Role of adjuvant therapy with radioactive iodine in patients with elevated serum thyroglobulin after neck reoperation due to recurrent papillary thyroid cancer: a monoinstitutional comparative study

Background Most patients with papillary thyroid cancer (PTC) and lymph node metastases (LNM) undergoing reoperation do not show apparent disease after this procedure, but serum thyroglobulin (Tg) continues to be elevated in part of them. This study evaluated adjuvant therapy with I-131 in these patients. Methods Patients with PTC and LNM diagnosed after initial therapy were selected. Patients undergoing reoperation and those without apparent disease after this procedure, but with nonstimulated Tg >= 1 ng/ml 6 months after reoperation, were included. The first 25 patients were submitted to therapy with I-131 (groups A) and the subsequent 30 patients did not receive this therapy (group B). Results Groups A and B were similar. During further follow-up, 21 patients developed structural disease and 34 continued without detectable disease (eight achieved complete remission). The outcomes were similar in groups A and B. Patients with Tg reduction >50% after reoperation tended to have a lower risk of recurrence (22.7 versus 48.5%), notably distant metastases (0 versus 15.1%), and were more likely to achieve complete remission (28 versus 3%). Patients with LNM FDG-positive had a higher risk of recurrence (54.5 versus 11.7%) and were less likely to achieve complete remission (3 versus 29.4%) after reoperation. Conclusion Our results suggest that therapy with I-131 apparently does not prevent recurrences among patients who continue to have elevated Tg after neck reoperation. Further studies involving these patients are necessary, especially those who are at high risk of recurrence.