Analysis Of Risk Factors For Predicting Central Lymph Node Metastasis In Papillary Thyroid Microcarcinoma

Objective: We aimed to determine the predictive factors for central compartment lymph node metastasis(CCLNM) in papillary thyroid microcarcinoma(PTMC). The outcome of the current study may guide the therapeutic strategy of PTMCs.Methods : We retrospected the papillary thyroid microcarcinoma cases who had undertook thyroidectomy plus central compartment lymph node dissection in general surgery of Tianjin medical university general hospital. The clinical and pathological findings of the PTMCs recently three years were collected and analyzed. We collected Preoperative fine-needle aspiration cytology washout liquid of the PTMCs recently one year and BRAFV600 E mutation analysis was performed using a direct sequencing method. The characteristics on conventional ultrasonography and elastography of the PTMCs recently one year were collected and analyzed. Predictive risk factors for central compartment lymph node metastases were quantified.Results:89(42.8%) of 208 PTMC patients who had undertook thyroidectomy plus central compartment lymph node dissection had CCLNM recently three years. 30(41.7%) of 72 PTMC cases had CCLNM recently one year. 34(47.2%) of those 72 cases had tumors that expressed BRAFV600 E mutation. Male gender(P<0.05), tumor size(>5mm; P<0.05), multifocality(P<0.05), capsule invasion(P<0.05) and lateral LNM(P<0.05) were significant variables predictive of CCLNM from PTMC in univariate analysis. BRAFV600 E mutation was associated significantly with CCLNM involvement(P<0.05). Univariate analysis indicated that PTMCs with CCLNM were more often nodule microcalcifications(P<0.05) and irregular(P<0.05) than those without CCLNM. Age, Bilateral, Nodule margin, Lymphocytic thyroiditis, Nodule echogenicity, Elastography US characteristics were not significantly related to the presence of CCLNM.Conclusions: BRAFV600 E gene mutations can be identified successfully on FNA washout liquid material. The risk factors such as male gender, tumor size > 5 mm, multifocality, capsule invasion and Lateral LNM that can be identified preoperatively or intraoperatively should be considered particularly for determination of prophylactic CCLND in patients with PTMC. The presence of a BRAFV600 E mutation maypreoperatively predict the CCLNM of PTMC, suggesting a more aggressive surgical approach. preoperative thyroid nodule characteristics on conventional US such as microcalcifications and nodule irregular may serve as a useful tool to predict central compartment lymph node metastases in PTMC.