LA BioMed Researcher Says "Unexpected" Increase In Cancer Risk Found In Follow-Up Study To Women's Health Initiative

Main Category: Cancer / Oncology
Also Included In: Women's Health / Gynecology
Article Date: 04 Mar 2008 - 13:00 PDT

email to a friend   printer friendly   view / write opinions   rate article

An increased cancer risk in post-menopausal women after they stopped taking combined hormone therapy was an "unexpected finding" in a study that will be reported in the March 5 edition of the Journal of the American Medical Association (JAMA), said Rowan T. Chlebowski, M.D., Ph.D., a Los Angeles Biomedical Research Institute (LA BioMed) lead investigator who contributed to the study.

"This latest study reinforces the original finding that combined hormone therapy of estrogen plus progestin should not be taken for the purpose of reducing disease in post-menopausal women," Chlebowski said. "These findings also reinforce the need for monitoring for cancer in women who have taken the combination of estrogen plus progestin."

Dr. Chlebowski is a medical oncologist who has led several prior reports focusing on hormone effects on malignancies, including breast and colorectal cancer. He was a member of the team of researchers, led by Gerardo Heiss, M.D., of the University of North Carolina, Chapel Hill, N.C., who authored the March 5 JAMA report on a follow-up study of post-menopausal women enrolled in the Women's Health Initiative. Dr. Chlebowski is available for comment for reporters seeking further insight into the study's findings.

About the Women's Health Initiative

The Women's Health Initiative (WHI) trial began in 1993 to measure the effect of estrogen plus progestin on reducing disease in post-menopausal women. It included 16,608 postmenopausal women and assessed whether conjugated equine estrogens (CEE) plus medroxyprogesterone acetate (MPA) prevents heart disease and hip fractures and increases the risk of breast cancer.

The trial was stopped in 2002 when data indicated an increased risk of breast cancer and a failure to demonstrate an overall health benefit of the therapy. Further analysis showed that women taking the two hormones had higher risks of cardiovascular disease, coronary heart disease, stroke and venous thromboembolism and lower risks of fracture and colorectal cancer.

About the Follow-Up Study

After stopping intervention, WHI followed the trial participants using the same study protocol of semi-annual monitoring to identify and classify study outcomes, in order to evaluate the effects of stopping hormone therapy.

Post intervention information for the period July 8, 2002 to March 31, 2005 was available on 95% of the women. The JAMA article reports on health outcomes at three years after the intervention was stopped (mean of 2.4 years of follow-up).

In the three years after stopping hormone therapy women who previously used estrogen plus progestin no longer had an increased risk of cardiovascular disease (heart disease, stroke, and blood clots) compared with women on placebo.

The lower risk of colorectal cancer and fractures seen during the trial in women who previously used estrogen plus progestin disappeared after stopping the combined hormone therapy.

But the risk of all cancers combined in women who previously used estrogen plus progestin increased after stopping the intervention compared to those previously on placebo. This was due to increases in a variety of cancers, including lung cancer.

After stopping the hormone therapy, mortality from all causes was somewhat higher in women who previously used estrogen plus progestin compared with those taking a placebo.

About LA BioMed

Founded more than 55 years ago, LA BioMed is one of the nation's largest independent, not-for-profit biomedical 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 cardio-vascular disease, emerging infections, cancer, diabetes, kidney disease, dermatology, reproductive health, vaccine development, respiratory disorders, inherited illnesses and neonatology.

LA BioMed researchers have invented the modern cholesterol test, the thyroid deficiency test and a test to determine the carriers of Tay-Sachs disease, an inherited fatal disorder. One of the institute's researchers also developed the paramedic model for emergency care, setting a precedent that transformed emergency medical services and became the basis for training paramedics across the country.

Among LA BioMed's current research programs are a major effort to develop the next generation of antibiotics, new therapeutic and diagnostic approaches to lung disease, refining methods for earlier identification of Type II diabetes, studies in the relationship between cardiovascular and kidney diseases, development of enhanced breast cancer detection technology and a novel approach to treating several autoimmune diseases and certain solid tumors.

LA BioMed is an independent research institute that is academically affiliated with the David Geffen School of Medicine at the University of California, Los Angeles. The institute is located on the campus of Harbor-UCLA Medical Center near Torrance. The institute has become an economic engine for Los Angeles and Orange counties, pumping an additional $155 million into the economy in 2005, according to a 2007 Los Angeles Economic Development Corporation report. It contributes to the region'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.

http://www.LABioMed.org