Thyroid dysfunction in patients treated with radiotherapy for neck.

Area of Science:

• Endocrinology
• Oncology
• Radiotherapy

Background:

• Head and neck cancer treatment often involves radiation therapy, which can affect thyroid function.
• Understanding the incidence and timing of thyroid dysfunction post-radiation is crucial for patient management.

Purpose of the Study:

• To retrospectively assess early and late thyroid dysfunction following radiation therapy for head and neck cancer.
• To evaluate the impact of surgery in conjunction with radiation therapy on thyroid function.

Main Methods:

• Retrospective analysis of 63 patients who received neck irradiation including the thyroid gland.
• Patients were categorized based on whether they underwent neck dissection (36 patients) or received radiotherapy as primary treatment (27 patients).

Main Results:

• Thyroid dysfunction was observed in a significant portion of patients: 38% developed hypothyroidism (HT), with 12.7% clinical HT and 25.4% subclinical HT.
• Median time to clinical HT was 15 months, and subclinical HT was 3 months. Subclinical hyperthyroidism occurred in 17.5% of patients, with a median onset at 0 months.
• No significant risk factors for HT were identified through univariate analysis, except for elevated pre-radiation thyroid-stimulating hormone levels for clinical HT.

Conclusions:

• Head and neck irradiation is associated with the development of hypothyroidism.
• Periodic thyroid function evaluation is recommended for all patients who have undergone neck radiation therapy.