Study on the Influencing Factors of Cervical Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

Objective:To investigate the influencing factors of the cervical lymph node metastasis in papillary thyroid microcarcinoma(PTMC)and to provide a theoretical basis for cervical lymph node dissection.Methods:A total of 80 PTMC patients treated in the Department of Breast and Thyroid Surgery of our Hospital from January 2017 to January 2018 were selected in the study.All the patients accepted the first surgical treatment and were confirmed by pathology.The clinical data of all PTMC patients were retrospectively analyzed,and the related factors such as gender,age,number of primary lesions,tumor diameter and extrathyroidal invasions were analyzed.The factors that actually affected the lymph node metastasis of PTMC patients were explored.Results:All patients underwent prophylactic central lymph node dissection.Lymph node metastasis occurred in 26 patients in the central region and in 13 patients in the lateral neck region.The rate of lymph node metastasis in the central region of men was 41.18%,and the rate of lymph node metastasis in the lateral neck region was 23.53%,which were significantly higher than that of women's 30.16%and 14.29%.The differences were statistically significant(P<0.05).The regional metastasis rate of the patients of≤45 years was 45.83%,and the lateral neck region metastasis rate was 20.83%,which were significantly higher than those of patients>45 years old(12.50%,9.38%)and the differences were statistically significant(P<0.05).The lymph node metastasis rate in the central region and in the lateral neck region of tumor diameter<0.5 cm were 27.27%and 9.09%respectively,which were significantly lower than those of the tumor diameter 0.5-1.0 cm(38.89%,25.00%)(P<0.05).The rate of lymph node metastasis in the central region of single focus was 20.37%,which was significantly lower than that of 57.69%in the multifocal lesions;the rate of lymph node metastasis in the cervical region of the single lesion was 11.11%,which was significantly lower than 26.92%in the multifocal area;the differences were statistically significant(P<0.05).The metastasis rate of the patients with extrathyroidal invasions in the central area was 60.00%,which is significantly higher than that without extrathyroidal invasions(30.67%).About the tumor neck invasion of the lateral neck region,the lymph node metastasis rate of the patients with extrathyroidal invasions was 40.00%,which was significantly higher than that without extrathyroidal invasions(14.67%).The differences were statistically significant(P<0.05).Logistic regression analysis showed that gender and tumor size were independent influencing factors of lymph node metastasis in the central and lateral neck regions(P<0.05).Conclusion:Young,male,multifocal,tumor diameter 0.5-1.0 cm and extrathyroidal invasions are risk factors for cervical lymph node metastasis in patients with PTMC.Gender and tumor size are independent factors affecting central/lateral cervical lymph node metastasis in PTMC patients.