Study: More Bad News About Linkage of HRT and Breast Cancer

Two new studies reported in the Journal of the American Medical Association have produced more bad news about the linkage between breast cancer and the hormone replacement therapy (HRT) taken by millions of women during and after menopause.

A study at Wayne State University in Detroit found that estrogen-progestin pills might cause an aggressive form of breast cancer and make it harder to find tumors until they have reached a less-curable stage.

And a study led by researchers at the Fred Hutchinson Cancer Research Center in Seattle found that older women who take the estrogen-progestin combination for a long time have a higher risk of breast cancer whether they take the progestin component all or part of each month.

The Wayne State Study :

In a study involving 16,608 women aged 50 to 79 who used either combined hormone treatment or placebos for an average of five years, breast cancer developed in 245 women using the hormone replacement therapy compared to 185 on the placebos.

The tumors for those taking hormones were larger at diagnosis, and had begun to spread in 25.4 percent of hormone users, compared with 16 percent of those on placebos. Overall, women on both hormones faced a 24 percent increased risk of breast cancer.

The Fred Hutchinson Study:

About 2,000 women 65 or older participated in this study.

While most women on hormone replacement therapy take a daily dose of estrogen and progestin, many take progestin only 10 to 15 days a month.

In this study, researchers found that women who took either regimen of combination hormone replacement therapy had double the risk of developing breast cancer of women who took no hormones, and the risk increased the longer the women took the drugs.

A federally funded study, the Women's Health Initiative, has produced a flood of data in the past year about the negative health effects of hormone therapy. Part of the study was halted last year after it became clear the use of hormone replacement therapy raised the risk of breast cancer, stroke, blood clots and heart disease (see earlier Breast Cancer Week story).

Other Sources: Journal of the American Medical Association