Timing of genetic testing in BRCA1/2 and PALB2-Associated breast cancer: Preoperative result disclosure increases uptake of risk-reducing mastectomy and reduces unnecessary exposure to radiotherapy

The impact of timing of genetic testing on uptake of risk reducing mastectomy (RRM) in affected female BRCA1/2 or PALB2 carriers remains an area of evolving interest, particularly with the introduction of mainstream genetic testing initiatives. Women with stage I-III breast cancer and a confirmed germline pathogenic variant in BRCA1/2 or PALB2 between 2000 and 2023 were identified from an institutional genetics database. Uptake of RRM was evaluated according to disclosure of genetic testing results before or after index surgery for a first diagnosis of breast cancer. The cohort included 287 female BRCA1/2 or PALB2 carriers with a median age of 44 years (IQR, 36–52). Overall, 155 (54 %) carriers received genetic testing results before and 132 (46 %) after index breast surgery. Receipt of genetic testing results before surgery was associated with a higher rate of index bilateral mastectomy (58.7 % vs. 7.6 %, p