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

Rationale and Objectives: Female carriers of pathogenic sequence variants (PSVs) in the BRCA1 /BRCA2 (Breast Cancer gene -BRCA) genes are at a substantially high-risk for developing breast cancer (BC), hence are offered active surveillance scheme based on semian-nual breast exam and imaging from age 25 years to facilitate BC early detection (mammography/breast ultrasound depending on the age, and MRI). However, there are not specific guidelines for screening in case of pregnancy or lactation. In the current study, we summarize the experience at the largest high-risk clinic in Israel.Materials and Methods: Data of consecutive BRCA-PSV carriers undergoing surveillance as well as diagnostic ultrasound at the Meirav high-risk clinic from January 2014 to 2021 who were pregnant and/or breastfeeding at time of follow-up were identified. Relevant clinical data including results of breast exam, breast ultrasonography, biopsies and histological results were retrieved. Percentage of biopsies with malignancy, cancer detection rate and positive predictive values were calculated. Data is presented in descriptive statistics.Results: A total of 263 BRCA-carriers were included. Of these, 593 breast-ultrasonograms were performed in 263 BRCA-carriers for 292 pregnancies and 409 breast-ultrasonograms for 175 breastfeeding carriers. Of 36 breast biopsies in 292 pregnancies, 4 (PPV = 11%) had BC diagnosed (high grade invasive). Of 175 breastfeeding women, 25 biopsies were performed and 2 (PPV = 8%) were high grade invasive BC. Five of 6 BC were diagnosed in BRCA1 carriers, and 4/6 were screen detected. The rate of pregnancy-associated breast cancer was 6/292 (2.05%).Conclusion: The overall detection rate of pregnancy-associated BC in BRCA-carriers is relatively low (2.05%), but still much higher than that in the general population. Two thirds of the BC were detected by screening. Therefore, despite the changes of the glandular breast tis-sue at time of pregnancy and breastfeeding, screening plays an important role in early detection. Ultrasound should be considered as a screening tool during this period of life of high-risk patients.