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 ≤1cm, 77.8% for >1cm and ≤2cm, and 66.7% for >2cm (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.