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Radiation Hypothyroidism — SCE Medical Oncology MCQ

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EasyHead & Neck CancerRadiation HypothyroidismSCE Medical Oncology

A 60-year-old man with advanced head and neck SCC completes concurrent cisplatin-chemoradiotherapy. Three months later, he develops hypothyroidism (TSH 45 mIU/L, fT4 6 pmol/L). He is asymptomatic. What is the cause and management?

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Correct answer: E — Radiation-induced hypothyroidism — a common late effect of neck irradiation; start levothyroxine replacement

Radiation-induced hypothyroidism is the most common endocrine late effect of head and neck radiotherapy, occurring in approximately 20-50% of patients within 1-2 years of treatment. It is caused by radiation damage to the thyroid gland (which lies within the radiation field for most H&N treatments). Lifelong TSH monitoring (6-12 monthly) is recommended after head and neck radiotherapy. Levothyroxine replacement is started for overt hypothyroidism. Subclinical hypothyroidism (TSH 5-10) may be monitored initially.

Reference: NICE NG36; ESMO 2024 Head and Neck Cancer Survivorship; NICE CG Thyroid disease