER) registries of Georgia and California. They had genetic testing within 3 months after diagnosis. The study authors analyzed the clinical scenarios—surgery, radiotherapy, and chemotherapy—of the patients and noted their varying genetic results.

Women with BRCA1/2 pathogenic variants had a higher association of receiving bilateral mastectomy for a unilateral tumor and were less likely to receive postlumpectomy radiotherapy than women who tested negative for the variant. Specifically, 66% of BRCA-positive patients underwent double mastectomy, compared with 24% of those with a negative genetic test result. These patients were also more likely to receive chemotherapy for early-stage estrogen receptor/progesterone receptor–positive disease. Other breast cancer–associated genes showed similar results.

Disclosure: The study authors’ disclosure information can be found at

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