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Background/objective: Although papillary thyroid carcinoma (PTC) has an excellent prognosis, it can cause central lymph node metastasis (CLNM) which can increase local recurrence. Intraoperative pathologic evaluation (IOPE) can provide evidence regarding CLNM and help surgeons determine the appropriate surgical approach. The aim of this study was to evaluate the efficacy of IOPE and to determine risk factors associated with CLNM in unilateral PTC without preoperative clinical evidence of CLNM., Methods: Medical charts of 227 patients who had unilateral PTC without clinical lymph node metastasis preoperatively were reviewed retrospectively. They were scheduled for thyroid lobectomy and prophylactic central lymphadenectomy (CND) from January 1, 2017 to December 31, 2017., Results: Total follow-up period was 47.6 ± 10.6 months. CLNM was identified in 57 (25.1%) patients during IOPE and in 72 (31.7%) patients during final pathological analysis. The sensitivity and specificity of IOPE were 76.4% and 98.7%, respectively. IOPE through central lymph node dissection was safely performed with low complications (vocal cord palsy, 5.7%; hypoparathyroidism, 22.8%). Age < 55 years, echogenic foci on preoperative ultrasonography, and extrathyroidal extension at final pathological report were significantly associated with an increased risk of CLNM (p = 0.006, p < 0.001, and p < 0.001, respectively). In terms of oncological outcomes, there was no significant difference between the true negative and false negative results in IOPE., Conclusion: IOPE can safely provide accurate information for determining disease status and surgical extent. Further long-term studies are needed to evaluate clinical benefits of IOPE., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023 Asian Surgical Association and Taiwan Robotic Surgery Association. Published by Elsevier B.V. All rights reserved.)

Background: The efficacy of prophylactic central compartment lymph node dissection for papillary thyroid carcinoma remains controversial. We performed a randomized controlled trial to evaluate the efficacy and safety of prophylactic central compartment lymph node dissection in patients with papillary thyroid carcinoma., Methods: In this parallel-group randomized controlled trial, we assessed 101 patients aged 20 to 70 years with small/noninvasive papillary thyroid carcinoma and no clinical metastases or history of cervical surgery/radiation exposure. Randomization ran from April 2015 to November 2017. Data were collected between April 2015 and October 2020. Of the 101 enrolled patients, 50 underwent total thyroidectomy (TTx group) and 51 underwent total thyroidectomy as well as prophylactic central compartment lymph node dissection (TTx+pCND group). Surgical completeness, local recurrence, successful ablation, postoperative complication, and papillary thyroid carcinoma upstaging were compared between the 2 groups., Results: No patient showed structural recurrence after 46.6 ± 9.1 months of follow-up. Both groups had similar rates of surgical completeness and successful ablation. There was no difference in the incidence of complications. More patients were upstaged to pN1a in the TTx+pCND group compared to those in the TTx group (P < .05)., Conclusions: Prophylactic central compartment lymph node dissection detected more lymph node metastases but did not affect recurrence. The 2 groups showed similar outcomes with regard to surgical completeness, successful ablation, and complications. In conclusion, for small/noninvasive papillary thyroid carcinoma without clinical evidence of lymph node metastases, prophylactic central compartment lymph node dissection may not be required if total thyroidectomy is planned., (Copyright © 2021. Published by Elsevier Inc.)

Background: Despite active studies of the clinical importance of BRAF V600E , suitable research models to investigate the role of this mutation in the etiopathogenesis of human thyroid cancers are limited. Thus, we generated cell lines by transducing the simian virus (SV)-40 immortalized human thyroid cell line Nthy-ori 3-1 (Nthy) with lentiviral vectors expressing either BRAF WT (Nthy/WT) or BRAF V600E . Nthy/WT and Nthy/V600E cells were then xenografted into mice to evaluate the carcinogenic role of BRAF V600E . Methods: Each cell line was subcutaneously injected into NOD.Cg-Prkdc scid Il2rg tm1Wjl /SzJ mice, and a pathological analysis was performed. The effects of the mutation were further verified by using a BRAF V600E -selective inhibitor (PLX-4032, vemurafenib). The transcriptome was analyzed by RNA sequencing and compared with data from The Cancer Cell Line Encyclopedia and Gene Expression Omnibus. Results: While Nthy/WT was not tumorigenic in vivo , Nthy/V600E formed tumors reaching 2784.343 mm 3 in 4 weeks, on average. A pathological analysis indicated that Nthy/V600E tumors were dedifferentiated thyroid cancer. We found metastases in the lung, liver, and relevant lymph nodes. A transcriptomic analysis revealed 5512 differentially expressed genes (DEGs) between the mutant and wild-type cell lines, and more DEGs were shared with anaplastic thyroid cancer than with papillary thyroid cancer. BRAF V600E activated the cell cycle mainly by regulating G1/S phases. PLX-4032 treatment significantly inhibited tumor growth and metastasis. Conclusions: Our data show that BRAF V600E plays a pivotal role in the carcinogenic transformation of an SV40-transfected immortalized normal human thyroid cell line. This xenograft model is expected to contribute to studies of the etiopathogenesis and treatment of highly malignant thyroid cancers.