Long-term follow-up ultrasonography after lobectomy in papillary thyroid microcarcinoma patients: A single-center study.

PURPOSE: This study aimed to assess the prevalence of tumor recurrence and to determine the appropriate interval of follow-up ultrasonography (US) in papillary thyroid microcarcinoma (PTMC) patients who underwent lobectomy.

METHODS: Between January and December 2006, 137 patients underwent a lobectomy for the treatment of PTMC and at least one postoperative US follow-up examination. The postoperative follow-up US was performed by a single radiologist for all patients. Based on the follow-up US and histopathological results, tumor recurrence and nodal metastasis were determined.

RESULTS: In the 137 patients, the following diagnoses were made after lobectomy: intraglandular PTMC (n = 104), focally perithyroidal PTMC invasion within surgical margins (n = 18), nodal metastasis to the ipsilateral level VI node (n = 20), and satellite PTMC (n = 7). The patients showed differences in the number of post-operative follow-up US sessions and in the intervals of those sessions. Of the 137 patients, 135 (98.5%) exhibited no tumor recurrence on the follow-up US, whereas 2 (1.5%) exhibited tumor recurrence in the remnant thyroid gland. In these two patients with tumor recurrence, suspicious thyroid nodules were detected at the 96- and 90-month follow-up US, respectively.

CONCLUSIONS: In this study, the PTMC tumor recurrence rate was low, indicating that early post-lobectomy follow-up US in short intervals is not beneficial for detecting PTMC recurrence.