Comparison of Thyroid examination, Thyroid scanning and sonography in patients with previous history of radiotherapy of the head for Tinea Capitis [Persian]

Introduction: In spite of large number of studies regarding relation between thyroid cancer and childhood irradiation, contraversy still exists management of these patients. This study tries to find optimal method of thyroid evaluation in this group. Methods and patients: In a recall program using mass media in Khorasan, all patients with childhood irradiation were invited for thyroid evaluation. One hundred and eighty patients with previous history of radiation for Tinea Capitis were studied using thyroid examination, thyroid sonography and thyroid scintigraphy. FNAB was performed in all patients with palpable nodules and surgery was recommended. Results: Eighty two cases out of 179 patients (45.8%) had nodules in thyroid examination. The number were 85 from 166 (51.2%) in sonography and 75 from 165 (45.5%) in thyroid scintigraphy. Using Chi-square tests, no significant difference was noted in detection of thyroid nodules in different methods (P=0.78) as well as between the methods (P>0.5). Sonographically detected nodules which were not palpated or were not seen in scintigraphy, were <10 mm in size in most of cases. FNAB were performed in 60 patients which revealed benign pathology in 89.9% inadequate in 5% and suspicious for malignancy in other 5% of cases. Also 27 patients underwent surgery and pathological studies showed 3 cases (11.1 %) of papillary carcinoma. Conclution: This study revealed that sonography detects small nonpalpable nodules which are not clinically significant. Very high correlation between the results of thyroid examination and thyroid scintigraphy indicates adequacy of thyroid examination in these patients. We suggest to follow these patients with physical examination and FNAB and use thyroid scanning or sonography in doubtful cases only.