[Thyroid function after hypofractionated adjuvant radiotherapy for localized breast cancer]

Area of Science:

• Oncology
• Radiotherapy
• Endocrinology

Background:

• Adjuvant radiotherapy is a standard treatment for localized breast cancer.
• Hypofractionated radiotherapy regimens are increasingly used, potentially altering radiation exposure to organs at risk.
• The impact of hypofractionated radiotherapy on thyroid function requires further investigation.

Purpose of the Study:

• To evaluate the effect of hypofractionated adjuvant radiotherapy on thyroid function in breast cancer patients.
• To identify risk factors associated with radiation-induced thyroid dysfunction.

Main Methods:

• Prospective study of 50 breast cancer patients treated with hypofractionated adjuvant radiotherapy.
• Analysis of clinical, dosimetric, and biological data, including periodic thyroid hormone level monitoring.
• Inclusion of patients receiving radiotherapy to the supraclavicular region.

Main Results:

• The incidence of hypothyroidism was 4% among the studied patients.
• Significant association found between initial thyroid volume, volume receiving 50Gy, 40Gy, and 30Gy, and hypothyroidism incidence.
• No significant link between hypothyroidism and bilateral breast status, chemotherapy, hormone therapy, or surgery type.

Conclusions:

• Radiation-induced dysthyroidism is an underestimated complication of hypofractionated radiotherapy.
• Systematic delineation of the thyroid gland and dose minimization are recommended.
• Regular monitoring of thyroid function through serum assays is necessary in patients undergoing this treatment.