Pre-diagnosis oophorectomy, estrogen therapy and mortality in a cohort of women diagnosed with breast cancer

Table 2 Hazard ratios (95% CI) for mortality according to gynecologic surgery and estrogen use prior to breast cancer diagnosis, Collaborative Breast Cancer Studies

	Person-years	All-cause mortality		Breast cancer mortality		Cardiovascular disease mortality
		Deaths	HR (95% CI)^a	Deaths	HR (95% CI)^b	Deaths	HR (95% CI)^b
Intact uterus and ovaries, never hormone use	43,221	1,877	1	661	1	326	1
TAHBSO^c	17,549	557	0.84 (0.76, 0.92)	198	0.76 (0.64, 0.90)	94	0.84 (0.67, 1.06)
Age at surgery:
≤ 45 years	6,459	218	0.86 (0.75, 0.99)	71	0.85 (0.66, 1.09)	43	1.04 (0.75, 1.44)
> 45 years	11,090	339	0.82 (0.73, 0.92)	127	0.86 (0.71, 1.05)	51	0.73 (0.54, 0.98)
Unopposed estrogen use:
Never used hormones	5,397	241	0.92 (0.80, 1.05)	59	0.73 (0.55, 0.96)	58	1.19 (0.89, 1.58)
Used unopposed estrogen	10,245	270	0.78 (0.69, 0.89)	120	0.97 (0.80, 1.18)	31	0.57 (0.39, 0.83)
Duration of estrogen use:
6 months- 4.9 years	2,765	80	0.81 (0.65, 1.02)	39	0.73 (0.56, 0.96)	12	0.72 (0.41, 1.29)
5 - 9.9 years	2,349	49	0.75 (0.56, 0.99)	23	1.19 (0.84, 1.66)	6	0.68 (0.30, 1.55)
≥ 10 years	5,131	141	0.77 (0.65, 0.92)	58	0.76 (0.50, 1.19)	13	0.45 (0.26, 0.78)

^aHazard ratios adjusted for age, study enrollment years, state, body mass index, cigarette smoking, family history of breast cancer, and stage at diagnosis; ^bcumulative incidence subhazard ratios adjusted for age, study enrollment years, state, body mass index, cigarette smoking, family history of breast cancer, and stage at diagnosis; ^cTAHBSO, total abdominal hysterectomy and bilateral salpingo-oophorectomy.