Study finds no cancer risks from hormone replacement therapy within first two years

ATLANTA The American Cancer Society last week announced that there may be a two-year “safe period” for the use of hormone replacement therapies estrogen and progesterone.

According to a recently published study, new findings on the role of hormone use on the risk of breast cancer confirmed that the use of estrogen plus progesterone increases the risk of both ductal and lobular breast cancer by far more than estrogen-only, but found that the increased risk for ductal cancers observed in long-term past users of hormone replacement therapy drops off substantially two years after hormone use is stopped. They also found the risk associated with use of estrogen and progesterone increases significantly and substantially within three years of beginning hormone use. The data showed no increased risk for women who used estrogen and progesterone for less than two years, potentially identifying a “safe” period for estrogen and progesterone use.

The study appears in CANCER, a peer-reviewed journal of the American Cancer Society.

Previous studies have shown that hormone replacement therapy after menopause increases the risk of breast cancer and that use of a regimen that includes both estrogen and progesterone is more detrimental for the breast than the use of estrogen alone. But more data from large prospective studies are needed to fully characterize the impact of exogenous hormones on breast cancer incidence by type of hormone preparation and histology of the cancer.