Intraoperative pathologic evaluation of central compartment lymph nodes in patients undergoing lobectomy for unilateral papillary thyroid carcinoma.

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.

Anti-adhesive effect and safety of a thermosensitive adhesion barrier (Mediclore) for thyroid surgery: a double-blinded randomized controlled trial.

Purpose: Postoperative adhesions after thyroidectomy adversely affect patients' quality of life. This study assessed the anti-adhesive effect and safety of thermosensitive sol-gel agents for patients undergoing thyroidectomy. Methods: A double-blind parallel-group randomized clinical trial involving patients aged 20-70 years undergoing thyroidectomy for thyroid nodules was conducted. From August 2017 to April 2020, 90 patients were randomly assigned to the experimental (n = 45, thermosensitive sol-gel agent applied to the surgical site) and control (n = 45, no treatment) groups in a 1:1 ratio. All patients were assessed using a questionnaire for swallowing difficulty, wrinkle problems, and inflammation at 2 weeks, 3 months, and 6 months after thyroid surgery. For reoperated patients, the degree of adhesion was evaluated according to the adhesion-evaluation score system (range, 0-4). Results: During the follow-up period of 6.50 ± 1.38 months, the swallowing difficulty, wrinkle problem, and inflammation were improved in both groups. However, there was no statistically significant difference between the control and experimental groups related to swallowing difficulty, wrinkle problems, and inflammation. Two patients in the control group and 1 in the experimental group who underwent reoperation had an adhesion-evaluation score of 3 points. There were no adverse effects or allergic reactions. Conclusion: A thermosensitive sol-gel agent can be safely used as an anti-adhesive barrier. However, this study did not reveal its efficacy for postoperative adhesions. A more objective and systematic study is required in the future.

A prospective randomized controlled trial to assess the efficacy and safety of prophylactic central compartment lymph node dissection in papillary thyroid carcinoma.

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.

Comparative study of bilateral axillo-breast approach endoscopic and robotic thyroidectomy: propensity score matching analysis of large multi-institutional data.

PURPOSE: The aim of this study was to compare the large multi-institutional data of surgical outcomes of bilateral axillo-breast approach (BABA) robotic (RT) and endoscopic thyroidectomy (ET) and to evaluate the merits of robotic thyroidectomy. METHODS: From 2004 to 2015, 1,029 patients underwent BABA ET, and from 2008 to 2015, 2003 patients underwent BABA RT in 3 large volume centers in Korea. Two groups were retrospectively compared in terms of clinicopathologic characteristics, complications, surgical completeness, and long-term outcomes using propensity score matching analysis. RESULTS: Both groups had similar demographic characteristics including age, sex, tumor size, pathologic stage, and hospital stay after matching. Each group had similar rate of transient hypoparathyroidism, however, ET showed significantly higher rate of permanent hypoparathyroidism (ET 5.2% vs. RT 2.3%, P = 0.05), and transient vocal cord palsy (ET 14.4% vs. RT 9.1%, P = 0.006). Total operation time was longer in the ET group irrespective of surgical extents, including lobectomy (P = 0.016), total thyroidectomy (P = 0.031), and total thyroidectomy with central lymph node dissection (P = 0.019). The rate of patients with off-Tg under 1.0 ng/mL after 1st ablation was significantly higher in RT than ET group (ET 64.6% vs. RT 92.7%, P < 0.001). In long-term follow-up of cancer patients, 1.4% experienced recurrence after ET (10 cases), while 0.3% cases experienced recurrence after RT (5 cases) (P < 0.001). CONCLUSION: Both ET and RT can be safe and effective methods to treat thyroid diseases. However, the application of robotic system may help to overcome the limitations of the instruments and surgeon's skills.

BRAFV600E Transduction of an SV40-Immortalized Normal Human Thyroid Cell Line Induces Dedifferentiated Thyroid Carcinogenesis in a Mouse Xenograft Model.

Background: Despite active studies of the clinical importance of BRAFV600E, 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 BRAFWT (Nthy/WT) or BRAFV600E. Nthy/WT and Nthy/V600E cells were then xenografted into mice to evaluate the carcinogenic role of BRAFV600E. Methods: Each cell line was subcutaneously injected into NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ mice, and a pathological analysis was performed. The effects of the mutation were further verified by using a BRAFV600E-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 mm3 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. BRAFV600E activated the cell cycle mainly by regulating G1/S phases. PLX-4032 treatment significantly inhibited tumor growth and metastasis. Conclusions: Our data show that BRAFV600E 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.

Impact of smoking on thyroid gland: dose-related effect of urinary cotinine levels on thyroid function and thyroid autoimmunity.

Cigarette smoking is believed to affect thyroid function and autoimmune thyroid disease. However, there is little information to analyze their association using objective biomarkers. The aim of this study was to investigate the dose-related effect of smoking on thyroid hormones and thyroid peroxidase antibody (TPO Ab) using urinary cotinine levels and a population-based cohort. The present study used the thyroid hormone and urinary cotinine dataset from sixth Korean National Health and Nutrition Examination Survey in 2014 and 2015, and a total of 4249 participants were included. Dose-response relationships between thyroid hormone (free T4, TSH, and TPO Ab) and urinary cotinine levels were estimated using ANCOVA after adjustment for all variables (age, height, weight, alcohol, exercise, and log- transformed iodine in urine). Urinary cotinine level was negatively correlated with TSH. The estimated coefficients were -0.0711 in males and -0.0941 in females (p < 0.0001). TPO Ab titer was positively correlated with cotinine levels in males (p < 0.0001). Our findings indicated a significant dose-related effect of urinary cotinine level on thyroid function, and thyroid autoimmunity.

Application of a Perception Neuron® System in Simulation-Based Surgical Training.

While multiple studies show that simulation methods help in educating surgical trainees, few studies have focused on developing systems that help trainees to adopt the most effective body motions. This is the first study to use a Perception Neuron® system to evaluate the relationship between body motions and simulation scores. Ten medical students participated in this study. All completed two standard tasks with da Vinci Skills Simulator (dVSS) and five standard tasks with thyroidectomy training model. This was repeated. Thyroidectomy training was conducted while participants wore a perception neuron. Motion capture (MC) score that indicated how long the tasks took to complete and each participant's economy-of-motion that was used was calculated. Correlations between the three scores were assessed by Pearson's correlation analyses. The 20 trials were categorized as low, moderate, and high overall-proficiency by summing the training model, dVSS, and MC scores. The difference between the low and high overall-proficiency trials in terms of economy-of-motion of the left or right hand was assessed by two-tailed t-test. Relative to cycle 1, the training model, dVSS, and MC scores all increased significantly in cycle 2. Three scores correlated significantly with each other. Six, eight, and six trials were classified as low, moderate, and high overall-proficiency, respectively. Low- and high-scoring trials differed significantly in terms of right (dominant) hand economy-of-motion (675.2 mm and 369.4 mm, respectively) (p = 0.043). Perception Neuron® system can be applied to simulation-based training of surgical trainees. The motion analysis score is related to the traditional scoring system.

Transoral endoscopic surgery for papillary thyroid carcinoma: initial experiences of a single surgeon in South Korea.

PURPOSE: The transoral endoscopic thyroid surgery vestibular approach (TOETVA) is one of the newest techniques which do not result in an anterior neck scar. We report herein our initial experience with TOETVA and its short-term outcomes in patients with papillary thyroid carcinoma (PTC). METHODS: This case series consisted of all consecutive patients who underwent TOETVA in our institution between August 2016 and June 2017. Indications for TOETVA were an fine needle aspiration-confirmed PTC or follicular neoplasm, an intrathyroidal tumor with a diameter of less than 2 cm, and no clinical evidence of central or lateral lymph node metastasis. A total of 20 patients underwent TOETVA and we retrospectively reviewed clinicopathologic data and short-term postoperative outcomes. RESULTS: Among the 20 TOETVA cases, 7 were total thyroidectomy, 12 were lobectomy and 1 was wide isthmusectomy. Mean age was 50.8 years and mean operation time was 152 ± 51.4 minutes. Tumor size ranged from 0.2-1.4 cm and the mean size of harvested central lymph nodes was 2.8 (range, 0-10). Neither mental nerve injury nor surgical site infection occurred. One patient had transient vocal cord palsy and 1 patient developed a neck seroma. Among 7 total thyroidectomy patients, 3 patients developed transient hypocalcemia. CONCLUSION: Transoral thyroid surgery could be an alternative surgical option for some PTC patients.

Erratum: Addition of funding statement: Clinical characteristics of papillary thyroid carcinoma arising from the pyramidal lobe.

[This corrects the article on p. 123 in vol. 92, PMID: 28289665.].

Clinical characteristics of papillary thyroid carcinoma arising from the pyramidal lobe.

PURPOSE: Papillary thyroid carcinoma (PTC) arising from the pyramidal lobe is rare; therefore, clinicopathologic evaluation is lacking. In addition, the rate of occult malignancy in the pyramidal lobe after thyroid surgery is unclear. This study is to evaluate the clinical characteristics of PTCs that involve the pyramidal lobe. METHODS: The study enrolled 1,107 patients who underwent thyroid surgery for PTC at Seoul National University Hospital from 2006 to 2015. Pyramidal lobe status in pathologic reports was clear in all cases. "Pyramidal lobe-dominant PTC" was defined as single pyramidal lobe cancer or multifocal cancer with larger pyramidal lobe tumor. "Incidental pyramidal lobe PTC" was defined as occult cancer identified after thyroidectomy or as multifocal cancer with smaller pyramidal lobe tumor. RESULTS: Ten patients were included in the pyramidal lobe-dominant PTC group. The mean age was 58 ± 12.5 years, and the mean tumor size was 0.7 ± 0.7 cm. Cervical lymph node metastasis was found in 5 patients (50%). Three patients had microscopic lymphatic invasion, and 7 had advanced American Joint Comitee on Cancer (AJCC) stage disease (5 with stage III and 2 with stage IV). Compared with conventional PTC (n = 1,058), pyramidal lobe-dominant PTC was significantly associated with lymphatic invasion (P = 0.031) and advanced AJCC stage (P = 0.022). The prevalence of incidental pyramidal lobe PTC was 3.56%. CONCLUSION: Pyramidal lobe PTC is relatively small in size; however, the rate of extrathyroidal extension and lymph node metastasis is high. Preoperative evaluation of nodal status is important, and the extent of surgery should be determined in accordance with the preoperative diagnosis.