Thyroid function in postmenopausal women with breast cancer on tamoxifen.
In 42 postmenopausal women with breast cancer, aged 48-85 years (mean age 62.4 years) serum thyroid hormone concentrations were measured before and after 6 months of tamoxifen therapy (20 mg daily). In particular triiodothyronine (T3), thyroxine (T4), free triiodothyronine (FT3), free thyroxine (FT4), thyroxine-binding globulin (TBG) and thyroid-stimulating hormone (TSH) concentrations before and 30 minutes after thyrotrophin-releasing hormone (TRH) administration (200 microg i.v.) were measured before and 6 months after tamoxifen therapy. T3 and T4 concentrations increased significantly (p<0.001 and p<0.05, respectively) whereas FT3 and FT4 remained unchanged (p>0.05), TBG increased significantly (p<0.001) and basal TSH concentrations as well as TSH response to TRH injection increased significantly (p<0.05) after tamoxifen therapy. It is concluded that tamoxifen administration changes thyroid hormone concentrations. However free thyroid hormone levels remain unchanged and the patients remain euthyroid after long-term tamoxifen therapy.
Kostoglou-Athanassiou
I
I
Department of Medical Physics, Medical School, University of Athens, Greece.
Ntalles
K
K
Markopoulos
C
C
Athanassiou
P
P
Gogas
J
J
Proukakis
C
C
D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000097:blood / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy* / Q000601:surgery; D017024:Chemotherapy, Adjuvant; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D017698:Postmenopause; D011379:Prognosis; D011863:Radioimmunoassay; D013629:Tamoxifen / Q000097:blood / Q000627:therapeutic use*; D013960:Thyroid Function Tests; D013963:Thyroid Hormones / Q000097:blood; D013997:Time Factors
D018931:Antineoplastic Agents, Hormonal; D013963:Thyroid Hormones; D013629:Tamoxifen