Table 4.

Relation of Breast Cancer Risk to Reproductive Surgery by Estrogen Receptor/Progesterone Receptor Status in the Women's Contraceptive and Reproductive Experiences Study, 1994–1998

Type of reproductive surgery	No. of Controls	Casesa vs. Controls			ER+/PR+ Casesa vs. Controls			ER−/PR− Casesa vs. Controls			ER+/PR+ Casesa vs. ER−/PR− Casesa
		No. of Cases	ORb	95% CI	No. of Cases	ORb	95% CI	No. of Cases	ORb	95% CI	ORb	95% CI
No reproductive surgery	2,174	1,668	1.00	Referent	1,143	1.00	Referent	525	1.00	Referent	1.00	Referent
Bilateral ovariectomy	527	257	0.63	0.52, 0.75	163	0.55	0.45, 0.68	94	0.82	0.63, 1.07	0.67	0.49, 0.92
Partial ovariectomyc with hysterectomy	224	128	0.75	0.60, 0.96	81	0.71	0.54, 0.93	47	0.88	0.62, 1.23	0.81	0.55, 1.19
Partial ovariectomyc without hysterectomy	228	149	0.87	0.70, 1.09	101	0.89	0.69, 1.14	48	0.84	0.60, 1.16	1.06	0.74, 1.53
Hysterectomy, no ovariectomy	539	330	0.81	0.69, 0.95	216	0.77	0.64, 0.93	114	0.91	0.72, 1.15	0.85	0.65, 1.11
Tubal sterilization only	919	630	0.98	0.86, 1.11	388	0.98	0.84, 1.13	242	0.97	0.81, 1.17	1.00	0.82, 1.23

Abbreviations: CI, confidence interval; ER−, estrogen receptor-negative; ER+, estrogen receptor-positive; OR, odds ratio; PR−, progesterone receptor-negative; PR+, progesterone receptor-positive.

^aNumber of cases excludes women with estrogen receptor/progesterone receptor status that was unknown, borderline, not determined, or unavailable.

^bAdjusted for age (continuous), race (white or black), study site (Atlanta, Detroit, Los Angeles, Philadelphia, or Seattle), age at menarche (years, continuous), first-degree family history of breast cancer (yes, no, or unknown/adopted), number of term pregnancies (0, 1, 2, or ≥3), educational status (some high school or less, high school graduate, some college or technical school, or college graduate or higher), and duration of hormone therapy use (never, 0–6 months, >6 months to <5 years, or ≥5 years).

^cNot bilateral; includes women with an unknown number of ovaries removed.