Efficacy of hemithyroidectomy in papillary thyroid carcinoma with minimal extrathyroidal extension.

PURPOSE: This study aimed to compare the oncologic outcomes of hemithyroidectomy with total thyroidectomy in clinically node-negative (cN0) papillary thyroid carcinoma (PTC) with minimal extrathyroidal extension (ETE). METHODS: Among 1826 PTC patients who underwent thyroidectomy from Jan 2001 to Dec 2014, there were 255 with unilateral cN0 PTC with minimal ETE and of equal to or less than 2 cm in size; these 255 patients were included in this study. We excluded patients who had tumor size > 2 cm, bilateral tumors, clinically positive nodes, maximal or no ETE, gross invasion of sternothyroid muscle, recurrent cancers or distant metastases. Total thyroidectomy was performed in 173 of the 255 patients, and hemithyroidectomy in 82 of them. A propensity score-matched analysis was carried out to reduce selection bias, with the following covariates: sex, age, tumor size, multiplicity and central neck dissection. RESULTS: In the baseline data of the 255 patients, female, age and tumor size were significantly higher in the total thyroidectomy group as was Stage III, whereas T and N classification did not differ in the two groups. Propensity score matching generated two matched groups of 66 patients each, in which the significant differences between the two groups seen in the baseline analysis disappeared. In the matched samples, recurrence rate (3.0% vs. 1.5%, p = 1.0) and recurrence-free survival curves did not differ between total thyroidectomy and hemithyroidectomy. CONCLUSIONS: Hemithyroidectomy can be recommended for cN0 PTC 1 cm or less with minimal ETE. Also it can be considered for cN0 PTC 11-20 mm with minimal ETE.