The utility of sentinel Lymph node biopsy in the lateral neck in papillary thyroid carcinoma.

Background: Regional lymph node metastases (LNMs) are very common in papillary thyroid carcinoma (PTC) and associate with locoregional recurrence. The appropriate management of cervical lymph nodes is very important. Therefore, this study evaluated the application of sentinel lymph node biopsy (SLNB) in the lateral neck in PTC patients. Methods: This prospective study was conducted from 1 November 2015 to 31 December 2017 and recruited 78 PTC patients treated with SLNB in the lateral neck and prophylactic lateral neck dissection (compartments II-IV) followed by thyroidectomy or lobectomy and central neck dissection. Results: There were 78 PTC patients enrolled and sentinel lymph nodes (SLNs) were detected among 77 patients. A total of 30 patients were diagnosed with SLN metastases (SLNMs). The remaining 47 patients were pathologically negative of SLN, whereas 4 patients were found with metastases in the non-SLN samples. The detection rate, sensitivity, specificity, and accuracy rate of SLNB in the lateral neck were 98.7%, 87.1%, 98.7%, and 93.6%, respectively. However, the values varied greatly in each specific compartment of the lateral neck, and all of them were no more than 80%. These 34 PTC patients diagnosed with lateral compartment LNM (LLNM) were more likely to be younger (41.38 vs. 48.95 years old, p = 0.002) and exhibit extrathyroidal extension (56.8% vs. 31.7%, p = 0.026) and central compartment LNM (66.7% vs. 12.1%, p < 0.001). Tumors located in the upper third of the thyroid lobe also had a significantly higher probability of LLNM compared with those in middle or inferior location (66.7% vs. 35.3% vs. 34.8%, p = 0.044). At last, age (OR=0.912, p = 0.026), tumor location (upper vs inferior, OR=17.478, p = 0.011), and central compartment LNM (OR=25.364, p < 0.001) were independently predictive of LLNM. Conclusions: SLNB can help surgeons to identify some PTC patients who may benefit from therapeutic lateral neck dissection and protect some patients from prophylactic lateral neck dissection. However, it cannot accurately indicate specific lateral compartment-oriented neck dissection. Meanwhile, LLNM is more likely to occur in PTC patients with younger age or upper pole tumors or central compartment LNM.

How Many Contralateral Carcinomas in Patients with Unilateral Papillary Thyroid Microcarcinoma are Preoperatively Misdiagnosed as Benign?

BACKGROUND: The decision to perform a total thyroidectomy (TT) for unilateral papillary thyroid microcarcinoma (PTMC) with nodules in the contralateral lobe remains controversial. The aim of this study was to investigate the rate of contralateral carcinomas that are preoperatively misdiagnosed as benign. METHODS: From October 2011 to October 2015, a total of 347 patients with unilateral PTMC and contralateral benign nodules who were treated with a TT at a single institution were enrolled. All patients underwent preoperative fine needle aspiration and ultrasonography (US). Clinicopathological features such as age, sex, laterality, tumor size, central lymph node metastases, capsular invasion, TgAb and TPOAb levels, Hashimoto's thyroiditis, nodule number in both lobes according to preoperative US, and primary carcinoma number in the final postoperative pathology report were all analyzed to investigate the rate and predictive factors of contralateral carcinoma. RESULTS: A total of 100 patients (28.9 %) were diagnosed with papillary thyroid carcinoma in the contralateral lobe. A multivariate analysis showed that tumor size, nodule number in the contralateral lobe, and multifocality of the primary tumor were all independent predictive factors of contralateral carcinoma in patients with unilateral PTMC and contralateral benign nodules. CONCLUSIONS: According to our findings, the rate at which contralateral carcinomas are preoperatively misdiagnosed as benign is 28.9 %. A TT is essential for unilateral PTMC with a primary tumor size >5 mm, multifocal primary carcinomas or multifocal benign nodules in the contralateral lobe.