Another Study Finds Higher Breast Cancer Risk Among Women Who Use Hormone Replacement Therapy for Five Years or Longer (dateline April 30, 2002)
A new study published in the Journal of the American Medical Association shows that using hormone replacement therapy (HRT) for a period of five years (or more) increases a woman's risk of developing breast cancer. An estimated 20 million American women take some form of HRT to relieve menopausal symptoms or prevent bone loss associated with osteoporosis. There has been much debate in recent years surrounding the true benefits and risks of HRT. This study adds to previous research linking prolonged HRT use to breast cancer and underscores the need for women to talk to their physicians to determine whether HRT is right for them.
HRT has known benefits for menopausal and post-menopausal women. It is the most effective treatment for menopausal symptoms, such as hot flashes, vaginal dryness, and sleep disturbances. Most studies also find HRT to protect against bone loss and the bone-degenerative disease, osteoporosis. Over the years, it has also been suggested that HRT can prevent heart disease, help with Alzheimers disease and diabetes, and potentially provide a host of other benefits--although some of these benefits have been questioned in recent studies. Conflicting data also link HRT to an increased risk of breast cancer.
Beginning with the assumption that long-term HRT use increases breast cancer risk, Chi-Ling Chen, PhD, of Fred Hutchinson Cancer Research Center in Seattle, Washington, and colleagues set out to determine if HRT increases the likelihood that women will develop a certain type of breast cancer. The researchers analyzed medical data from 705 women between the ages of 50 and 74 who had been diagnosed with breast cancer between 1990 and 1995. These women's records were compared to a randomly selected group of 692 women.
The researchers found that the women who recently used HRT for five or more years were 60% to 84% more likely to develop breast cancer than non-HRT users. Furthermore, the researchers found that long-term use of HRT (five or more years) was associated with a 50% increased risk for ductal carcinoma, a common form of breast cancer that develops in the milk ducts, as well as an increased risk for lobular breast cancer--a type of breast cancer that accounts for approximately 10% of all cases.
While the American Cancer Society acknowledges that Dr. Chen's study is consistent with other research that has found a small increased risk of breast cancer among women who use HRT for five or more years, other experts question the study's small size. Thus, the debate over HRT continues.
Conflicting data from numerous studies over the last several years have made the link between HRT and breast cancer a controversial one among members of the medical community. Some studies have shown the risk of breast cancer to be minimal among women who use HRT while other studies have shown a more significant risk. Although studies have been inconsistent, there appears to be an emerging consensus that HRT increases breast cancer risk when taken for five years or longer, as Dr. Chen's study found. At the same time, the majority of studies suggest that HRT does not significantly increase the risk for breast cancer among women who take it less than five years or who take less than 0.625 mg of estrogen per day.
Until long-term studies can conclusively determine HRT's benefits and risks, women need to consider the current debate in terms of their own medical situations. To date, research appears to indicate that HRT is a tradeoff between the proven benefits of relieving menopausal symptoms and preventing diseases such as osteoporosis versus the possibility of increasing the risk for breast cancer. If a woman is at high risk of osteoporosis (due to age, family history, small build, etc.) and has a relatively low risk of breast cancer, then HRT may be the right decision for her. However, if a woman is already at high risk of breast cancer (due to genetic factors, family history, etc.), then the decision to take HRT may be more complicated. Women should discuss these issues with their physicians. In some cases, non-hormonal therapies (such as the drugs Fosamax or Actonel for osteoporosis) may be effective alternatives.