CHICAGO (AP) -- New research suggests that long-term use of any type of hormones to ease menopause symptoms can raise a women's risk of breast cancer.

It is already known that taking pills that combine estrogen and progestin pills, the most common type of hormone therapy, can increase breast cancer risk. But women who no longer have a uterus can take estrogen alone, and this was thought to be safe and possibly even beneficial in terms of cancer risk.

But the new study suggests otherwise. It tracked the health of 60,000 nurses and found that use of any kind of hormones for 10 years or more raised the chances of developing breast cancer.

Results were discussed Sunday at a cancer conference in Chicago.