Characteristics and Prognostic Factors of Recurrence after Hemithyroidectomy in Patients with Papillary Thyroid Microcarcinoma

Abstract

Background and Objectives The incidence of papillary thyroid microcarcinoma (PTMC) continues to increase worldwide. However, there is a lack of a comprehensive understanding of recurrence after hemithyroidectomy in patients with PTMC. We aimed to evaluate the characteristics and risk factors of recurrence after hemithyroidectomy in patients with PTMC.Subjects and Method We included 527 patients with PTMC who underwent hemithyroidectomy between 2009 and 2017.Results At a mean follow-up of 76.4 months after hemithyroidectomy, recurrence occurred in 4.2% (22/527) of the patients. The times of recurrence were <12, 12-24, 24-36, 36-48, 48-60, and >60 months after initial surgery in 1 (4.5%), 6 (27.3%), 5 (22.7%), 4 (18.2%), 4 (18.2%), and 2 (9.1%) patient(s), respectively. The most common recurrence site was the contralateral remaining thyroid lobe. In univariate analyses, only multifocality was demonstrated to be associated with an increased risk of recurrence [hazard ratio (HR), 2.834; confidence interval (CI), 1.044-7.693; <i>p</i>=0.041). In multivariate analyses, multifocality (HR, 2.982; CI, 1.091-8.155; <i>p</i>=0.033) and central lymph node metastasis (HR, 9.649; CI, 1.238-75.217; <i>p</i>=0.030) were demonstrated to be associated with an increased risk of recurrence.Conclusion The follow-up after hemithyroidectomy for PTMC should focus on the postoperative 1–5-year period with meticulous inspection of the remaining thyroid lobe, particularly in patients with multifocality or central lymph node metastasis.