Thyroid function in postmenopausal breast cancer patients treated with tamoxifen

Abstract

Thyroid function was evaluation in 26 postmenopausal women with breast cancer before and at various time intervals during treatment with tamoxifen. Tamoxifen treatment suppressed plasma levels of FT3 and FT4 (p < 0.005 for both) and elevated plasma concentrations of TBG (p < 0.005 and TG (p < 0.025). In general, these changes became significant after 6 months of treatment. Plasma TSH increased significantly after 1 y of treatment (p < 0.025). A fall in FT4 and FT3 combined with increase in TSH suggests a reduced bioavailability of T4 and T3 during tamoxifen treatment. The increase in TG may reflect a reduced synthesis or liberation of T4 resulting in a reduced plasma level of FT4. Our findings suggest that tamoxifen influences the thyroid hormone levels, not only by modulating plasma TBG, but also by interfering with hormone synthesis or secretion in the thyroid gland.

Antithyroid peroxidase antibody positivity is associated with lower incidence of metastasis in breast cancer

“…Since Beatson (1) first described the use of thyroid extracts to treat patients with metastatic breast cancer over a century ago, a number of studies have investigated the association between thyroid disorders and breast cancer (2)(3)(4)(5)(6)(7)(8). However, despite extensive population studies, the results as a whole have been inconsistent.…”

Thyroid Function in Women after Multimodal Treatment for Breast Cancer Stage II/III: Comparison With Controls From a Population Sample

“…Conflicting evidence has been published on the possible effect of precancer TD on the development of BC (1)(2)(3)(4)(5)(6)(7). Furthermore, it has been debated whether BC by itself may induce TD or to what degree different BC treatments (radiotherapy [RT], chemotherapy, and antiestrogens) may alter thyroid function (8)(9)(10)(11)(12)(13)(14).…”

Seaweed and Soy: Companion Foods in Asian Cuisine and Their Effects on Thyroid Function in American Women

“…Following publication of studies during the trial on the effects of tamoxifen/roloxifen on thyroid function, [20][21][22] we excluded the three women who used tamoxifen during the entire study, and the one woman who started taking tamoxifen late in the trial had her last three observations omitted. Her earlier measures were included in the analysis.…”