Influence Factors Of Postoperative Thyroid Remnants And Its Relationship With 131I Effect In Differentiated Thyroid Cancer

Part 1 Influence factors of postoperative thyroid remnants in differentiated thyroid cancerObjectivesThis study aims to provide a way to estimate the volume of the thyroid remnant and determine its influence factors.Materials and MethodsA retrospective analysis was performed on patients who underwent initial RAI therapy between January 2013 and December 2016.The patients were divided into five groups based on the thyroid remnant estimated by post-therapy whole-body scan(post-Rx WBS),thyroid scintigraphy and ultrasonography.It investigated influence of each factor on the thyroid remnants by univariate analysis and multivariate logistic regression analysis.ResultsOf 1481 patients,the majority could be found different size of thyroid remnants using the three imaging methods,and only 39 patients(Group A,2.6%)could reach no thyroid remnant.422(Group B,28.5%)could be detected thyroid remnants by post-Rx WBS,667(Group C,45.0%)could be detected thyroid remnants by post-Rx WBS and thyroid scintigraphy,and 353(Group D+E,23.8%)could be detected thyroid remnants by ultrasonography.From 2014 year to 2016 year,the proportion of Group D+E decreased from 30.0%to 16.2%,and the proportion of Group C increased from 39.4%to 61.0%.There were statistical significant difference in nerve invasion,hospital grade,the number of operations and scope of lymph node dissection between the four groups.In multivariate logistic regression analysis,it showed that hospital grade and scope of lymph node dissection were independent risk factors for thyroid remnants(P=0.001,OR=2.23,95%IC:0.335-1.272;P<0.001,OR=1.90,95%IC:0.281-1.006,respectively).There were statistical significant differences in parathyroid hormone,blood calcium and thyroid-stimulating hormone(TSH)between the four groups(P=0.016,P=0.003,P<0.001).While the volume of thyroid remnant increases,the proportion of patients with parathyroid hormone less thanl.6pmol/L,blood calcium less than 2mmol/L or TSH less than 30 ? IU/ml reduces.ConclusionIn recent years,the proportion of patients with excessive postoperative thyroid remnants in DTC has decreased.The volume of thyroid remnants was affected by the surgical hospital grade and the scope of lymph node dissection,and there has nothing to do with the number of operations and pathological characteristics.Moreover,the volume of thyroid remnants affected the postoperative blood calcium,parathyroid hormone and TSH values to a certain extent.Physicians should weigh the pros and cons when removing thyroid.While reducing the amount of thyroid residual,the occurrence of adverse reactions should be minimized.Part 2 Impact Of Postoperative Thyroid Remnants On Radioiodine Therapy For Differentiated Thyroid CancerObjectivesThis study aims to determine the relationship between postoperative thyroid remnants and the outcome of radioiodine(RAI)therapy.Materials and MethodsA retrospective analysis was performed on patients who underwent initial RAI therapy between January 2010 and December 2015.The patients were divided into five groups based on the thyroid remnant estimated by post-therapy whole-body scan(post-Rx WBS),thyroid scintigraphy and ultrasonography.The relationship between the volume of thyroid remnant and the outcome of RAI therapy were evaluated by univariate analysis and multivariate analysis.ResultsOf 703 patients,the majority could be found different size of thyroid remnants using the three imaging methods,and only few patients(2.1%)could reach no thyroid remnant.There was no association between the volume of thyroid remnant and the outcome of RAI therapy in univariate analysis(?2=1.633,P=0.652)and multivariate analysis(P>0.05).In the subgroup of patients with high-risk factors,there was still no significant difference(intermediate risk subgroup:P=0.338 vs high risk subgroup:P=0.263).ConclusionDifferent sizes of thyroid remnants were left after surgery even the total thyroidectomy.However,in high radioiodine activity,the volume of thyroid remnants may not affect the outcome of RAI therapy even in patients with some high-risk factors,so the high radioiodine activities may resolve the the problem caused by thyroid remnants in some cases.