The Correlation Between Lateral Compartment Lymph Node Metastasis Of Patients With Papillary Thyroid Carcinoma And Clinicopathological Characteristics And The Evaluation Of Potential Diagnostic Role

Objective To analyze the relevant factors of lateral compartment lymph node metastasis and their potential diagnostic role in papillary thyroid carcinoma(PTC) and generalize clinical application of a selected neck dissection through a low-collar incision in PTC.Method We retrospectively analyzed clinicopathological data of 357 PTC cases with no definite enlarged lymph nodes detected by clinical physical examination (CN-) or imaging tests before surgery who underwent total thyroidectomy with a selected neck dissection through a low-collar incision and 78 PTC cases who underwent functional cervical dissection through L-form incision in General Surgery Department of Nan Jing Drum Tower Hospital affiliated to Medical College of Nanjing University from 2009.1 to 2014.12. The extent of lymph node dissection ranged over central compartment、Ⅱ a、Ⅲ、Ⅳ and Ⅴ b at least.The correlation between side、gender、age、primary tumor size、extra-thyroid invasion、cervical lymph node size、central compartment lymph node、mulifocality and lymph node grit calcification or strong echo and lateral compartment lymph node metastases were analyzed by Chi-Square test or Fisher test. The influence degree was expressed as degree of variance interpretation by principal component analysis (PCA).Sensitivity、specificity、positive predictive value (PPV)、negative predictive value (NPV) were setted for assessing diagnostic ability of each clinicopathological characteristic and the number of clinicopathological characteristic. Youden Index (YI) and receiver operating characteristic curve (ROC) were used to evaluate the discriminatory ability of a test. There was significantly difference when P<0.05.The surgical method of a selected neck dissection through a low-collar incision was compared with functional cervical dissection through L-form incision in ength of incision、operative time、hospitalization period、the number of dissected lymph nodes and postoperative complications. There was significantly difference when P<0.05.Results In 357 CN- cases, metastatic rate of lymph node in neck central area was 68.91%(246cases)while the lateral compartment was 57.98%(207cases) and skipping metastasis was 7.56%(27cases). No cases appeared hoarseness、postoperative massive hemorrhage or relapse. Smaller incision (6.5±1.40 vs 13.9±2.33cm)、 shorter surgery time (172.9±41.60 vs 257.3±67.59min)、shorter total hospitalization period(6.7±3.71 vs 7.3±1.67d)、minimal trauma (1.68%vs15.38%)、 more cosmetic (6.16%vs46.15%) were the advantages of a selected neck dissection through a low-collar incision compared with functional neck dissection by "L" incision (P<0.05), but the results showed no differences in incidence of common complications (chylous fistulal.87%vs5.13%、acalcicosis22.67% vs28.21%)、 number of dissected total lymph nodes (15.7±7.98 vs 14.7±6.95) or lateral compartment lymph node (10.1±6.58 vs 9.9±5.82) and recurrence rate (0.0%vs0.0%) (P>0.05).It showed significantly difference between age、primary tumor size、extra-thyroid invasion、cervical lymph node size、central compartment lymph node、mulifocality and lymph node grit calcification or strong echo and lateral compartment lymph node metastases(P<0.05), but not in gender and side (P> 0.05)A diagnostic standard was established from these clinicopathological characteristics including age<45years、larger or equal to 1.15 centimeter in max ultrasound diameter、 extra-thyroid invasion、larger or equal to 1.05 centimeter in cervical lymph node size、 central compartment lymph node metastasis、mulifocality and lymph node grit calcification or strong echo. Both larger or equal to 1.05 centimeter in cervical lymph node size and central compartment lymph node metastasis showed the most significant impact on lateral compartment lymph node metastasis. The degree of variance interpretation was 27.58% and 19.25%. In each associative clinicopathological characteristic, the characteristic of central compartment lymph node metastasis showed better diagnostic value (YI=42.96%).With the number of associative clinicopathological characteristic increased, metastatic rate of lymph node in lateral compartment and the NPV became more higher while the PPV became more lower. The AUC was favorable (0.81071). At least four associative clinicopathological characteristic were revealed to be the optimal diagnostic value on the number of associative clinicopathological characteristic based on the YI and ROC curve(YI=46.73% and slope=1.18863).Conclusion In thyroid carcinoma patients, especially for the CN-patients who were younger than 45 years old、larger or equal to 1.15 centimeter in primary tumor size、neck central area metastasis、mulifocality、larger or equal to 1.05 centimeter in cervical lymph node size、capsular invasion and lymph node grit calcification or strong echo, if he or she had four associative clinicopathological characteristic of all seven at least, it was suggested to take lateral compartment lymph nodes dissection. If needed, a selective cervical node dissection through a low-collar incision was a safe and reasonable choice.