Menopausal estrogen use and the risk of breast cancer

Abstract

The relationship between the occurrence of female breast cancer and menopausal estrogen replacement was investigated in a population-based case-control study. One hundred and eighty-three white female residents of King County, Washington (ages 50-74) in whom breast cancer was diagnosed from July, 1977, through August, 1978, were interviewed with respect to reproductive and other factors, with emphasis on the use of estrogen-containing medication. For purposes of comparison, the same data were collected from 531 white female King County residents of the same ages without breast cancer. Use of menopausal estrogens was reported somewhat more commonly among controls than among cases (relative risk = 0.74, 95% confidence interval = 0.51-1.08) and some variation in proportions of users was present between different hysterectomy-oophorectomy subgroups. However, each of these differences could easily have been due to chance. No substantial trends in risk were apparent with increasing duration of use, time since first use, time since last use, or average dose. The findings suggest that in King County no important relationship exists between use of menopausal estrogens and the occurrence of breast cancer.

Association between lifestyle, menstrual/reproductive history, and histological factors and risk of breast cancer in women biopsied for benign breast disease

“…Contrary to our study, in which we observed a strong positive association, two studies provided null findings for the association between HRT use and breast cancer among women with BBD (5,31), while inverse associations were reported by two earlier studies (32,33). Nonetheless, findings from our study are consistent with those from previous studies which indicate a greater risk of breast cancer among HRT users than non-users (34–36).…”

Outcome of breech delivery at term.

“…1977;Wynder et al 1978;Ravinhar et al 1979;Kelsey el al. 1981;Sherman et al, 1983;Horwitz & Stewart 1984;Kaufman et al 1984;McDonald et al 1986); follow up studies that found an increased risk (Hoover et al 1976;Bergkvist et al 1989); and follow up studies that found no increased risk (Nachtigall et al 1979;Bland et al 1980;Buring et al 1987;Dupont et al 1989;Hunt & McPherson 1990). Since publication of that review, two further studies (Kaufman et al 1991;Palmer et al 1991) show conflicting results.…”

Chapter II. Breast-Cancer Etiology

“…Although several case-control studies have failed to show any association between estrogen treatment of climac-teric women and the development of breast cancer (Kelsey et al, 1981;Kaufman et al, 1984;McDonald et al, 1986;Wingo et al, 1987;Kelsey and Hildreth, 1983;Brinton, 1984;Ernster et al, 1988;Key and Pike, 1988), other case-control studies (Ross et al, 1980;Jick et al, 1980;Brinton et al, 1981Brinton et al, , 1986Hoover et al, 1981;Hulka et al, 1982;Thomas et al, 1982;Hiatt et al, 1984;La Vecchia et al, 1986;Ewertz, 19883) and 4 cohort studies (Hoover et al, 1976;Hunt et al, 1987;Buring et al, 1987;Bergkvist et al, 1989a) have indicated that an association between estrogen replacement and breast cancer may exist. In these positive studies, the overall incidence rate ratio for ever-users has been 10%40% higher than the rate among never-users (Hoover et al, 1976(Hoover et al, , 1981Brinton et al, 1981;Bergkvist et al, 1989b), although one cohort study revealed a 60% increased risk overall and 70% excess risk for women who had used potent estrogens for 7-10 years or more (Hunt et al, 1987).…”