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

Objective: To evaluate the correlation between sonographic features of primary papillary thyroid microcarcinoma(PTMC) and cervical lymph node metastasis.Methods: Preoperative sonographic features of primary papillary thyroid microcarcinoma confirmed pathologically in 287 patients were retrospectively reviewed from Jan 2010 to Dec 2014.Including the size,echo, aspect ratio(A/T), location, shape, edge, boundary, internal structure, calcification(micro calcification, coarse calcification), acoustic halo, rear attenuation, coated contact area, degree of blood supply(Adle classification) and multifocal or not,and were divided into two groups,lymph node metastasis and lymph node non-metastasis according to pathology.Analyze sensitivity, specificity, positive predictive value, and negative predictive value of preoperative ultrasonography in the diagnosis of cervical lymph node metastasis,and the difference of sonographic features between cervical lymph node metastasis group and non-metastasis group(including primary lesion maximum diameter, echo, aspect ratio, location, shape, edge etc). A Logistic model would be obtained to find primary sonographic features of cervical lymph node metastasis.P<0.05 for the difference had statistical significance.Results:(1)According to pathological results, 287 cases of PTMC with total 326 primary lesion, 86 cases with lymph node metastasis, 201 cases with lymph node non-metastasis, cervical lymph node metastasis rate was 29.97%(86/287).(2)The sensitivity of preoperative ultrasonography in the diagnosis of cervical lymph node metastasis was 16.28%(14/86),specificity was 95.52%(192/201),positive predictive value was 60.87%(14/23), and negative predictive value was 72.73%(192/264).(3) Univariate analysis revealed that gender, age, primary lesion shape, edge, micro calcification were statistically significant between lymph node metastasis group and non-metastasis group(χ2 were 7.42, 6.08, 9.69, 8.60, 7.42,all P<0.05).(4)Multivariate analysis revealed that: gender, age, primary lesion shape, coated contact area was an independent factor for PTMC patients with cervical lymph node metastasis(OR(95%CI)were2.31(1.17-4.56),0.5(0.26-0.94),2.94(1.32-6.57),1.58(1.03-2.42)),all P<0.05).Conclusion: The sensitivity of preoperative ultrasonography in the diagnosis of cervical lymph node metastasis is low. Lymph node metastasis happens relatively more common in PTMC patients with the factors such as male, age≤50 years old,irregular shape, irregular edge, micro calcification.Male, age ≤ 50 years old, primary lesion irregular in shape and coated contact area bigger are independent risk factors of cervical lymph node metastasis in PTMC,and the ultrasonic characteristics of primary lesion irregular in shape is the important index to predict neck lymph node metastasis. The primary lesion sonographic features contribute to the prediction and treatment scheme of PTMC patients with cervical lymph node metastasis.