Why is hormone therapy for breast cancer taken for several years?

Hormone therapy for breast cancer is often taken for several years because that is how it works best.

Researchers have studied hormone therapy as a breast cancer treatment for many decades. Results have shown that hormone therapy, when taken for 5 years or more, can greatly reduce the risk of new breast cancer, breast cancer recurrence, and dying from breast cancer.

Taking it consistently over this time is important. If side effects such as hot flashes or night sweats make it hard to continue, talk to your doctor rather than stopping on your own. Many side effects can be relieved by switching therapies or adjusting the dose. One common approach is to take tamoxifen for 2 or 3 years and then switch to an aromatase inhibitor.

Stopping or refusing hormone therapy is your decision, but your doctor can explain how effective it is likely to be for your specific diagnosis.