Prospective study of postpartum breast cancer and survival in women with germline BRCA pathogenic variants

In young-onset breast cancer (YOBC; diagnosed before age 46 years), a diagnose within 5 to 10 years of childbirth is associated with increased mortality. Women with BRCA1/2 pathogenic variants (PVs) are more likely to be diagnosed with BC at younger ages, but the impact of childbirth on mortality is unknown. A prospective study among 903 patients in the UK found that among patients with germline BRCA PVs and young-onset breast cancer, the all-cause mortality was increased if the BC diagnosis was within 10 years after last childbirth, with the highest risk for ER-positive BC diagnosed less than 5 years post partum and for ER-negative BC diagnosed 5 to less than 10 years post partum. BRCA1 carriers had a peak risk of mortality 5 to less than 10 years post partum, with no associations observed for BRCA2 carriers. The authors conclude that a breast cancer diagnosed within 10 years of childbirth was independently associated with increased risk for mortality in patients with BRCA1/2 PVs, especially for carriers of BRCA1 PVs.