Completion thyroidectomy may not be required for papillary thyroid carcinoma with multifocality, lymphovascular invasion, extrathyroidal extension to the strap muscles, or five or more central lymph node micrometastasis

This study aimed to determine whether completion thyroidectomy is necessary based on long-term follow-up oncological results according to various clinical and pathological characteristics of patients with papillary thyroid carcinoma (PTC) who underwent lobectomy.We enrolled 1815 patients with PTC who underwent thyroid lobectomy from January 2003 to December 2014. Various clinical and pathological characteristics were reviewed retrospectively, and clinicopathologic characteristics and recurrence rates were analyzed.Eighty-two (4.5%) patients showed locoregional recurrence during the average 10.2-year follow-up period. There was no significant difference in tumor size, multifocality, lymphovascular invasion (LVI), microscopic or strap muscle-extrathyroidal extension, and central neck lymph node (LN) micrometastasis between the recurrence and non-recurrence groups. The gross strap muscle-extrathyroidal extension group was associated with older age (p < 0.001), larger tumor size (p < 0.001), more capsular invasion (p < 0.001), and more LVI (p < 0.001) than the negative extrathyroidal extension group; there was no significant difference in recurrence between the groups (p = 0.096). Patients with five or more central LN micrometastases were associated with younger age (p = 0.006), larger tumor size (p = 0.04), and presence of LVI (p = 0.033) than patients with less than five central LN metastases; there was no significant difference in recurrence between the groups (p = 0.867). All patients with recurrence were cured through reoperation after recurrence was confirmed.After thyroid lobectomy, PTC patients with multifocality, LVI, extrathyroidal extension to the strap muscles, or five or more central LN micrometastases may not require immediate completion thyroidectomy.