title: Menopausal hormone therapy and cancer: changing clinical observations of target site specificity.
abstract: Menopausal hormone therapy with estrogen plus progestin or estrogen alone (for women with prior hysterectomy) is still used by millions of women for climacteric symptom management throughout the world. Until 2002, hormone therapy influence on cancer risk and other chronic diseases was determined through observational study reports. Since then, results from the Women's Health Initiative randomized, placebo-controlled hormone therapy trials have substantially changed concepts regarding estrogen plus progestin and estrogen alone influence on the most common cancers in postmenopausal women. In these trials, estrogen plus progestin significantly increased breast cancer incidence and deaths from breast cancer, significantly increased deaths from lung cancer, significantly decreased endometrial cancer, and did not have a clinically significant influence on colorectal cancer. In contrast, estrogen alone use in women with prior hysterectomy significantly reduced breast cancer incidence and deaths from breast cancer without significant influence on colorectal cancer or lung cancer. These complex results are discussed in the context of known potential mediating mechanisms of action involved in interaction with steroid hormone receptors.
authors.affiliation: Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, United States. Electronic address: rowanchlebowski@gmail.com.
authors.forename: Rowan T
authors.initials: RT
authors.lastname: Chlebowski
authors.affiliation: Fred Hutchinson Cancer Research Center, Seattle, WA, United States.
authors.forename: Garnet L
authors.initials: GL
authors.lastname: Anderson
mesh_terms: D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology; D015914:Estrogen Replacement Therapy / Q000009:adverse effects; D004967:Estrogens / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects*; D006801:Humans; D017698:Postmenopause; D011372:Progestins / Q000009:adverse effects / Q000627:therapeutic use; D016032:Randomized Controlled Trials as Topic
chemical_list: D004967:Estrogens; D011372:Progestins
keywords: Cancer; Estrogen alone; Estrogen plus progestin; Menopausal hormone therapy