Impact of early vs late postoperative radioiodine remnant ablation on final outcome in patients with low‐risk well‐differentiated thyroid cancer

Postoperative radioiodine remnant ablation (RRA) represents an adjunctive therapeutic modality in patients with differentiated thyroid cancer (DTC). The impact of late vs early RRA on the outcome of DTC is currently unclear. The aim of the study was to evaluate the outcome of patients with DTC according to RRA timing.A total of 107 TNM stage 1 DTC patients were divided into two groups. In group A (n = 50), RRA was administered in less than 4·7 months median 3·0 (range 0·8-4·7), while in group B (n = 57) in more than 4·7 months median 6 (4·8-30·3) after thyroidectomy. Remission was achieved when stimulated serum Tg levels were undetectable, in the absence of local recurrence or cervical lymph node metastases on the neck ultrasound.All patients underwent near-total thyroidectomy. The mean age at diagnosis was 49·3 years (range: 18-79 years). There were no statistically significant differences in the histological subtype, the TNM stage, the dose of radioiodine and the time of follow-up, between the two groups. After the RRA treatment, 44 group A patients (88%) were in remission and 6 (12%) in persistence; while in group B, 52 (91·2%) were in remission, 1 (1·8%) in persistence and 4 (7%) in recurrence. At their latest follow-up median 87·3 (23·3-251·6 months), all patients were in remission, either as a result of further iodine radioiodine therapy (in 11 patients) or watchful monitoring.The timing of RRA seems to have no effect on the long-term outcome of the disease. Therefore, urgency for radioiodine ablation in patients with low-risk thyroid cancer is not recommended.