Using HRT (Hormone Replacement Therapy) on breast cancer

Current or recent past users of hormonal replacement therapy (HRT) have a higher risk of being diagnosed with breast cancer. Before the link between HRT use and breast cancer risk was established, many postmenopausal women took HRT for many years to ease menopausal symptoms (hot flashes, fatigue) and to reduce bone loss. Since 2002, when research linked HRT and risk, the number of women taking HRT has dropped dramatically. Still, many women continue to use HRT to handle bothersome menopausal symptoms.
There are two main types of HRT:

• combination HRT contains the hormones estrogen and progesterone
• estrogen-only HRT contains only estrogen

Each type of HRT seems to have a different effect on breast cancer risk.
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. Higher-dose combination HRT increases breast cancer risk more than lower-dose combination HRT. Breast cancer risk goes back down to average about 2 years after you stop taking combination HRT.
Estrogen-only HRT increases the risk of breast cancer, but only when used for more than 10 years. Estrogen-only HRT also can increase the risk of ovarian cancer.
The higher breast cancer risk from using HRT is the same for so-called "bioidentical" and "natural" hormones as it is for synthetic hormones. "Bioidentical" means the hormones in the product are identical to the hormones your body produces. Bioidentical hormones are said to be "natural" -- derived from plants. Synthetic hormones are made in a lab and are also chemically identical to the hormones in your body. It's important to know that many herbal and bioidentical HRT products fall outside the jurisdiction of the United States Food and Drug Administration and so aren't subject to the same regulations and testing that medications are.