Another HRT Study Cites Breast Cancer RiskMay 30, 2008 | Parker Waichman LLP
A recent study out of Germany found hormone replacement therapy (HRT) drugs - inlcuding Prempro and Premarin - taken for more than five years, increases one’s breast cancer risk, confirming earlier findings out of the United States.
Over 10,000 people between 50 and 74 were studied over six years: 3,464 breast cancer patients and 6,657 healthy women. The German survey was prompted by the "MARIE" case-control study carried out by the German Cancer Research Center (DKFZ) and the University Hospitals in Hamburg-Eppendorf, Germany. The study’s goal, which was financed by the German Cancer Aid (Deutsche Krebshilfe), was to determine hormone effects—on their own and with other factors—on breast cancer risk.
The study found that women who have already been treated with menopausal HRT have a 37 percent higher risk of breast cancer than women who never took HRT; during actual use, the risk increases by 73 percent. Within five years after cessation, the risk in former HRT users falls back to the same level of women who never used HRT. "These results of the MARIE study confirm findings of two U.S. and U.K. studies (Women's Health Initiative Study and Million Women Study) that caused a stir in 2002 and 2003," says Professor Dr. Wilhelm Braendle of Hamburg-Eppendorf University Hospitals, who headed the study.
"It has often been argued that the results of the U.S. study could not be applied to Germany where prescription practices are completely different. Therefore, we captured the various hormone preparations, especially the various progestins, very precisely. We have obtained similar results as the U.S. researchers," Professor Dr. Jenny Chang-Claude of DKFZ summarizes. "With our new data, we provide physicians in Germany with solid information that will help them to advise their patients about the benefits and risks of hormone replacement therapy."
The study confirms that different preparations have different effects. When compared to the risk of women who never used HRT, a combined estrogen and progestin therapy doubles the risk of breast cancer, while estrogen alone (estrogen replacement therapy) raises the risk by 15 percent. In both cases, the risk increases when hormones are taken for more than five years. "Hormone replacement therapy also appears to have a different influence on different types of breast cancer," Braendle explains. "The risk of developing one of the less common lobular or tubular breast cancers increases twice as much under HRT as the risk of the common type of ductal carcinoma, which constitutes 40 to 75 percent of all malignant tumors of the breast."
In January, U.S. researchers reported HRT significantly raises the risk of lobular breast cancer four-fold in women who took combined estrogen/progestin HRT for three years. That study is one of dozens looking to clarify the dangers of taking HRT to treat menopause symptoms. "Previous research indicated that five or more years of combined hormone-therapy use was necessary to increase overall breast-cancer risk," said Dr. Christopher Li of the Fred Hutchinson Cancer Research Center, who led the study. "Our study, the first specifically designed to evaluate the relationship between combined HRT and lobular breast cancers, suggests that a significantly shorter length of exposure to such hormones may confer an increased risk," he added.