Effect of Hormone Replacement Therapy on Breast Cancer Risk: Estrogen Versus Estrogen Plus Progestin

作者：R K Ross · 发表于：JNCI Journal of the National Cancer Institute · 年份：2000 · DOI：10.1093/jnci/92.4.328 · 被引用次数：887 · 研究领域：Menopause: Health Impacts and Treatments、Estrogen and related hormone effects、Breast Cancer Treatment Studies

BACKGROUND: Hormone replacement therapy (HRT) given as unopposed estrogen replacement therapy (ERT) gained widespread popularity in the United States in the 1960s and 1970s. Recent prescribing practices have favored combination HRT (CHRT), i.e., adding a progestin to estrogen for the entire monthly cycle (continuous combined replacement therapy [CCRT]) or a part of the cycle (sequential estrogen plus progestin therapy [SEPRT]). Few data exist on the association between CHRT and breast cancer risk. We determined the effects of CHRT on a woman's risk of developing breast cancer in a population-based, case-control study. METHODS: Case subjects included those with incident breast cancers diagnosed over 4(1/2) years in Los Angeles County, CA, in the late 1980s and 1990s. Control subjects were neighborhood residents who were individually matched to case subjects on age and race. Case subjects and control subjects were interviewed in person to collect information on known breast cancer risk factors as well as on HRT use. Information on 1897 postmenopausal case subjects and on 1637 postmenopausal control subjects aged 55-72 years who had not undergone a simple hysterectomy was analyzed. Breast cancer risks associated with the various types of HRT were estimated as odds ratios (ORs) after adjusting simultaneously for the different forms of HRT and for known risk factors of breast cancer. All P values are two-sided. RESULTS: HRT was associated with a 10% higher breast cancer risk for e...