Akdeniz D, van Barele M, Heemskerk-Gerritsen BAM, et al. - Risk of contralateral breast cancer (CBC) is high among BRCA1/2 mutation carriers with primary breast cancer (PBC). Researchers herein examined if and how chemotherapeutic agents given for PBC affect CBC risk separately in BRCA1 and BRCA2 mutation carriers.

• From a Dutch cohort, researchers included 1,090 BRCA1 and 568 BRCA2 mutation carriers with an invasive PBC diagnosis.

• CBC risk decreases in BRCA1 in correlation with receiving chemotherapy for primary breast cancer.

• The largest CBC risk reduction was observed in BRCA1 in correlation with receiving anthracyclines with/without taxanes.

• BRCA2 had similar trends as observed in BRCA1 mutation carriers.

• Researchers recommend considering chemotherapy in personalized CBC risk models.