Hypothyroidism in patients treated with radiotherapy for head and neck carcinoma: standardised long-term follow-up study.

Objective:Hypothyroidism is a common complication when radiotherapy is part of the treatment for head and neck tumours. This study aimed to show the incidence of hypothyroidism and possible risk factors in these patients.Methods:Factors related to the population, tumour, treatment and occurrence of hypothyroidism were analysed in 241 patients diagnosed with head and neck carcinoma.Results:Approximately 53 per cent of patients were diagnosed with radiation-induced hypothyroidism. Its occurrence was related to: tumour location, laryngeal surgery type, neck dissection type, post-operative complications, cervical radiotherapy and radiotherapy unit type (linear particle accelerator or telecobalt therapy technology).Conclusion:Control of thyroid function should be standardised for several years after treatment, particularly in patients with risk factors, such as those treated with telecobalt therapy, those with post-operative complications and for whom the thyroid parenchyma is included in the irradiated area (laryngeal or pharyngeal location and bilateral cervical radiation). [ABSTRACT FROM AUTHOR]