Study: HRT Use After Breast Cancer May Lower Risk of Recurrence

Hormone replacement therapy in women with invasive breast cancer may be associated with a lower risk of breast cancer recurrence, breast cancer deaths, and overall mortality, according to researchers at the University of Washington.

Because estrogen has been linked with the growth of some cancerous tumors, post-menopausal women with breast cancer have avoided the hormone. Researchers now suggest that breast cancer patients should not be afraid of taking hormone replacement therapy, according to the study published in the Journal of the National Cancer Institute.

"The data are reassuring for women who take HRT after a breast cancer diagnosis," said Dr. Ellen O'Meara, cancer researcher at the University of Washington and author of the study. "HRT need not be ruled out automatically."

The study consisted of 174 women who began using HRT after a breast cancer diagnosis and were recurrence free at the onset of the study. Each of the participants was matched by age, disease and year of diagnosis with four randomly selected patients not taking HRT.

The researchers then compared the long-range outcomes of both groups, tracking the participants for recurrence for 3.7 years and death for 4.6 years. The women averaged using HRT for 15 months and nearly 80 percent of the HRT users took estrogen without progesterone.

Researchers found that the rate of cancer recurrence in the HRT group was 17 per 1,000 person-years (one person-year is one year of life) and the non-HRT user group rate was 30 per 1,000 person-years.

Death resulting from breast cancer was 5 per 1,000 person-years for users of HRT and 15 per 1,000 person-years for nonusers.

The study revealed data that suggested HRT may increase the risk of cancer in a previously unaffected breast, with the risk of developing tumors in the unaffected breast being 12 per 1,000 person-years for the HRT group and 8 per 1,000 person-years in the non-HRT group.

This is a result too small for strong statistical conclusions, said O'Meara. Researchers admit that the study is not definitive because of its small size and a larger study is needed to confirm the results. Two larger studies on the link of HRT with breast cancer are underway in Sweden and the UK.

Other sources: Journal of the National Cancer Institute, AP