Estrogen-only HRT contains only estrogen
Combination HRT increases breast cancer risk by about 75%,
even when used for only a short time. Combination HRT also
increases the likelihood that the cancer may be found at a
more advanced stage, as well as increasing the risk that a
woman diagnosed with breast cancer will die from the
disease. Breast cancer risk increases the most during the first
2 to 3 years of taking combination HRT.