Factors Affecting the Locoregional Recurrence of Conventional Papillary Thyroid Carcinoma After Surgery: A Retrospective Analysis of 3381 Patients

Papillary thyroid carcinoma (PTC) does recur, despite its favorable long-term outcome. The incidence of thyroid cancer in South Korea increased during the 1990s, then increased rapidly after the turn of the century. In 2011, the rate of thyroid cancer diagnoses was 15 times that observed in 1993. The present study aimed to identify factors associated with the locoregional recurrence of recently increasing conventional PTC. The records of 3381 patients with conventional PTC were reviewed for this retrospective cohort study. Between January 2004 and January 2012, these patients underwent ultrasonography, computed tomography, and preoperative and total thyroidectomy with central neck dissection. Disease recurrence was defined as structural evidence of disease following the remission period. Median length of follow-up was 5.6 (range 2.1-10.1) years. Of 3381 patients, 75 (2.2 %) experienced recurrence. The univariate analysis suggested that locoregional recurrence was associated with tumor size, multifocality, extrathyroidal extension (ETE), lymph node metastasis, lymphatic invasion, vascular invasion, and positive surgical margin. However, multivariate analysis showed that only tumor size (p < 0.001), bilaterality (p < 0.001), gross ETE (p = 0.049), lymph node metastasis (p < 0.001), and vascular invasion (p = 0.013) were independently associated with locoregional recurrence. Tumor size, bilaterality, gross ETE, lymph node metastasis, and vascular invasion were associated with locoregional recurrence. Evaluation of these prognostic factors appears to help identify patients who require close monitoring.