New Analysis Says Evidence Lacking for HRT-Breast Cancer Link

Researchers took fresh look at three large studies, concluded data wasn't convincing.

By Kathleen Doheny
HealthDay Reporter

THURSDAY, March 14 ( HealthDay News) -- Although several large studies in recent years have linked the use of hormone therapy after menopause with an increased risk of breast cancer, the authors of a new analysis claim the evidence is too limited to confirm the connection.

Dr. Samuel Shapiro, of the University of Cape Town Medical School in South Africa, and his colleagues took another look at three large studies that investigated hormone therapy and its possible health risks -- the Collaborative Reanalysis, the Women's Health Initiative (WHI) and the Million Women Study.

Together, the results of these studies found overall an increased risk of breast cancer among women who used the combination form of hormone therapy with both estrogen and progesterone. Women who have had a hysterectomy and use estrogen-only therapy also have an increased risk, two of the studies found. The WHI, however, found that estrogen-only therapy may not increase breast cancer risk and may actually decrease it, although that has not been confirmed in other research.

After the WHI study was published in July 2002, women dropped hormone therapy in droves. Many experts pointed to that decline in hormone therapy use as the reason breast cancer rates were declining.