Women’s Health Initiative recently released new findings suggesting that Prempro hormone replacement therapy almost doubles the death risk from breast cancer.

A study conducted by the LA Biomedical Research Institute (LABRI) at harbor-UCLA Medical Center in 2002 found that the combination of estrogen and progesterone led to an increase in cases of breast cancer, making hormone replacement therapy generally a dangerous option for postmenopausal women. The study revealed that Prempro hormones, which were once used by millions of women, were in fact linked to higher rates of breast cancer and heart disease.

The initial findings in 2002 led to a decline in hormone use, with about 100,000 fewer invasive tumors detected from 2002-2007 than expected. The study continued to track 12,788 women for almost 8 years after the trials were stopped and found that for every 10,000 women, there were 2.6 deaths in those taking hormones and only 1.3 in those on a placebo.

These more recent findings conflict with previous studies showing that women with breast cancer who were taking hormones had a lower risk of death.

Peter Bach of Memorial Sloan-Kettering Cancer Center’s health outcomes research group said: “Given the substantial population of women who seek relief from menopausal symptoms and the large potential burden of disease that could be created if medications given to alleviate symptoms today cause cancer and other deaths tomorrow, it seems that additional randomized trials are needed”.