Ultrasound-Detected Thyroid Nodules in Radiation-Exposed Patients: Changes Over Time

The relationship between radiation exposure and thyroid cancer is well known, but whether all irradiated patients should have thyroid ultrasounds is unresolved. We have performed follow-up ultrasound examinations of patients in a cohort who were exposed to conventional external radiation during 1939–63 for benign conditions of the head and neck area prior to their 16th birthday. Of 54 subjects who had normal radionuclide scans in 1974–76 and were reexamined in 1996–97 by thyroid ultrasonography, 42 remained eligible and 34 agreed to participate in the present ultrasound study. After an additional 4–8 years of follow-up and using an ultrasound machine with increased resolution, we found 160 nodules (in 33 of these 34 subjects), compared with 96 nodules (in 29 of the 34 subjects) detected in the previous examination. Only four of the new nodules were ≥10 mm. Of the previously diagnosed large (≥10 mm) nodules, four nodules in four subjects resolved; nine nodules in six subjects regressed to <10 mm; 14 nodule...