[A comparative analysis of hemithyroidectomy and total thyroidectomy in sporadic medullary thyroid carcinoma]

Objective: To compare the therapeutic effects of hemithyroidectomy (HT) versus total thyroidectomy (TT) on sporadic medullary thyroid carcinoma (sMTC). Methods: Clinical data of sMTC patients firstly treated in Tianjin Medical University Cancer Institute and Hospital from January 2011 to December 2019 were reviewed retrospectively. The patients were categorized into the HT group and the TT group based on the extents of primary tumor resection. The differences in clinical characteristics between the two groups were compared. A 1∶1 matching of variables including tumor stage and mulifocality was performed using propensity score matching (PSM) to balance the baseline differences between the two groups. Subsequently, the differences in biochemical cure rate, biochemical recurrence rate, and structural recurrence rate between the two groups were compared. Survival curves were plotted using the Kaplan-Meier method, and the log-rank test was utilized to compare the differences in progression-free survival and overall survival between the two groups. Results: A total of 199 patients with sMTC were included in the study, comprising 80 males and 119 females, with the age [M(Q₁,Q₃)] of 51.0 (42.0,59.0) years. Before PSM, 117 patients were in HT group and 82 patients were in TT group. There were statistically significant differences in preoperative calcitonin, N stage, TNM stage, and the number of lesions between the two groups (all P<0.05). After PSM, 63 patients were in HT group and 63 patients were in TT group. There was no statistically significant difference in all clinicopathological characteristics between the two groups (all P>0.05). Before PSM, the biochemical cure rate in the HT group was higher than that in the TT group [76.4% (81/106) vs 60.5% (46/76), P=0.021]. There were no statistically significant differences in the biochemical recurrence rate and structural recurrence rate between the HT group and the TT group [4.7% (5/106) vs 7.9% (6/76), 8.5% (10/117) vs 15.9% (13/82), both P>0.05]. The progression-free survival of the HT group was longer than that of the TT group [(137.26±3.53) vs (114.12±5.98) months, P=0.025]. There was no statistically significant difference in overall survival between the HT group and the TT group [(142.12±2.91) vs (126.92±5.15) months, P=0.140]. After PSM, there were no statistically significant differences between the HT group and the TT group in terms of biochemical cure rate [66.7% (40/60) vs 77.2% (44/57)], biochemical recurrence rate [5.0% (3/60) vs 7.0% (4/57)], structural recurrence rate [12.7% (8/63) vs 17.5% (11/63)], progression-free survival [(130.69±5.07) vs (112.19±6.91) months], and overall survival [(136.05±4.04) vs (124.71±6.83) months] (all P>0.05). Conclusions: The therapeutic effects of HT and TT on sMTC are comparable. With careful preoperative evaluation, selective performance of HT is safe and feasible.