Construction and verification of lymph node metastasis model of cN0 stage thyroid micropapillary carcinoma and discussion of surgical methods

Objective:To construct and verify a model of lymph node metastasis in cN0 stage thyroid micropapillary carcinoma. To explore the significance of thyroid gland lobectomy combined with prophylactic zone Ⅵ lymph node dissection in cN0 stage thyroid micropapillary carcinoma surgery. Methods:The clinical data of 670 patients with cN0 stage thyroid micropapillary carcinoma and area Ⅵ lymph node dissection were collected. All patients underwent the affected thyroid gland lobe±isthmus resection+ area Ⅵ lymphadenectomy on the same side. Logistic regression model was constructed by gender, age, size of thyroid papillary carcinoma, whether it was multifocal, whether it was encroaching on the membrane, and whether the lymph nodes in the central area were metastasized, and displayed by nomogram. Discrimination and prediction accuracy were evaluated by C-index, calibration curve and ROC curve. An internal validation group was used to test the fitted model. Analyze the lymph node metastasis trend according to the largest tumor diameter. Follow-up analysis of the reoperation was conducted to evaluate the effect of initial surgery. Results:The rate of lymph node metastasis in area Ⅵ was 36.7%. Multiple regression analysis included three variables. The largest tumor diameter（P<0.001）, male（P<0.001） and young（P<0.001） were the main independent risk factors for lymph node metastasis. Conclusion:The reoperation rate of thyroid gland lobectomy combined with prophylactic zone Ⅵ lymph node dissection was low, and this surgical method might be safe and reliable for the treatment of cN0 stage thyroid micropapillary carcinoma, and it is worthy of promotion.