Benefits and harms of hemithyroidectomy, total or near total thyroidectomy in 1-4cm differentiated thyroid cancer.

OBJECTIVE For 1-4cm differentiated thyroid cancer (DTC), current ATA guideline recommended hemithyroidectomy (HT) as an acceptable alternative initial procedure to total or near total thyroidectomy (TT). The aim of this study was to evaluate benefits and harms of HT, TT in 1-4cm DTC. METHODS In this retrospective cohort study, DTC patients who underwent initial thyroidectomy in a tertiary medical center were included. The structural persistent/ recurrent disease, reoperation rates, and surgical complications were compared using Cox proportional regression and logistic regression. Propensity score matching was performed to adjust for related clinicopathological variables. RESULTS Among 1824 DTC patients, 795 patients sized 1-4cm were included. 286 patients underwent HT and 509 patients underwent TT. In the matched analysis, no significant difference in disease-free survival (DFS) between HT and TT was observed during the median follow-up period of 56.5 months (hazard ratio [HR] 0.86; 95%CI, 0.37-2.00; p=0.733). The difference in DFS between two groups was consistent regardless of age, sex, tumor size, follow-up duration. Meanwhile, HT was associated with a decreased risk of surgical complications (odds ratio [OR] 0.47, 95% CI 0.31-0.71, p<0.001), as well as lower proportion of levothyroxine replacement (p=0.007). 2 cases in HT group received reoperation. Further multivariate analysis showed surgical procedure was not associated with structural persistence/recurrence (HR 0.68; 95%CI, 0.29-1.58, p=0.367). CONCLUSION For patients with 1-4 cm DTC without clinical evidence of lymph node metastasis or extrathyroidal extension, HT was associated with lower risk of surgical complications than TT while provided similar benefits as TT.