Prospective serum thyroglobulin measurements in assessing the risk of developing thyroid nodules in patients exposed to childhood neck irradiation.

We examined 327 patients with a history of cervical radiation treatment for benign conditions and followed them for an average of 5.6 yr. These patients were selected because they initially had normal examinations and normal serum thyroglobulin levels. Of the 327 patients, 48 developed thyroid nodules, and an additional 30 had other clinical changes in their thyroids. Serum thyroglobulin increased by 4.0 +/- 0.6 (+/- SEM) ng/ml in those who remained normal, by 13.4 +/- 5.2 ng/ml in those who were no longer normal, and by 17.1 +/- 8.2 ng/ml in those who developed nodules. We conclude that increasing levels of serum thyroglobulin identify patients who should be examined and followed more carefully for thyroid nodules and thyroid cancer.