BRCA1 and breast cancer: Guidelines recommend consideration of bilateral mastectomy for women newly diagnosed with breast cancer carrying pathogenic variants in BRCA1 or BRCA2 based on 20-year cumulative CBC risks of 40% and 26%, respectively (10-14), but recommendations for women with pathogenic or likely pathogenic (P/LP) variants in breast cancer predisposition genes other than BRCA1 or BRCA2 are not available, because cumulative long-term risks of a SBC are not well established.