Hormone therapy increase breast cancer risk across all ethnicities

Reported by Susan Aldridge, PhD, medical journalist

A study has shown there is no difference between ethnic groups when it comes to the increased risk of breast cancer linked to hormone replacement therapy.
Previous work has already revealed an increased risk of breast cancer among women on hormone replacement therapy (HRT). The risk is greatest among those on estrogen-progestin therapy. But most studies have focused upon white women, so a team at the University of Southern California has sought to broaden our knowledge of the risk by looking at data from the Multiethnic Cohort Study. This includes 215,251 men and women aged 45 to 75 living in Hawaii or California. They focused upon a sub-group of over 55,000 African-American, Native Hawaiian, Japanese American, Latina and White postmenopausal women.

They found that current use of estrogen-progestin therapy was linked to increased breast cancer risk - 29 per cent higher after five years of use. The association applied to women in all the ethnic groups. Current use of estrogen therapy was linked to a ten per cent greater risk after five years. The risks were, surprisingly, greater for lean than overweight women. HRT also seemed to have more impact on ductal and lobular carcinomas and there were varying effects on estrogen positive and negative tumors. The findings suggest that the increased risk of breast cancer with HRT is similar in women across all ethnic groups.

Source
International journal of Cancer online 16th September 2005

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