The risk of recurrence within the first five years is very low in patients with papillary thyroid carcinoma treated with radioiodine

ABSTRACT

Introduction: In older studies, the frequency of recurrence was approximately 20% among patients with papillary thyroid carcinoma (PTC) treated with radioactive iodine (RAI), but it is possible that many of these cases actually correspond to persistent disease and that the frequency of recurrence is overestimated. Objective: To reevaluate the frequency of recurrence within the first five years in patients with PTC adequately operated upon and treated with RAI who did not exhibit persistent disease (postoperative ultrasonography and post-therapy whole-body scanning showing no apparent tumor). Methods: We selected 293 patients [51 low risk (17.4%) and 242 intermediate risk (82.6%)] submitted to thyroidectomy followed by RAI who did not have persistent disease. Results: Five years after RAI therapy, a tumor was detected in 10 patients (3.4%) (lymph node metastases in seven, pulmonary metastases in two, and bone metastases in one). Structural recurrence was observed in only 2% of low-risk patients and in 3.3% of intermediate-risk patients, with disease progression in none of the low-risk patients and in only one (0.4%) of the intermediate-risk patients. Survival was 100%. Conclusion: The results of this study suggest that, after adequate total thyroidectomy and in the absence of persistent disease, the frequency of recurrence within the first five years is very low in patients with PTC (not high risk) treated with RAI.