BRCA1 and breast cancer: Amongst PHTS patients with BC, better survival was observed with unilateral and bilateral mastectomy than with breast-conserving surgery (HRunilateral = 0.8, 95%CI = 0.2–3.7 and HRbilateral = 0.2, 95%CI = 0.03–0.9), consistent with some BRCA1/2 reports while other reports demonstrated no difference in survival [34, 35].