Radiation-related thyroid carcinoma

Of 1,825 subjects with a history of head or neck irradiation, 358 (19.6%) were found to have thyroid abnormalities. One hundred sixty-five (9%) had either single or multiple nodules 153 (8.4%) had diffuse thyromegaly, and 40 (2.2%) had had thyroid surgery. Surgery was performed on 113 subjects with nodules; carcinoma was found in 34 (30.1%). Clinical examination of the neck was the most valuable method of detecting abnormalities. Detection of nodules was not significantly enhanced by routine use of thyroid imaging studies. Measurements of levels of serum thyroid-stimulating hormone, thyroxine, triidothyronine resin uptake, and thyroid antibodies were not useful in screening for nodules or carcinoma.