For women undergoing hormone replacement therapy (HRT) there is an increased risk of breast cancer, particularly when using combination HRT (estrogen-progestin). Estrogen-only HRT treatment has a much lower risk for breast cancer, and only with continued use of 10 years or more, though the risk for endometrial cancer does increase if you still have your uterus. It is considered that synthetic and bio-identical hormone replacement therapy carry the same level of risk. It’s important you are clear on these risks and can balance them against any symptoms you are experiencing.
On the flip side, HRT is used to treat cancer as it can ease symptoms and lessen the chance of the cancer returning.
Talk to your doctor to discuss what’s appropriate for you.