Plasma thyroid-stimulating hormone and thyroxine concentrations in breast cancer

Area of Science:

• Endocrinology
• Oncology

Background:

• Thyroid hormones play a crucial role in cellular metabolism and function.
• Alterations in thyroid function have been observed in various cancer types, but the specific relationship with breast cancer requires further elucidation.

Purpose of the Study:

• To investigate plasma thyroid stimulating hormone (TSH) and thyroxine levels in patients with early and advanced breast cancer.
• To compare thyroid function markers between breast cancer patients and those with cancers in other organs, as well as healthy controls.

Main Methods:

• Measurement of plasma TSH and thyroxine levels in 74 early breast cancer patients, 53 advanced breast cancer patients, 77 patients with other cancers, and 67 healthy controls.
• Statistical analysis to compare mean TSH levels and the prevalence of elevated TSH concentrations across the groups.
• Assessment of TSH response to thyrotropin-releasing hormone (TRH) in a subset of early breast cancer patients.

Main Results:

• Mean plasma TSH levels were higher in breast cancer patients than in other groups, with statistical significance noted in advanced disease.
• Elevated plasma TSH concentrations were observed in 12% of early and 15% of advanced breast cancer patients, versus 1% and 3% in other cancer patients and controls, respectively.
• Four breast cancer patients with very high TSH levels (>85 microIU/ml) had subnormal thyroxine levels; 17% of early breast cancer patients showed excessive TSH response to TRH.

Conclusions:

• Breast cancer is associated with altered thyroid stimulating hormone levels, particularly in advanced stages.
• A subset of breast cancer patients may experience thyroid dysfunction, indicated by elevated TSH and, in some cases, subnormal thyroxine or exaggerated TSH response to TRH.