- Some patients with mutated BRCA1/2 genes may be undertreated with radiotherapy and overtreated with chemotherapy for early breast cancer.
Why this matters
- Patients carrying mutated genes may not be receiving guidelines-concordant care.
- A retrospective population-based cohort of 20,568 women with stages 0-III early breast cancer in the Georgia and California Surveillance, Epidemiology and End Results (SEER) database (2014-2016).
- Funding: NIH; others.
- BRCA1/2-positive patients were less likely than noncarriers to receive radiotherapy postlumpectomy (50.2% vs 81.5%; OR, 0.22; 95% CI, 0.15-0.32), which is nonconcordant with guidelines.
- BRCA1/2-positive patients with estrogen receptor (ER)-positive disease were more likely than noncarriers to receive chemotherapy (38.0% vs 30.3%; OR, 1.76; 95% CI, 1.31-2.34), which is nonconcordant with guidelines (which only call for endocrine therapy).
- BRCA1/2 carriers were more likely to receive bilateral mastectomy for unilateral tumors (61.7% vs 24.3%; OR, 5.52; 95% CI, 4.73-6.44), which was in accordance with guidelines.
- A similar pattern of results was seen for carriers of mutated genes other than BRCA1/2.
- Retrospective, observational design.
- Genetic test results may have been received after clinical decision-making.