Increased Cancer Risk Found with Hormone Replacement Therapy

Combination Hormone Replacement Therapy –HRT–has been linked to increase breast cancer risks since 2002, but the risks may be even greater than originally thought. HRT is the most popular treatment for menopause symptoms, such as hot flashes and vaginal drying. However, the risks may outweigh the benefits and those hot flashes might be worth suffering through after all.

In 2002, a landmark Women’s Health Initiative (WHI) study was released linking higher risks for breast cancer, blood clots, and strokes to women who received combination hormone replacement therapy a therapy combining estrogen and progestin, often prescribed to help prevent common menopausal symptoms. Because of the alarming number of cases of breast cancer reported in the group of women receiving hormone replacement therapy, compared to those in the placebo group, the study was stopped early. That same year the use of HRT in the United States dropped significantly. Breast cancer rates also decreased in 2002. Prescriptions for Prempro and Premarin, combination hormone replacement therapies produced by Wyeth dropped from 60 million in 2001 to around 20 million by 2005. After the release of the WHI study, there was a lot of controversy as to the actual cause of the decline in the number of reported cases of breast cancer. Was it the decline in the use of combination therapy or the decrease in the number of mammograms administered identifying breast cancer?

Following the controversy, JoAnn Manson, a professor at Harvard Medical School and author of newly released analysis, along with colleagues, began to research the theory of hormone replacement therapy leading to an increased risk of breast cancer a little further. They evaluated two groups of women to determine what lead to the decline in breast cancer cases. The two groups consisted of the 15,000 women, who were evaluated, in the initial WHI study, along with 41,000 women who were enrolled in a separate study, beginning in 1994. According to Manson, women’s breast cancer risks decreased rapidly when hormone replacement therapy was haulted and changes in mammogram screenings doesn’t explain the decrease. Marcia Stefanick, a professor of medicine at Stanford University School of Medicine and co-author of the newly released analysis that can be found in the New England Journal of Medicine said, “A woman who continues combined hormone therapy after about five years would double her personal annual risk of breast cancer.” This risk is much greater than the risk of 27 percent originally reported in the landmark 2002 WHI study.

The new analysis found that in the initial two years of hormone replacement therapy there was no increase in the number of cases of breast cancer in those patients receiving combination HRT therapy. However, over five to six years of HRT treatment the groups’ odds increased significantly. Their odds decreased significantly once they stopped the treatment, which according to Professor Maria Stefanick is strong evidence of the link between combination hormone therapy, estrogen plus progestin, and breast cancer cases. She said, “You start women on hormones and within five years, their risk for breast cancer is clearly elevated. You stop the hormones and within one year, their risk is essentially back to normal. It’s reasonably convincing cause-and-effect.” Since the 2002 study, there have been several variations to the original study released. One actually evaluated cancer survivors’ risks of a relapse if using HRT therapy. They also reported increased chances of breast cancer after HRT therapy.

Many women may need relief from hot flashes or other effects of menopause. While research does link a higher risk of breast cancer with combination hormone replacement therapy, women can still benefit from the treatment, but according to researchers, patients should avoid long-term treatment with the therapy. It seems two years is the magic number for safe treatment through combination HRT. It is recommended that women stop the therapy after two years and see if their menopausal symptoms still persist. Then discuss further treatment and concerns if needed with their doctor.