A Meta-analysis On The Treatment Efficacy Between Thyroid Lobectomy Versus Total Thyroidectomy With Differentiated Thyroid Carcinoma Sized≤4cm

Aims:Differentiated thyroid carcinoma（DTC）mainly includes papillary thyroid carcinoma（PTC）and follicular thyroid carcinoma（FTC）.Surgery is the main treatment of DTC,which includes total thyroidectomy（TT）,near total thyroidectomy（NTT）and thyroid lobectomy（TL）.The choose of initial surgical methods can lead to different results.whether there is overtreatment in TT,and what are the advantages of TL.There has been controversy as to whether all patients with DTC need to undergo TT instead of TL,for initial surgical treatment.Therefore,the meta-analysis was carried out by using the updated research data to comprehensively evaluate the impact of different initial surgical procedures on DTC,further to provide some instruction and reference for clinical practice.Methods:The related literatures were searched systematically through the databases,such as Pub Med,Embase and Cochrane Library.Literatures have been focused on the therapeutic effect between TL and TT in DTC patients sized≤4cm,and references were published before 6^th December 2020 were searched.All selected retrospective studies were evaluated according to the Newcastel-Ottawa Scale（NOS）method,which is a literature quality evaluation scale.Then,the data from reported studies were statistically analyzed by using Review Manager 5.4（Rev Man 5.4）software.The statistical results of meta-analysis were illustrated using forest map,the relative risk ratio（RR）was considered as combined effect in this study.In regards to the subgroup analysis,which were adopted to explore the sources of heterogeneity,the funnel map was utilized to evaluate publication bias.The main meta-analysis index presented in this study,including overall recurrence rate（ORR）,5 years and 10 years disease-free survival（DFS）,5 years and 10years recurrence-free survival（RFS）and postoperative complications（recurrent laryngeal nerve injury（RLNI）and hypoparathyroidism（HP））.Results:A total of 15 studies were selected,with 85702 participants,2 Chinese studies and 13 oversea studies.The ages of all subjects ranged from 4 to 91 years old.The overall quality evaluation included in the study is moderate.The results showed that there was no significant difference in overall recurrence rate,5 years disease-free survival,10 years disease-free survival and 5 years recurrence-free survival between TL group and TT group in DTC patients with sized≤4cm.RR with its 95%confidence interval（CI）were 1.29（1.00,1.65）,0.97（0.93,1.02）,0.86（0.70,1.06）,1.00（0.99,1.00）,respectively.The results of heterogeneity were as follows:I²=47%,42%,88%,0%,respectively.,The 10 years recurrence-free survival in TL group was lower than that in TT group,RR and 95%CI were 0.94（0.91,0.97）,respectively,and the result of heterogeneity was I²=18%.However,in DTC patients with sized≤4cm,the incidence of postoperative complications of recurrent laryngeal nerve injury and hypoparathyroidism in the TL group was lower than that in the TT group,and the total incidence of recurrent laryngeal nerve injury was 0.5%and 2.6%,respectively.The total incidence of hypoparathyroidism was 0.3%and 12.4%,respectively.The results of subgroup analysis showed that in the 0-1cm subgroup,there was no significant difference in overall recurrence rate and 5 years disease-free survival between the TL group and TT group.RR and its 95%CI were 1.40（0.94,2.09）and 0.93（0.87,1.06）,respectively.The result of heterogeneity was:I²=52%,0%.In the subgroup with sized 1-4cm,the overall recurrence rate in the TL group was higher than that in the TT group,and the RR and95%CI were 1.55（1.26,1.09）,The results of heterogeneity were I²=0%,there was no significant difference in 10 years disease-free survival between TL group and TT group,RR and 95%CI were 0.89（0.67,1.18）,and the results of heterogeneity was I²=90%.Conclusions:This study suggests that low-risk DTC patients with 0-1cm need only TL,TT,NTT or TL is feasible for DTC patients sized 1-4cm,for some low-risk DTC patients,TL can be performed according to the location of the tumour.Since all the studies included are retrospective,it is necessary to be cautious in interpreting the experimental results,and a larger sample of prospective studies is needed to explore the best surgical options for patients with DTC.