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International Journal of Endocrinology
Volume 2016 (2016), Article ID 3240727, 6 pages
http://dx.doi.org/10.1155/2016/3240727
Research Article

The Effect of Levothyroxine Discontinuation Timing on Postoperative Hypothyroidism after Hemithyroidectomy for Papillary Thyroid Microcarcinoma

1Department of General Surgery, Busan Paik Hospital, Inje University College of Medicine, Busan 614-735, Republic of Korea
2Department of Radiology, Busan Paik Hospital, Inje University College of Medicine, Busan 614-735, Republic of Korea
3Department of Otorhinolaryngology-Head and Neck Surgery, Busan Paik Hospital, Inje University College of Medicine, Busan 614-735, Republic of Korea
4Department of Pathology, Busan Paik Hospital, Inje University College of Medicine, Busan 614-735, Republic of Korea
5Department of Radiation Oncology, Busan Paik Hospital, Inje University College of Medicine, Busan 614-735, Republic of Korea

Received 8 March 2016; Revised 21 April 2016; Accepted 24 April 2016

Academic Editor: Giuseppe Damante

Copyright © 2016 Tae Kwun Ha et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. No previous studies regarding the appropriate timing of thyroid hormone discontinuation after hemithyroidectomy have been published. This study aimed to identify the appropriate timing for levothyroxine discontinuation after hemithyroidectomy among patients with papillary thyroid microcarcinoma (PTMC). Methods. This study retrospectively evaluated 304 patients who underwent ≥1 attempt to discontinue levothyroxine after hemithyroidectomy for treating PTMC between January 2008 and December 2013. Fifty-three patients were excluded because of preoperative hypothyroidism or hyperthyroidism, a history of thyroid hormone or antithyroid therapy, no available serological data, or a postoperative follow-up of <24 months. We evaluated the associations of successful levothyroxine discontinuation with patient age, sex, preoperative serological data, underlying thyroid gland histopathology, anteroposterior diameter of the residual thyroid gland, number of discontinuation attempts, and initial discontinuation timing. Results. Among the 251 included patients, 125 patients (49.8%) achieved successful levothyroxine discontinuation during the follow-up period after hemithyroidectomy. There was a significant difference in the outcomes for patients who underwent an initial discontinuation attempt at ≤3 months and ≥4 months after hemithyroidectomy (p < 0.001). There were significant differences in the discontinuation outcomes according to underlying thyroid histopathology (p = 0.001), preoperative thyroid-stimulating hormone levels (p < 0.001), and number of discontinuation attempts (p < 0.001). Conclusions. Among patients with PTMC, the initial levothyroxine discontinuation attempt is recommended at ≥4 months after hemithyroidectomy.