[Evaluation of radionuclide therapy for the residue after surgery in papillary thyroid carcinoma]

To assess the efficacy of radioactive iodine (RAI) for the treatment of residual papillary thyroid cancer (PTC) after surgery.

A total of 20 patients diagnosed with PTC and underwent 2-6 courses of RAI therapy for residual PTC after surgery in other hospitals were included our study. Of these, 13 were in stage I, 3 in stage III and 4 in stage IV. All the cases were operated again due to the presence of suspicious residual tumors indicated by CT. Excision of thyroid tumor residue was performed in 5 cases and neck dissection in 15 cases (20 sides). The suspicious thyroid or neck residual tumors were examined pathologically after surgery. Response Evaluation Criteria in Solid Tumors (RECIST) was used to evaluate the efficacy of surgery treatment on residual tumor. T-test was used to identify variables associated to RAI and to calculate the propensity score to receive RAI after surgery.

The patients aged 22-58 years, with a median age of 40 years. The mean times of surgeries received before RAI was 1.5 and the mean dose of applied RAI was 318 mCi (210-660 mCi). No significant difference in tumor size between pre-RAI and post-RAI was found (t = 1.177, P > 0.05). With postoperative pathological examination, the suspicious thyroid or neck residual tumors were confirmed as PTC or the cervical lymph metastasis of PTC.

For the residue or metastasis of PTC after operation, reoperation should be a priority, while RAI therapy has no obvious therapeutic effect and it should be limited to selected cases such as those with distant metastasis or unsuitable for operation but with iodine uptake function, or taken as an adjuvant treatment after radical resection of cervical lesions.