High Risk Factors For Lymph Node Metastasis Of Papillary Thyroid Microcarcinoma(PTMC) And Correlation Of BRAF Gene Mutation

Objective: Papillary thyroid carcinoma becomes more and more common in today's daily clinical work,which is an endocrine system malignant tumor with a rapid rise in incidence in recent years.It has a tendency to clear lymph node metastasis.However,there is still controversy over the high risk factors of PTMC lymph node metastases and surgical scope of PTMC at home and abroad.Therefore,to explore the influence factors of the transfer of PTMC are the problems needed to be solved.In this study,we investigated high-risk factors for lymph node metastasis(LNM)of papillary thyroid microcarcinoma(PTMC)and calculated 10-year-survival rate of the patients and the BRAF gene V600 E mutation site was sequenced in the pathological specimens of PTMC patients,the puncture lavage fluid and the peripheral serum in order to find personalized therapy for PTMC.Methods: 1.We retrospectively analyzed the clinical data of 3607 PTMC patients accepted surgery in our hospital from 2005 to 2015.Statistics of central neck and lateral neck lymph node metastasis rate were collected to figure out the relationship between gender,age,tumor size,multifocal and cervical lymph node metastasis.Univariate and multivariate analyses were performed to identify the factors associated with metastasis.The survival rate of patients was analyzed by Kaplan-Meier,and the influencing factors were investigated.2.80 paraffin specimens from patients with PTMC were collected,and the BRAF gene mutations were detected by fluorescence PCR method.The correlation and sensitivity and specificity between BRAF gene mutation and PTMC lymph node metastasis were detected.At the same time,it is necessary to explore whether the BRAF gene can be used as a reliable gene target to determine the scope of surgery for thyroid cancer before operation.Results: 1.The LNM rate of all 3607 PTMC patients is 17.13%.Central lymph node metastasis rate is 16.86%,which is related to gender(male vs female,P<0.01),age(<45 vs ?45,P<0.01),tumor diameter(P<0.01)and multifocality(P<0.01).Lateral lymph node metastasis rate is 1.05%,which is related to age(<45 vs ?45,P<0.01)and tumor diameter(P<0.01).The 10-year-survival rate is 93.0% and 10-year recurrence-free survival rate is 87.5%.The 10-year-tumor-free survival rate of the patients with lymph node metastasis was 75.4%,and the 10-year-tumor-free survival rate of the patients without lymph node metastasis was 89.5%(P > 0.05).2.Among 80 patients,59 patients were diagnosed with papillary carcinoma by preoperative FNAC,accounting for 73.75%.FNAC diagnosis 16 cases of suspected papillary carcinoma with features of puncture cells,nuclear crowding,nuclear heteromorphism,accounting for 20%,and FNAC diagnosed 5 cases of heterosexual cells,accounting for 6.25%.61 people were BRAF(+)in FNAC puncture syringe and 19 people BRAF(-).75 patients were diagnosed with thyroid papillary micro carcinoma by paraffin pathology after operation,and the accuracy of preoperative diagnosis was 93.75%(75/80).The mutation rate of BRAF gene in paraffin wax specimens was 88.75%(71/80),and the BRAF mutation rate in puncture cell lavage fluid was 76.25%(61/80).The mutation rate of BRAF gene in peripheral blood was 21.25%(17/80).Paraffin pathology confirmed that the lymph node metastases were 17,and the coincidence rate with the BRAF gene mutation was 32.5%(26/80).Conclusion: 1.PTMC trends to metastasize to cervical lymph node,especially in male gender,age younger than 45,multifocal tumors and maximal tumor diameter larger than 0.7 cm.Patients younger than 45 years old and with longer tumor diameter(>0.7cm)are more likely to have lateral cervical lymph node metastases.There is no significant correlation between these clinical features and the 10-year survival rate.2.PTMC has high mutation rate in BRAF V600 E gene.Detection of puncture lavage fluid BRAF gene can better response in patients with actual BRAF mutation,which has certain significance to the diagnosis of thyroid carcinoma.Serum BRAF gene mutation detection positive rate is low,which is not mature as a preoperative diagnosis basis.There was no significant correlation between the mutation of BRAF gene transfer and PTMC lymph node metastases.