Thyroid nodular disease after radiotherapy to the neck for childhood Hodgkin's disease

Patients who receive radiotherapy to the neck are at risk of developing thy roid dysfunction, This prospective study of patients whose treatment for Ho dgkin's disease in childhood included radiotherapy to the neck aimed to inv estigate the incidence and natural history of thyroid dysfunction and the m orphological changes of the gland demonstrated on ultrasound. Forty-seven p atients were investigated by clinical examination, thyroid function tests a nd thyroid ultrasound. Only six patients had a clinically detectable abnorm ality, but 64% had abnormal thyroid function tests. All patients had an abn ormal thyroid ultrasound scan and 42% had at least one focal abnormality. A significant association was found between the presence of a focal lesion o n ultrasound and young age at radiotherapy longer follow-up and the length of time that the thyroid-stimulating hormone (TSH) level had been elevated. During follow-up, 65% of patients not on thyroxine developed new focal abn ormalities. The longest time interval between radiotherapy and an increase in TSH level was 94 months, and from radiotherapy to the appearance of a fo cal abnormality on thyroid ultrasound was over 18 years. Three patients wer e found to have a thyroid carcinoma. These findings indicate the importance of long-term follow-up for patients treated by neck irradiation for Hodgki n's disease in childhood.