What's the difference between aromatase inhibitors and tamoxifen?
Both are hormone therapies for hormone receptor-positive breast cancer, but they work differently in your body.
How They Work:
Aromatase inhibitors block the enzyme that produces estrogen, lowering your body's estrogen levels by about 95 percent. They Show Full Answer
What's the difference between aromatase inhibitors and tamoxifen?
Both are hormone therapies for hormone receptor-positive breast cancer, but they work differently in your body.
How They Work:
Aromatase inhibitors block the enzyme that produces estrogen, lowering your body's estrogen levels by about 95 percent. They prevent estrogen from being made in the first place.
Tamoxifen is a selective estrogen receptor modulator (SERM) that blocks estrogen from attaching to receptors on breast cancer cells. It doesn't lower estrogen levels but prevents estrogen from fueling cancer growth.
Who Can Take Them:
Aromatase inhibitors are most effective for postmenopausal women because they can't stop the ovaries from making estrogen. Once your ovaries stop producing estrogen after menopause, these drugs work well.
Tamoxifen can be used both before and after menopause, making it more versatile for premenopausal women who need hormone therapy.
Effectiveness:
Research shows aromatase inhibitors prevent breast cancer recurrence about 30 percent more effectively than tamoxifen in postmenopausal women, making them the preferred first-line treatment after menopause.
Side Effects:
Aromatase inhibitors commonly cause muscle and joint pain and stiffness, and they don't increase uterine cancer risk or cause blood clots.
Tamoxifen can increase the risk of uterine cancer and blood clots but typically doesn't cause the joint pain associated with aromatase inhibitors.
December 29, 2025
Join
Your Privacy Choices
