ObjectiveTo explore the best timing of thyroid stimulating hormone (TSH) inhibition therapy by analyzing the trend of TSH level changes after unilateral thyroid lobectomy in patients with low-risk papillary thyroid microcarcinoma (PTMC).MethodsThe clinical data of patients with low-risk PTMC who underwent unilateral thyroid lobectomy in the Dongfeng Hospital Affiliated to Hubei Medical College from September 2016 to December 2018 were retrospectively analyzed. The TSH of all patients were measured before operation and in month 1, 3, and 6 after operation, respectively, and the change trend was analyzed.ResultsAccording to the inclusion and exclusion criteria, a total of 271 patients with low-risk PTMC were included in this study. The TSH level in month 1 after operation was higher than that of before operation [(2.93±1.09) mU/L versus (2.05±0.76) mU/L, t=19.9, P<0.001]. Among the 129 patients with TSHlevel ≤2.0 mU/L before operation, 56.6% (73/129) of them still had the TSH level ≤2.0 mU/L in month 1 after operation, 45.0% (58/129) in month 3 after operation and 39.5% (51/129) in month 6 after operation.ConclusionsTSH level of patient with low-risk PTMC is increased after lobectomy, so individualized TSH inhibition treatment should be formulated. For patients with TSH level>2.0 mU/L before operation, oral levothyroxine sodium tablets should be taken immediately after operation. For patients with preoperative TSH level ≤2.0 mU/L, TSH level should be dynamically monitored, and whether and when to start oral TSH inhibition therapy should be decided according to results of TSH level.