Tamoxifen and Thyroid Function in Breast Cancer Patients

The American Society of Clinical Oncology recommends considering the effects of tamoxifen on thyroid function when selecting treatments for postmenopausal breast cancer patients, as aromatase inhibitors like letrozole and exemestane do not cause clinically significant thyroid dysfunction 1, 2, 3

Drug Selection and Thyroid Function

For postmenopausal women with breast cancer, the National Comprehensive Cancer Network recommends aromatase inhibitors, such as anastrozole, letrozole, and exemestane, over tamoxifen when thyroid dysfunction is a concern, due to their lack of effect on thyroid function 1, 2, 3
The National Comprehensive Cancer Network suggests that for premenopausal women, tamoxifen remains the standard option, as aromatase inhibitors are not active in women with functioning ovaries 2, 3, 4