Women who had breast cancer and took hormone replacement therapy (HRT) afterwards were no more likely to have a recurrence of the disease than those who did not use HRT, according to a study in the May 16 issue of the National Cancer Institute.
Many older women take HRT to relieve menopausal symptoms by elevating estrogen levels, which naturally decrease after menopause. Some studies have shown an association between HRT and breast cancer, although others have not. However, women who develop breast cancer while taking HRT have higher rates of survival than breast cancer patients with no estrogen supplementation. The use of HRT by women who have had breast cancer is controversial because some doctors fear that estrogen can stimulate a recurrence.
Katty Meara, Ph.D., and colleagues from the University of Washington studied the effects of HRT on recurrence in women with a history of breast cancer. They collected data from women ages 35 to 74 who were enrolled in a Seattle-based health plan between 1977 and 1994.
The researchers used health and pharmacy records to identify 174 women with a history of breast cancer who were also taking HRT. Each of these women was matched with four women of similar age and severity of breast cancer, but were not taking HRT. In all, data from 869 women (174 HRT users and 695 nonusers) were analyzed. The researchers compared users and nonusers of HRT after breast cancer with respect to breast cancer recurrence, breast cancer mortality, and total mortality.
Breast cancer recurrence was diagnosed in 9 percent of HRT users and 15 percent of nonusers. After adjusting for complicating factors, the researchers found that users had half the risk of breast cancer recurrence as nonusers.
Three percent of HRT users and 8 percent of nonusers died of breast
cancer during the follow-up period. Users had one-third the adjusted risk
of breast cancer mortality as nonusers.
During the follow-up period 10 percent of HRT users and 17 percent of nonusers died. The risk mortality from any cause was 52 percent less for users than nonusers.
The relative risks of recurrence or death did not vary significantly
among women who used HRT orally, vaginally, or both.
These results show HRT does not have an adverse impact on recurrent breast cancer. In fact, they suggest a protective effect since a far smaller percentage of users than nonusers developed new cancers or died.
The authors, however, stop short of endorsing HRT as beneficial with respect to recurrent breast cancer. They simply conclude that their “findings suggest that women who seek and use HRT after breast cancer do not have elevated risks of recurrence and death.”
In an accompanying editorial, Larry Cuzick, Ph.D, of the Imperial Cancer Research Fund in London, notes that Meara observation that HRT users have better survival rates than non-users raises doubts about clinician’s advice that women with breast cancer should avoid HRT.
He adds, “even if HRT turns out to have no effect on the prognosis of
breast cancer, this knowledge would be a major step forward in terms of
lowering morbidity and improving quality of life. One hardly dares
speculate on the possibility that HRT might be beneficial [for breast
cancer]; however, should this beneficial effect be confirmed in randomized
studies, the hormonal treatment of breast cancer will require very major
Tags: breast cancer, cancer, pharmacy