Correlation Between Ultrasonographic Features Of Papillary Thyroid Microcarcinoma And Cervical Lymph Node Metastasis

Purpose: To explore the correlation between ultrasonographic features of papillary thyroid microcarcinoma(PTMC)and cervical lymph node metastasis,with the purpose of providing important ultrasonographic signs for preoperative prediction of lymph node metastasis and guiding the clinicians to deal with PTMC normally.Methods: We reviewed 710 PTMC,pathologically confirmed after operation in Tianjin Cancer Institute and Hospital;all patients were divided into cervical lymph node metastasis group and non-metastasis group.We analyzed the preoperative ultrasound images of all patients,and recorded the ultrasonic signs of each patient in detail,such as tumor size,multifocality,taller-than-wide,peripheral vascularity,tumor location,echogenicity,margin,micro-calcification,the ratio of abutment/ perimeter.We analyzed the ultrasonographic characteristics of primary site and risk factors of cervical lymph node metastasis;and summarized the ultrasonographic signs that can predict cervical lymph node metastasis before operation,provided a reliable tool for the clinician to assess the patient’s condition and determined the surgical selection.Results: Of 710 patients,in clinical features,the multifocality and capsular invasion were associated with cervical lymph node metastasis.In ultrasonographic features,the univariate analysis showed that tumor size,taller-than-wide,tumor location,hypoechogenicity,micro-calcification,margin,capsule invasion more than 1/4 perimeter of PTMC were associated with cervical lymph node metastasis(including lateral and central LNs).The multivariate Logistic analysis showed that micro-calcification,capsule invasion more than 1/4 perimeter of PTMC were independent risk factors of central lymph node metastasis;The tumor size>5mm,tumor location in the upper pole,micro-calcification and capsule invasion more than 1/4 perimeter of PTMC were independent risk factors of lateral lymph node metastasis;The tumor size>5mm,taller-than-wide,tumor location in the upper pole,capsule invasion more than 1/4 perimeter of PTMC were independent risk factors of skip metastasis of ipsilateral lymph nodes.In addition,capsule invasion more than 1/4 perimeter of PTMC was associated with the degree of extrathyroidal extension.Conclusions: The micro-calcification and capsule invasion more than 1/4 perimeter of PTMC were independent risk factors of cervical lymph node metastasis;The capsule invasion more than 1/4 perimeter of PTMC was independent risk factors of maximal extrathyroidal extension.Therefore,ultrasonographic features of primary focus had great predictive value for cervical lymph node metastasis and the degree of extrathyroidal extension,and provided important theoretical basis for clinicians to standardize the diagnosis and treatment of PTMC.