Table 2.

Person-years, number of incident breast cancers, and incidence of breast cancer among all women and stratified by oophorectomy status and BRCA mutation status

Variable	Person- years	No. of events	Incidence, %
BRCA1 and BRCA2 mutation carriers (n = 3722)
All	20 700	350	1.69
No oophorectomy*	13 052	207	1.59
Oophorectomy*	7648	143	1.87
BRCA1† mutation carriers (n = 2969)
All	16 860	292	1.73
No oophorectomy*	10 806	170	1.57
Oophorectomy*	6055	122	2.02
BRCA2† mutation carriers (n = 725)
All	3713	57	1.54
No oophorectomy*	1550	36	2.32
Oophorectomy*	2163	21	0.97
Censored at age 50 y‡
BRCA1† mutation carriers (n = 2453)
All	12 302	194	1.58
No oophorectomy*	9594	140	1.46
Oophorectomy*	2708	54	1.99
BRCA2† mutation carriers (n = 508)
All	2156	30	1.39
No oophorectomy*	1585	27	1.70
Oophorectomy*	571	3	0.53

^*Oophorectomy refers to bilateral oophorectomies only.

†Women with both a BRCA1 and BRCA2 mutation were coded as missing.

‡Follow-up was censored at age 50 years; thus, women older than age 50 years at baseline were excluded from this analysis.