Clinical implications of pathologic factors after thyroid lobectomy in patients with papillary thyroid carcinoma

Objective We evaluated the clinical and prognostic significance of pathologic factors by analyzing the treatment results of patients who underwent thyroid lobectomy. Materials and methods We retrospectively analyzed data from 734 patients diagnosed with papillary thyroid cancer who underwent thyroid lobectomy at Korea University Hospital from January 2004 to December 2016. Results A total of 734 patients were included in the study and their mean age was 44.5 years (range, 15–83). On univariate analysis, tumor size and recurrence-free survival were significantly related. The 10-year recurrence-free survival was 98.3% for tumors ≤1 cm, 77.8% for >1 cm and ≤2 cm, and 66.7% for >2 cm (p = 0.014). Recurrence-free survival was significantly different between patients with and without microscopic extrathyroidal extension (p = 0.002). The 10-year recurrence-free survival rate was 99.2% for patients without extrathyroidal extension and 92.2% for patients with microscopic extrathyroidal extension. Multivariate analysis showed only microscopic extrathyroidal extension was significantly correlated with recurrence-free survival (p = 0.029). Conclusion In patients undergoing thyroid lobectomy for low-risk papillary thyroid cancer, microscopic extrathyroidal extension was an important prognostic factor associated with recurrence-free survival. However, in cases with microscopic extrathyroidal extension findings on postoperative pathologic examination, appropriate ultrasonographic follow-up of the contralateral thyroid lobe and cervical lymph node to facilitate early detection and prompt treatment of recurrence can control the disease without a deterioration of survival rate.