Comparison of Thyroid Nodule Prevalence by Ultrasound in Childhood Cancer Survivors With and Without Thyroid Radiation Exposure

Children receiving radiotherapy of the head, neck, or chest as treatment of primary malignancies are at increased risk for secondary thyroid malignancy. We hypothesized that current standards (yearly thyroid physical examination) lead to a substantial number of missed thyroid nodules. Our objectives were: (1) use thyroid ultrasound to assess thyroid nodules in childhood cancer survivors; and (2) compare prevalence of thyroid nodules in thyroid radiation-exposed patients as compared with cancer survivors without radiation exposure. We recruited 60 patients with thyroid radiation and chemotherapy exposure (median age at cancer diagnosis 10.8 y) and 59 patients with chemotherapy exposure alone (median age at diagnosis 4.3 y) from our long-term survivorship clinics. Each patient had a thyroid physical examination and thyroid ultrasound performed. Thirty-three patients (27.7%) had nodules >0.3 cm of which 2 were palpated (6.1%). We found 22 radiated patients (36.7%) with nodules versus 11 nonradiated patients (18.6%) (P=0.03). Eleven patients were biopsied and 1 diagnosis of secondary papillary thyroid carcinoma was confirmed. Our study supports further examination of incorporating thyroid ultrasounds into long-term survivorship follow-up guidelines in radiation-exposed patients for the detection of thyroid nodules and secondary malignancies.