A comparison of lobectomy and total thyroidectomy in patients with papillary thyroid microcarcinoma: a retrospective individual risk factor-matched cohort study.

OBJECTIVE: Papillary thyroid microcarcinoma (PTMC) accounts for most of the increase in thyroid cancer in recent decades. We compared clinical outcomes and surgical complications of lobectomy and total thyroidectomy (TT) in PTMC patients.

DESIGN AND METHODS: In this retrospective individual risk factor-matched cohort study, 2031 patients with PTMC were initially included. Patients who underwent lobectomy or TT were one-to-one matched according to individual risk factors, including age, sex, primary tumor size, extrathyroidal extension, multifocality and cervical lymph node (LN) metastasis.

RESULTS: In total, 688 patients were assigned to each group. During the median 8.5 years of follow-up, 26 patients (3.8%) in the lobectomy group and 11 patients (1.6%) in the TT group had recurrences. The relative risk of recurrence was significantly less in the TT than that in the lobectomy group (hazard ratio (HR) 0.41; 95% confidence interval (CI) 0.21-0.81; P = 0.01). Most recurrences (84.6%) in the lobectomy group occurred in the contralateral lobe, and all patients were disease-free after completion of thyroidectomy. There were no significant differences in recurrence-free survival between the two groups after exclusion of contralateral lobe recurrences (HR, 2.75; 95% CI, 0.08-8.79; P = 0.08). There were significantly more patients with transient and permanent hypoparathyroidism in the TT than that in the lobectomy group (P < 0.001).

CONCLUSIONS: Lobectomy could be appropriate for most patients with PTMC when there is no evidence of extrathyroidal disease in the preoperative work-up. Preoperative and postoperative imaging studies are important for patients who undergo lobectomy for PTMC, because most recurrences are in the contralateral lobe.