Is surgical resection without radioactive iodine treatment a safe alternative treatment for T1–2N1bM0 papillary thyroid carcinoma?

Abstract Objective Postoperative radioactive iodine (RAI) adjuvant therapy improves the prognosis in patients with advanced papillary thyroid carcinoma (PTC), although the role of RAI adjuvant therapy remains unclear in intermediate-risk patients, as defined by the American Thyroid Association. The ATA cautiously recommended RAI adjuvant therapy in patients with T1–3N1b, but the Japanese Society of Thyroid Surgery suggests lobectomy without RAI adjuvant therapy in these patients. This study assessed the role and efficacy of RAI adjuvant therapy in patients with T1–3N1b PTC. Methods A single-center retrospective observational study was performed. We included patients with T1–3N1bM0 PTC who underwent complete resection between January 2003 and December 2017. Patients with bilateral PTC were excluded. We compared recurrence rates after surgery with RAI adjuvant therapy and surgery alone. Results A total of 61 patients (male:female ratio, 18:43; mean age, 57.1 ± 16.7 years) were included, and the median follow-up period was 6.8 years. Of the included patients, 33 were treated with surgery with RAI adjuvant therapy and 28 were treated with surgery alone. The RAI treatment group that underwent surgery had larger tumors, more lymph node metastases, and were younger. There were no disease-specific deaths, and 10 patients experienced local recurrence. The recurrence rate was 24.2% in patients who underwent surgery with RAI adjuvant therapy and 7.1% in patients who underwent surgery alone. Compared to T1–2 stage patients, the T3 stage patients tended to have a higher recurrence rate (odds ratio, 2.38; 95% confidence interval, 0.51–10.7). Conclusions The recurrence rate was higher in patients who underwent surgery with RAI adjuvant therapy than in patients who underwent surgery alone. Patients in the former group had larger tumors and more lymph node metastases, and this difference in baseline characteristics could explain their higher recurrence rate. The recurrence rate was lower in patients with small tumors, and RAI adjuvant therapy would likely not play a major role in T1–2N1bM0 patients.