1523 / 1983
BRCA1
Oophorectomy
N = 617
BRCA2
Oophorectomy
N = 342
BRCA1
No
Oophorectomy
N = 415
BRCA2
No
Oophorectomy
N = 245
Mastectomy
Breast T
116
0
56
0
43
0
32
0
No mastectomy
Breast T
501
44 (8.8%)
286
20 (7%)
372
43 (10.4%)
213
15 (7%)
Protective effect of mastectomy on the risk of breast cancer
Domchek et al, 2010