Predictive factors for recurrence of papillary thyroid carcinoma: analysis of 4,085 patients

Objective: The incidence of papillary thyroid carcinoma (PTC) has increased in recent years and its treatment remains controversial. The objective of this study is to identify clinicopathological predictive factors of tumour recurrence. Methods: We retrospectively analysed 4,085 patients who underwent thyroidectomy for PTC from 1996 to 2015. Patients were stratified according to American Thyroid Association (ATA) risk categories and clinicopathological features were evaluated to identify independent factors for recurrence. Results: After a mean follow-up of 58.7 (range 3-256.5) months, tumour recurrence was diagnosed in 176 (4.3%) patients, mostly in lymph nodes. Distant metastasis occurred in 18 patients (0.4%). There were 3 (0.1%) cancer-related deaths. Multivariate analysis showed that tumour size >10 mm, multifocality, extrathyroidal extension and lymph node metastasis (all, P < 0.001) were independent risk factors for recurrence. Further, recurrence was identified in 1.6% of the ATA low-risk, 7.4% of the intermediate-risk and 22.7% of the high-risk patients (P < 0.001). Conclusions: In PTC patients, tumour size >10 mm, multifocality, extrathyroidal extension and presence of lymph node metastasis as well as the ATA recurrence staging system effectively predict recurrence.