Sonographic Features Of Papillary Thyroid Microcarcinoma Predicting High-volume Central Lymph Node Metastasis

Objective:A high number of metastatic neck lymph nodes(>5)is significantly associated with the recurrence of PTC.The aims of this study are to analyze the demographic and sonographic features of cN0 papillary thyroid microcarcinoma(PTMC)and PTMC associated with high-volume central lymph node metastasis(Hv-CLNM).Method:We retrospectively reviewed the medical records of 1648 PTMC patients and 1423 cNO-PTMC patients who underwent surgery from October 2013 to December 2015.All the patients with lymph node metastasis identified by histopathology were included.Preoperative sonographic features,such as multifocality,tumour size,echogenicity,calcification,vascularity of papillary microcarcinoma,and capsule invasion,were recorded.Univariate and multivariate analyses were performed to investigate the relationships between sonographic features and high-volume central lymph node metastasis(number of metastatic lymph nodes>5).Results:Among the 1648 PTMC patients,73 patients(4.4%)had high-volume central lymph node metastasis.Multiple logistic regression analysis showed The following features including age<45 years old(OR=2.704,p<0.001),male sex(OR=2.631,p<0.001),the preoperative ultrasonic features of microcalcifications(OR=2.300,p=0.009),larger tumour size(>7 mm)(OR=2.157,p=0.003)and suspicious central lymph node(OR=6.174,p<0.001)were independent risk factors for high-volume central lymph node metastasis in the central compartment of PTMC.Among the 1423 cNO-PTMC patients,37 cases(2.6%)have high volume LNM.The following features including age<45 years old(OR=3.674,p=0.001),male sex(OR=2.494,p=0.008),larger tumor size(>7mm)(OR=2.666,p<0.001)were independent risk factors of cNO PTMC for high volume CLNM.Conclusion:Several risk factors of PTMC may associated with high volume CLNM.As these features appear,the aggressive approach and careful follow-up are necessary to prevent PTMC recurrence.