Combined estrogen and progestin hormone replacement therapy in relation to risk of breast cancer in middle-aged women.
OBJECTIVE
To determine the risk of breast cancer in relation to the use of combined estrogen and progestin hormone replacement therapy (HRT).


METHODS
A population-based case-control study.


METHODS
The general female population of King County in western Washington State.


METHODS
Middle-aged (50 to 64 years) women, including 537 patients with incident primary breast cancer diagnosed between January 1, 1988, and June 30, 1990, who were ascertained through the Seattle-Puget Sound Surveillance, Epidemiology, and End Results cancer registry and 492 randomly selected control women without a history of breast cancer.


METHODS
Breast cancer risk in relation to use of menopausal hormones.


RESULTS
Menopausal hormones of some type had been used by 57.6% of breast cancer cases and 61.0% of comparison women. The women who had ever taken combined estrogen-progestin HRT, representing 21.5% of cases and 21.3% of controls, were not at increased risk of breast cancer (relative odds [RO] = 0.9; 95% confidence interval [CI], 0.7 to 1.3). Compared with nonusers of menopausal hormones, those who used estrogen-progestin HRT for 8 or more years had, if anything, a reduced risk of breast cancer (RO = 0.4; 95% CI, 0.2 to 1.0).


CONCLUSIONS
On the whole, the use of estrogen with progestin HRT does not appear to be associated with an increased risk of breast cancer in middle-aged women. Nonetheless, since the use of combined estrogen-progestin HRT has only recently become prevalent, future investigations must assess whether breast cancer incidence is altered many years after estrogen-progestin HRT has been initiated, particularly among long-term users.
Stanford
J L
JL
Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
Weiss
N S
NS
Voigt
L F
LF
Daling
J R
JR
Habel
L A
LA
Rossing
M A
MA
D001943:Breast Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D016022:Case-Control Studies; D004359:Drug Therapy, Combination; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D004967:Estrogens / Q000009:adverse effects* / Q000627:therapeutic use; D005260:Female; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D011372:Progestins / Q000009:adverse effects* / Q000627:therapeutic use; D016016:Proportional Hazards Models; D012307:Risk Factors
D004967:Estrogens; D011372:Progestins