Comparison of Lobectomy and Total Thyroidectomy in Unilateral Papillary Thyroid Microcarcinoma Patients with Ipsilateral Lateral Lymph Node Metastasis Without Gross Extrathyroidal Extension.

Background: Lateral lymph node metastasis (LLNM) occurs in a few of papillary thyroid microcarcinoma (PTMC) cases by the time of diagnosis. Total thyroidectomy (TT) is recommended in the 2015 American Thyroid Association guidelines as the initial surgical procedure for thyroid carcinoma patients with clinically apparent cervical lymph node metastasis. However, none of the controlled studies have focused on the proper extent of surgery for patients who have PTMC with concomitant LLNM without gross extrathyroidal extension (ETE).

Methods: A total of 2373 consecutive patients with PTMC were retrospectively reviewed. Finally, 129 unilateral PTMC patients with ipsilateral LLNM without gross ETE were enrolled in this study and classified into two groups: those who underwent unilateral lobectomy (LT) plus lymph node dissection (LND) (Group I) and those who underwent TT plus LND (Group II). Surgical outcomes and recurrence-free survival (RFS) during the follow-up period were compared between the two groups.

Results: There were 62 patients in Group I and 67 patients in Group II. Cases in Group II had a longer median operation time (150 min vs. 120 min, p < 0.001) and a higher incidence of postoperative hypoparathyroidism (p < 0.001), especially permanent hypoparathyroidism, than cases in Group I. But the RFS showed no statistically significant difference (p = 0.6005) between the two groups during a median follow-up period of 60 months.

Conclusion: Thyroid LT alone plus ipsilateral LND may be an optimum initial procedure for unilateral PTMC patients with ipsilateral LLNM without gross ETE. A long-term follow-up, prospective, randomized controlled trial is warranted.