Breast Cancer Risk Rapidly Declined After Women Stopped Taking Postmenopausal Combined Hormone Therapy

Main Category: Menopause
Also Included In: Breast Cancer;  Endocrinology;  Women's Health / Gynecology
Article Date: 05 Feb 2009 - 7:00 PDT

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Women who stopped taking the postmenopausal hormone combination of estrogen plus progestin experienced a marked decline in breast cancer risk which was unrelated to mammography utilization change, according to a study from the Women's Health Initiative led by a Los Angeles Biomedical Research Institute (LA BioMed) investigator.

The study, based on data from the Women's Health Initiative, will be published Wednesday in The New England Journal of Medicine.

"These findings support the hypothesis that the recent reduction in breast cancer incidence in the United States is predominantly related to a decrease in combined estrogen plus progestin use," said Rowan T. Chlebowski, M.D., Ph.D., a LA BioMed chief investigator and lead author for the study.

Breast cancer in the United States began to decline in 2003, after the Women's Health Initiative's initial findings that combined hormone therapy was related to higher risk of breast cancer and heart problems.

Using data from the Women's Health Initiative randomized trial and observational study cohort of postmenopausal women on combined hormone therapy, the researchers in the study published today also found that continued use of combined estrogen plus progestin after five years about doubles subsequent breast cancer risk each year.

"Postmenopausal women and their physicians should consider these findings in weighing the risks and benefits of combined estrogen plus progestin use, especially if they plan to take the medication for more than five years," said Dr. Chlebowski.

The National Heart, Lung and Blood Institute provided grants to support this study of data from the Women's Health Initiative. The National Institutes of Health established the Women's Health Initiative in 1991 to address the most common causes of death, disability and impaired quality of life in postmenopausal women, including the use of combined hormone therapy. That part of the study was halted in 2002 when researchers saw surprisingly higher rates of heart problems and breast cancer in women taking the hormones.

About LA BioMed

Founded 56 years ago, LA BioMed is one of the country's largest not-for-profit independent biomedical research institutes. It conducts biomedical research, trains young scientists and provides community services, including childhood immunization, nutrition assistance and anti-gang violence programs. The institute's researchers conduct studies in such areas as cardiovascular disease, emerging infections, cancer, diabetes, kidney disease, dermatology, reproductive health, vaccine development, respiratory disorders, inherited illnesses and neonatology.

LA BioMed is an independent institute that is academically affiliated with the David Geffen School of Medicine at UCLA. The institute is located on the campus of Harbor-UCLA Medical Center near Torrance. It contributes to Los Angeles County's economic viability while inventing the future of health care through its ground-breaking research, its training of the scientists of tomorrow and its service to the local community. Please visit our website at http://www.LABioMed.org

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