Pregnancy Associated Breast Cancer Among Israeli BRCA1/BRCA2 Carriers in a High-Risk Clinic

Parity, breastfeeding, and the risk of early-onset breast cancer in women with a BRCA1 pathogenic variant

BACKGROUND

It is not clear if breastfeeding and/or parity are associated with the risk of breast cancer among women with a germline pathogenic variant in BRCA1. We sought to evaluate the associations of these two factors with early-onset breast cancer in the BRCA1 pathogenic variant.

METHODS

This case-control study included individuals with a BRCA1 pathogenic variant enroled in a longitudinal study using reproductive and disease histories ascertained at the time of enrolment. Cases had invasive breast cancer prior to age 45, and controls had no breast cancer prior to age 45. Logistic regression was used to evaluate the associations of parity and breastfeeding with cancer risk.

RESULTS

Parity per se was not associated with breast cancer risk (OR = 1.09; 95%CI 0.95-1.25); however, among women who never breastfed, the OR for parous vs. nulliparous women was 1.45 (95%CI 1.20-1.75). After matching for parity, ever breastfeeding was associated with 25% lower odds of breast cancer (95%CI 0.61-0.91), and the odds ratio was 0.53 (95%CI 0.40-0.72) for those who breastfed for 20 or more months.

DISCUSSION

Our findings suggest a potential role for breastfeeding in the prevention of young-onset breast cancer among individuals with a BRCA1 pathogenic variant and provide insight into possible prevention targets.

Breast cancer screening in BRCA1/2 pathogenic sequence variant carriers during pregnancy and lactation

OBJECTIVES

Women harboring germline BRCA1/BRCA2 pathogenic sequence variants (PSVs) are at an increased risk for breast cancer. There are no established guidelines for screening during pregnancy and lactation in BRCA carriers. The aim of this study was to evaluate the utility of whole-breast ultrasound (US) screening in pregnant and lactating BRCA PSV carriers.

METHODS

Data were retrospectively collected from medical records of BRCA PSV carriers between 2014 and 2020, with follow-up until 2021. Associations between imaging intervals, number of examinations performed and pregnancy-associated breast cancers (PABCs) were examined. PABCs and cancers diagnosed at follow-up were evaluated and characteristics were compared between the two groups.

RESULTS

Overall 212 BRCA PSV carriers were included. Mean age was 33.6 years (SD 3.93, range 25-43 years). During 274 screening periods at pregnancy and lactation, eight (2.9 %) PABCs were diagnosed. An additional eight cancers were diagnosed at follow-up. Three out of eight (37.5 %) PABCs were diagnosed by US, whereas clinical breast examination (n = 3), mammography (n = 1) and MRI (n = 1) accounted for the other PACB diagnoses. One PABC was missed by US. The interval from negative imaging to cancer diagnosis was significantly shorter for PABCs compared with cancers diagnosed at follow-up (3.96 ± 2.14 vs. 11.2 ± 4.46 months, P = 0.002).

CONCLUSION

In conclusion, pregnant BRCA PSV carriers should not delay screening despite challenges like altered breast tissue and hesitancy towards mammography. If no alternatives exist, whole-breast ultrasound can be used. For lactating and postpartum women, a regular screening routine alternating between mammography and MRI is recommended.

Controversies and Open Questions in Management of Cancer-Free Carriers of Germline Pathogenic Variants in BRCA1/BRCA2

Females harboring germline BRCA1/BRCA2 (BRCA) P/LPV are offered a tight surveillance scheme from the age of 25−30 years, aimed at early detection of specific cancer types, in addition to risk-reducing strategies. Multiple national and international surveillance guidelines have been published and updated over the last two decades from geographically diverse countries. We searched for guidelines published between 1 January 2015 and 1 May 2022. Differences between guidelines on issues such as primary prevention, mammography screening in young (<30 years) carriers, MRI screening in carriers above age 65 years, breast imaging (if any) after risk-reducing bilateral mastectomy, during pregnancy, and breastfeeding, and hormone-replacement therapy, are just a few notable examples. Beyond formal guidelines, BRCA carriers’ concerns also focus on the timing of risk-reducing surgeries, fertility preservation, management of menopausal symptoms in cancer survivors, and pancreatic cancer surveillance, issues that, for some, there are no data to support evidence-based recommendations. This review discusses these unsettled issues, emphasizing the importance of future studies to enable global guideline harmonization for optimal surveillance strategies. Moreover, it raises the unmet need for personalized risk stratification and surveillance in BRCA P/LPV carriers.