Related Factors Of "Taller-than-wide Sign" In Papillary Thyroid Microcarcinoma And Preliminary Study In Active Surveillance

BackgroundPapillary thyroid microcarcinoma(PTMC)is a papillary carcinoma of the thyroid tumor diameter not more than 10 mm,which accounted for a large proportion in the papillary thyroid,and the incidence rate soared.There were much controversies about PTMC in progression and prognosis: Some experts hold the view that most of PTMC grows slowly with small size,and the vast majority have good prognosis.They could be a kind of inert tumor.And the incidence of thyroid cancer soared up is due to the high defect-discovery rates.Meanwhile,research based on SEER shows that the mortality rate did not increase with the incidence rate increased.So they suggestion active surveillance is enough for low risk patients.Small as the PTMC is,others believe,it does not mean at early stage.Cervical lymph node metastasis rate of PTMC can be as high as 1/3,and part of the lymph node metastasis can not be effectively found by routine examination.Then,it is indisputable that there are certain mortality rate in PTMC follow-up.What is more,active surveillance may not be able to accurately assess the progress of the disease.If significant disease progression is found before active treatment measures are taken,there would be a greater medical and ethical risk.The substance of the above debate reflects some of the dilemmasfacing the current diagnosis and treatment of PTMC.(1)There is no effective means to screen the very small number of PTMCs with poorer outcome from all PTMCs in order to early diagnosis and improve prognosis;2 The mechanism of early cervical lymph node metastasis in PTMC is unclear,and the prognostic significance is not clear.Previous studies have shown that the A/T ? 1 has higher sensitivity and specificity in the diagnosis of papillary thyroid carcinoma,especially thyroid micropapillary carcinoma.However,the previous hypothesis is difficult to explain all the phenomena.It is also unclear whether the A/T? 1 reflects the specific biological behavior of PTMC.ObjectiveBy collecting the clinicopathological data and other relevant data of PTMC patients,the factors may related to the aspect ratio ? 1 were analyzed.And the clinical significance in active surveillance was initially discussed.Methods215 patients with single papillary thyroid microcarcinoma and without another space occupying lesion who were received first surgery and diagnosed pathologically in the First Affiliated Hospital of Zhengzhou University from December 2014 to June2016 were included in this study.Color Doppler ultrasonography were carried out to evaluat “taller-than-wide sign”.The A/T?1 was used as the experimental group,and the others as the control group.And the date from clinical pathological characteristics,thyroid function,liver function,blood glucose and lipid test,BRAF V600 E mutation gene test and TNM stages were also collected for analysis.Further analysis of the correlation between tumor progression and aspect ratio ? 1 was performed in 22 patients with complete data for preoperative active surveillance.ResultThe different in TSH level,solid nodules,no blood flow signal,clear boundary and echo homogeneity was were statistically significant(P< 0.05)between the“taller-than-wide sign” group and those in control group.The different of TSH level between older group and and control group is significant difference.(P=0.006).No blood flow signal,solid nodules and high TSH are independent risk factors of A/T?1in PTMC.The optimal cutoff point of TSH is 2.465?IU/mL by ROC curve,,which showed a statistically difference(P = 0.045)in capsular invasion between two group.In the active surveillance period before surgery,the difference in tumor progression between the A/T ? 1 group and the control group was statistically significant(P = 0.01).Conclusion1.The A/T ? 1 of PTMC nodules is associated with high serum TSH,solid nodules,no intra-nodal blood flow signal.This may reflect that high serum thyroid stimulating hormone promotes the growth of PTMC toward blood-rich thyroid capsule,and the increase of blood flow signal within the nodule may affect the nodules shape by changing the local blood flow distribution of PTMC.2.The A/T ? 1 of PTMC nodules may be associated with tumor progression during active surveillance.