Aromatase inhibitors, such as Letrozole or Anastrozole, are most useful in which patient group?

Aromatase inhibitors, such as Letrozole or Anastrozole, are most useful in which patient group?

• A. Premenopausal women with ER-positive tumors
• B. Postmenopausal women with ER-positive tumors
• C. Men with breast cancer
• D. Women with ER-negative tumors

Answer: (B)

Aromatase inhibitors decrease the amount of estrogen available to fuel ER-positive breast cancer by blocking the conversion of androgens to estrogens in peripheral tissues. This is especially effective in postmenopausal women, because after menopause, most estrogen comes from this peripheral aromatization rather than the ovaries. Lowering estrogen levels slows or stops growth of ER-positive tumors in this group. In premenopausal women, the ovaries still produce estrogen, and blocking aromatase can trigger feedback that increases ovarian estrogen production, making these drugs less effective unless combined with ovarian suppression. In men, breast cancer is less common and the data are not as strong; in ER-negative tumors there is no estrogen receptor to target, so aromatase inhibition doesn’t help. That’s why postmenopausal women with ER-positive tumors are the best-fit group for these medications.

Aromatase inhibitors decrease the amount of estrogen available to fuel ER-positive breast cancer by blocking the conversion of androgens to estrogens in peripheral tissues. This is especially effective in postmenopausal women, because after menopause, most estrogen comes from this peripheral aromatization rather than the ovaries. Lowering estrogen levels slows or stops growth of ER-positive tumors in this group.

In premenopausal women, the ovaries still produce estrogen, and blocking aromatase can trigger feedback that increases ovarian estrogen production, making these drugs less effective unless combined with ovarian suppression. In men, breast cancer is less common and the data are not as strong; in ER-negative tumors there is no estrogen receptor to target, so aromatase inhibition doesn’t help. That’s why postmenopausal women with ER-positive tumors are the best-fit group for these medications.