What's the difference between anastrozole and tamoxifen for breast cancer treatment?
Both anastrozole and tamoxifen are hormonal therapies used to treat hormone receptor-positive breast cancer, but they work in different ways and are used at different stages of life.
How They Work:
Anastrozole is an aromatase inhibitor Show Full Answer
What's the difference between anastrozole and tamoxifen for breast cancer treatment?
Both anastrozole and tamoxifen are hormonal therapies used to treat hormone receptor-positive breast cancer, but they work in different ways and are used at different stages of life.
How They Work:
Anastrozole is an aromatase inhibitor that blocks the production of estrogen in your body. It interferes with proteins called estrogen receptors to prevent breast cancer from returning.
Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks the effect of estrogen on breast cancer cells. It stops estrogen from encouraging cancer cells to grow and divide.
When They're Used:
Anastrozole is typically prescribed for people who have gone through menopause or are under treatment to suppress their ovaries. It's most useful after menopause when the ovaries stop making estrogen.
Tamoxifen can be taken whether or not you've gone through menopause, making it an option for premenopausal women.
Effectiveness:
Clinical trials show that aromatase inhibitors like anastrozole prevent breast cancer recurrence about 30 percent more effectively than tamoxifen. This makes aromatase inhibitors the preferred first-line hormone therapy for postmenopausal people with estrogen receptor-positive breast cancer.
Both medications are usually taken long term, most commonly for five to 10 years.
December 26, 2025