Study: Long-Term HRT Use Tied to Higher Risk of Breast Cancer

Long-term hormone replacement therapy (HRT) has again been linked with breast cancer, according to a new report in the Journal of the American Medical Association.

Researchers at the Fred Hutchinson Cancer Research Center in Seattle conducted a study that included 705 postmenopausal women who had been diagnosed with primary invasive breast cancer and 692 women who were matched as controls.

The goal of the study was to ascertain the incidence and type of breast cancer by duration of HRT use in the 5-year period ending 1 year before diagnosis of the disease.

The results of the study showed that the incidence of breast cancer (both lobular and non-lobular) was 60 to 85 percent higher in recent long-term users of HRT, including those who used estrogen alone or in combination with progestin.

Longer use of HRT and current use of combination therapy regardless of duration were linked with an increased risk of lobular breast cancer. Long-term HRT was associated with a 50 percent increase in nonlobular cancer.

"Our data add to the growing body of evidence that recent long-term use of HRT is associated with an increased risk of breast cancer and that such use may be related particularly to lobular tumors," concluded the researchers.

Other Sources: Journal of the American Medical Association