Oral contraceptives and the risk of death from breast cancer.
OBJECTIVE
To examine the relationship between the use of oral contraceptives and the risk of death from breast cancer.


METHODS
We used interview data from the Cancer and Steroid Hormone Study, linked to cancer registry data from the Surveillance, Epidemiology, and End Results Program, to examine the 15-year survival and prior use of oral contraceptives among 4,292 women aged 20 to 54 years when diagnosed with breast cancer from December 1, 1980, to December 31, 1982. Cox proportional hazard models were used to estimate the relative rate of death from breast cancer by oral contraceptive use.


RESULTS
Duration of oral contraceptive use, time since first use, age at first use, and use of specific pill formulations were not associated with survival. For time since last use, the risk of death from breast cancer decreased significantly with increasing time since last use of oral contraceptives, but a consistent gradient effect was not observed. Adjusted hazard ratios ranged from 0.86 to 1.41 and were 1.00 or less for all recency categories except during 13 to 24 months before diagnosis; none was statistically significant. Women who were currently using oral contraceptives had an adjusted hazard ratio of 0.90 (0.68, 1.19).


CONCLUSIONS
Overall, oral contraceptive use had neither a harmful nor a beneficial effect on breast cancer mortality. The differences between pill users and nonusers were slight, and the risk estimates were usually reduced with confidence limits that nearly always included 1.0.
Wingo
Phyllis A
PA
Division of Reproductive Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Austin
Harland
H
Marchbanks
Polly A
PA
Whiteman
Maura K
MK
Hsia
Jason
J
Mandel
Michele G
MG
Peterson
Herbert B
HB
Ory
Howard W
HW
D000328:Adult; D001943:Breast Neoplasms / Q000401:mortality*; D016022:Case-Control Studies; D003276:Contraceptives, Oral / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007407:Interviews as Topic; D008875:Middle Aged; D018570:Risk Assessment; D013997:Time Factors
D003276:Contraceptives, Oral