Thyroid function in postmenopausal breast cancer patients treated with tamoxifen

[anitab]

Anker GB, Lønning PE, Aakvaag A, Lien EA. Thyroid function in postmenopausal
breast cancer patients treated with tamoxifen. Scand J Clin Lab
Invest 1998; 58: 103–107.

Thyroid function was evaluated 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.

This is the abstract from a small study. I don't have the link, unfortunately.

Anita