Role of BRAF V600E mutation as an indicator of the extent of thyroidectomy and lymph node dissection in conventional papillary thyroid carcinoma

An Online Model for Central Lymph Node Metastases in Papillary Thyroid Carcinoma With BRAF V600E Mutation

OBJECTIVE

To construct a predictive model to direct the dissection of the central lymph nodes in papillary thyroid cancer (PTC) with BRAF V600E mutation by identifying the risk variables for central lymph node metastases (CLNM).

METHODS

Data from 466 PTC patients with BRAF V600E mutations underwent thyroid surgery was collected and analyzed retrospectively. For these patients, we conducted univariate and multivariate logistic regression analysis to find risk variables for CLNM. To construct a nomogram, the independent predictors were chosen. The calibration, discrimination, and clinical utility of the predictive model were assessed by training and validation data.

RESULTS

CLNM was present in 323/466 PTC patients with BRAF V600E mutations. By using univariate and multivariate logistic regression, we discovered that gender, age, tumor size, multifocality, and pathological subtype were all independent predictors of CLNM in PTC patients with BRAF V600E mutations. A predictive nomogram was created by combining these variables. In both training and validation groups, the nomogram demonstrated great calibration capacities. The training and validation groups' areas under the curve (AUC) were 0.772 (specificity 0.694, sensitivity 0.728, 95% CI: 0.7195-0.8247) and 0.731 (specificity 0.778, sensitivity 0.653, 95% CI: 0.6386-0.8232) respectively. According to the nomogram's decision curve analysis (DCA), the nomogram might be beneficial. As well, an online dynamic calculator was developed to make the application of this nomogram easier in the clinic.

CONCLUSION

An online nomogram model based on the 5 predictors included gender, age, pathological subtype, multifocality, and tumor size was confirmed to predict CLNM and guide the central lymph nodes dissection in PTC patients with BRAF V600E mutations.

BRAFV600E genetic testing should be recommended for Bethesda III or V thyroid nodules based on fine-needle aspiration

The preoperative diagnosis of thyroid nodules now routinely includes BRAFV600E genetic testing in most provincial and municipal hospitals in China. This study identified the most suitable patients of thyroid nodule for BRAFV600E genetic testing. We retrospectively collected data of patients from the Hospital Information System that had undergone fine needle aspiration biopsy (FNAB) from May 2019 to December 2021. Data of FNAB, BRAFV600E genetic testing, and post-surgical pathological diagnosis were collected. A total of 12,392 patients were included in this study. Among them, 7,010 patients underwent solely FNAB, while 5,382 patients had both FNAB and BRAFV600E genetic testing. In the FNAB group, 2,065 thyroid nodules were surgically removed, with a 93.12% malignancy rate. In the FNAB + BRAF group, 2,005 nodules were dissected, and the malignancy rate was 98.20%. However, it was evident that in the subgroups, the combination of FNAB and BRAFV600E genetic testing only benefited Bethesda III (p < 0.001) and V (p = 0.001) nodules. Overall, the combination of FNAB with BRAFV600E genetic testing significantly improved the malignancy rate of surgical thyroid nodes at our hospital when compared to FNAB alone. The subgroup analysis showed that BRAFV600E genetic testing only benefited Bethesda III and V nodules. These findings provide a clinical reference for rationally selecting the most suitable population for BRAFV600E genetic testing.

Guideline for the Surgical Management of Locally Invasive Differentiated Thyroid Cancer From the Korean Society of Head and Neck Surgery

The aim of this study was to develop evidence-based recommendations for determining the surgical extent in patients with locally invasive differentiated thyroid cancer (DTC). Locally invasive DTC with gross extrathyroidal extension invading surrounding anatomical structures may lead to several functional deficits and poor oncological outcomes. At present, the optimal extent of surgery in locally invasive DTC remains a matter of debate, and there are no adequate guidelines. On October 8, 2021, four experts searched the PubMed, Embase, and Cochrane Library databases; the identified papers were reviewed by 39 experts in thyroid and head and neck surgery. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence, and to develop and report recommendations. The strength of a recommendation reflects the confidence of a guideline panel that the desirable effects of an intervention outweigh any undesirable effects, across all patients for whom the recommendation is applicable. After completing the draft guidelines, Delphi questionnaires were completed by members of the Korean Society of Head and Neck Surgery. Twenty-seven evidence-based recommendations were made for several factors, including the preoperative workup; surgical extent of thyroidectomy; surgery for cancer invading the strap muscles, recurrent laryngeal nerve, laryngeal framework, trachea, or esophagus; and surgery for patients with central and lateral cervical lymph node involvement. Evidence-based guidelines were devised to help clinicians make safer and more efficient clinical decisions for the optimal surgical treatment of patients with locally invasive DTC.

[Modern aspects influencing the management of patients with papillary thyroid cancer]

Thyroid cancer (TC) is the most common malignant tumor of the endocrine glands and accounts to 3% of the total structure of oncological morbidity. Papillary thyroid cancer (PTC) is the most common histological variant of thyroid malignancies. It accounts for about 85% of all cases of thyroid cancer. Despite good postoperative results and excellent survival compared to many other malignancies, tumor metastases to the paratracheal lymph nodes are quite common. This review of the literature considers the current personalized approach to patients with papillary thyroid cancer and current aspects influencing the management of patients with PTC.

Prognostic Significance of BRAF V600E Mutation and CPSF2 Protein Expression in Papillary Thyroid Cancer

The early-stage diagnosis of papillary thyroid cancer (PTC) has significantly increased in incidence worldwide without any beneficial impact on survival. In order to improve the risk assessment in PTC, we have conducted a retrospective study in which we analyzed the BRAF V600E mutation and CPSF2 protein expression as prognostic markers on archival tissue samples of 49 patients without (control group) and 97 patients with (study group) PTC metastases in the cervical lymph nodes at the time of initial diagnosis. Our aim was to correlate the BRAF V600E mutation and the expression of CPSF2 protein with the clinical and pathological features of PTC. The expression of CPSF2 protein was evaluated via immunohistochemistry and graded semi-quantitatively. The presence of the BRAF V600E mutation was determined via real-time polymerase chain reac-tion (PCR). CPSF2 protein < 3+ intensity expression was correlated with more frequent recurrences (Fisher-Freeman-Halton exact test; p = 0.010; 95% CI: 1.26−22.03), and patients who presented with the BRAF V600E mutation and CPSF2 protein expression < 3+ intensity had shorter disease-free survival (log-rank test; 105.0 months vs. 146.6 months; p < 0.001; HR 8.32, 95% CI: 2.91−23.83), whereas patients with PTC who had CPSF2 expression 3+ had longer disease-free survival in correlation with other lower intensity expressions of CPSF2 protein (log-rank test; 139.7 months vs. 129.6 months; p = 0.008). The multivariate analysis showed that younger patients with CPSF2 protein expression <3+ and the BRAF V600E mutation are at an increased risk for recurrence and require more intensive monitoring (Cox proportional hazards regression model; X2 = 17.5, df = 10, p = 0.025). Our results correlate the BRAF V600E mutation and CPSF2 protein expression with recurrence and disease-free survival as relevant prognostic factors for PTC.

Genotypes of Papillary Thyroid Carcinoma With High Lateral Neck Metastasis in Chinese Population

Papillary Thyroid Carcinoma (PTC) is one of the most commonly diagnosed cancer types in China, characterized by its early age at diagnosis and high 25-year survival rate. Distinct mutational patterns in PTC have been linked to activation of the mitogen-activated protein kinase (MAPK) signaling pathway. To explore the clinical significance of genomic variation patterns in Chinese patients with thyroid carcinoma, we investigated the genomic variants in 83 PTC cases with complete clinical records. The mutational patterns were evaluated using a 688-gene panel which covered known driver genes in PTC tumorigenesis, and featured genetic markers in various PTC-related pathways. We evaluated the relationship between mutational landscape and various clinical information in PTC patients with lateral lymph node metastasis. BRAF V600E was the most common mutation. Mutations in NF1, CDC27, PMS2 and PPP4R2 were more common in men, and mutations in NF1, PMS2 and TERT were related to lateral lymph node metastasis. According to the clustering of mutational patterns, we show that the underline driving mechanisms in lateral lymph node metastasis can be divided into two major groups (BRAF-TERT pathway, and NF1-PMS2 pathway). When combined with the TERT mutations, the BRAF mutation group was prone to lateral lymph node metastasis, particularly in elderly women. The NF1 mutations usually co-existed with PMS2 mutations, and this group included more men and young patients who had a high tumor mutational burden and lateral lymph node metastasis rate.

Risk and Prognostic Factors for BRAFV600E Mutations in Papillary Thyroid Carcinoma

Background

Over the past ten years, the incidence rate of papillary thyroid carcinoma (PTC) worldwide has been increasing rapidly year by year, with the incidence rate increasing 6% annually. PTC has become the malignant tumor with the highest growth rate in the world that fourteen PTC-related mutant genes have been identified. Whether the BRAF^V600E mutation related to more aggressive clinicopathologic features and worse outcome in PTC remains variable and controversial. We aim to investigate the risk factors that may predict the BRAF^V600E mutation potential of these lesions and new prevention strategies in PTC patients.

Methods

A total of 9,908 papillary thyroid carcinoma patients with average 74.6% BRAF^V600E mutations were analyzed (RevMan 5.3 software) in this study. The PubMed, Embase, and ISI Web of Science databases were systematically searched for works published through December 15, 2021.

Results

The following variables were associated with an increased risk of BRAF^V600E mutation in PTC patients: age ≥ 45 years (OR = 1.39, 95%CI = 1.21–1.60, p < 0.00001), male gender (OR = 1.13, 95%CI = 0.99–1.28, p = 0.06), multifocality (OR = 1.22, 95%CI = 1.07–1.40, p = 0.004), lymph node metastasis (OR = 1.33, 95%CI = 0.79–2.23, p = 0.28), extrathyroidal extension + (OR = 1.61, 95%CI = 1.06–2.44, p = 0.03), vascular invasion + (OR = 2.04, 95%CI = 1.32–3.15, p = 0.001), and tumor node metastasis stage (OR = 1.61, 95%CI = 1.38–1.88, p < 0.00001). In addition, tumor size (>1 cm) (OR = 0.51, 95%CI = 0.32–0.81, p = 0.005) and distant metastasis (OR = 0.69, 95%CI = 0.22–2.21, p = 0.54) had no association or risk with BRAF^V600E mutation in PTC patients.

Conclusion

Our systematic review identified the following significant risk factors of BRAF^V600E mutation in PTC patients: age (≥45 years), gender (male), multifocality, lymph node metastasis, vascular invasion, extrathyroidal extension, and advanced tumor node metastasis stage (stages III and IV). Tumor size (>1 cm) and distant metastasis do not appear to be correlated with BRAF^V600E mutation in PTC patients.

Risk Factors for Contralateral Occult Papillary Thyroid Carcinoma in Patients with Clinical Unilateral Papillary Thyroid Carcinoma: A Case-Control Study

INTRODUCTION

Papillary thyroid cancer (PTC) is one of the most prevalent endocrine malignancies that has increased in recent decades around the world. Although the indicator for navigating the surgical extent in PTC patients is still in debate, a key issue is how to predict that there are undetected preoperative tumors in the contralateral thyroid lobe. This study aims to find risk factors for contralateral occult papillary thyroid cancer (COPTC) to facilitate more accurate surgical decisions made for patients with PTC.

MATERIALS AND METHODS

In our study, we included 229 patients who underwent total thyroidectomy plus central and ipsilateral lateral lymph nodes dissection from January 1, 2019, to September 1, 2021. Univariate and multivariate logistic regression analyses were conducted to assess the association between COPTC and clinical-pathological characteristics, as well as the relation between the diameter of the occult lesions and predictors. The forest plot was plotted to visualize the prediction factors from the output of the multivariate regression analysis. A ROC curve was used to evaluate the combining potency of all the risk factors.

RESULTS

Of the 229 patients included in our study, 46 with COPTC were assigned to the case group, representing 20.1% in this study. Multifocality in one lobe (OR = 2.21, P=0.03), intact capsule (OR = 2.54, P=0.01), central lymph node metastasis (OR = 3.00, P=0.02), and Hashimoto's thyroiditis (OR = 2.08, P = 0.04) are more prone to present contralateral occult papillary thyroid carcinoma. The ROC curve of the aggregate potency of the risk factors presents AUC = 0.701 (P < 0.001), and the best cutoff value was 2.02, with a sensitivity of 78.3% and specificity of 55.2%. Furthermore, there was no statistical correlation between the diameter of the occult tumor and the four obtained variables.

CONCLUSION

Patients with multifocality in one lobe, intact capsule, central lymph node metastasis, and HT may harbor contralateral papillary thyroid carcinoma. It is essential to be prudent to make a surgical or follow-up decision on these patients. In addition, more clinical rather than postoperative pathological indicators need to be revealed in the future.

Analysis of factors influencing the clinical outcome after surgery and 131I therapy in patients with moderate-risk thyroid papillary carcinoma

PURPOSE

Generally, the prognosis for papillary thyroid cancer (PTC) is favorable. However, the moderate risk involved warrants further evaluation. Hence, we investigated the clinical outcomes in patients with moderate-risk PTC following surgery and the first ¹³¹I therapy, as well as the relevant factors that influence the therapeutic efficacy.

METHODS

Retrospective analyses of 175 patients with medium-risk PTC who visited the Second Affiliated Hospital of Chongqing Medical University from September 2017 to April 2019 were conducted. In according with the 2015 American Thyroid Association (ATA) guideline treatment response evaluation system, the patients were categorized into the following groups: excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), and structurally incomplete response (SIR), of which IDR, BIR, and SIR were collectively referred to as the NER group. To compare the general clinical features between the 2 groups of patients, 2 independent samples t-tests, χ² test, and Mann-Whitney U-test were performed, followed by multivariate logistic regression analyses. With reference to the receiver operating characteristic (ROC) curve, the predicted value of ps-Tg to ER was evaluated, and the best cut-off value was determined. The subgroups with BRAF^V600E test results were analyzed by χ2 test only.

RESULTS

The treatment responses of 123 patients were ER, while those of 52 patients were NER. The differences in the maximum tumor diameter (U = 2495.50), the amount of metastatic lymph nodes (U = 2313.50), the size of metastatic lymph node (U = 2113.50), the metastatic lymph node ratio (U = 2111.50), metastatic lymph node location (χ² = 9.20), and ps-Tg level (U = 1011.00) were statistically significant. Multivariate regression analysis revealed that ps-Tg (OR = 1.209, 95% CI: 1.120-1.305) was an independent variable affecting ER. The cut-off value of ps-Tg for predicting ER was 6.915 ug/L, while its sensitivity and specificity were 69.2% and 89.4%, respectively.

CONCLUSIONS

Patients with smaller tumor size, fewer lymph nodes, lower metastatic lymph node ratio, metastatic lymph nodes in the central region, smaller lymph node size, and ps-Tg <6.915 ug/L demonstrated better therapeutic effects after the initial treatment.

BRAFV600E mutation test on fine-needle aspiration specimens of thyroid nodules: Clinical correlations for 4600 patients

Background

The BRAF^V600E mutation is valuable for the diagnosis, prognosis, and therapy of papillary thyroid cancer (PTC). However, studies related to this mutation have involved only a small number of patients. Therefore, we performed a large‐scale analysis from a single institute to evaluate the accuracy of combined fine‐needle aspiration (FNA) and BRAF^V600E mutation tests for PTC diagnosis.

Methods

A total of 4600 patients with thyroid nodules who underwent both FNA cytology and BRAF^V600E mutation analysis on FNA specimens were enrolled. The association between the BRAF^V600E mutation and clinicopathological features was analyzed. A separate analysis was performed for the 311 patients who underwent repeated FNA for comparison of cytological evaluation and BRAF^V600E mutation results. The diagnostic efficacy of the BRAF^V600E mutation test and cytologic diagnoses was evaluated for 516 patients who underwent preoperative FNA tests in comparison with conclusive postoperative histopathologic results.

Results

The cytology results of all 4600 FNA samples were categorized according to The Bethesda System for Reporting Thyroid Cytology (TBSRTC) stages I–VI, which accounted for 11.76%, 60.02%, 6.46%, 3.61%, 6.71%, and 11.43% of the samples, respectively. The BRAF^V600E mutation was detected in 762 (16.57%) FNA samples, with rates of 1.48%, 0.87%, 20.20%, 3.01%, 66.02%, and 87.81% for TBSRTC I–VI lesions, respectively. Among the 311 repeat FNA cases, 81.0% of the BRAF^V600E‐positive and 4.3% of the BRAF^V600E‐negative specimens with an initial indication of cytological non‐malignancy were ultimately diagnosed as malignant by repeat FNA (p < 0.001). Among the 516 patients who underwent thyroidectomy, the sensitivity and specificity of the BRAF^V600E mutation test alone for PTC diagnosis were 76.71% and 100.0%, respectively, which increased to 96.62% and 88.03%, respectively, when combining the BRAF^V600E mutation test with cytology. BRAF^V600E mutation was significantly associated with lymph node metastasis (p < 0.001), but not with age, gender, or tumor size.

Conclusions

The BRAF^V600E mutation test in FNA samples has potential to reduce false negatives in PTC diagnosis, and therefore plays an important role in the diagnosis of thyroid nodules, especially those with an indeterminate or nondiagnostic cytology, which should be considered for repeat FNA.

Nomograms to predict ipsilateral and contralateral central lymph node metastasis in clinically lymph node-negative patients with solitary isthmic classic papillary thyroid carcinoma

BACKGROUND

Isthmus-originating papillary thyroid carcinoma has unique clinicopathological characteristics. There are no specific guidelines regarding the extent of surgery for isthmic papillary thyroid carcinoma. We aimed to evaluate the characteristics of clinically lymph node-negative patients with solitary isthmic papillary thyroid carcinoma and to determine the best surgical protocol for these patients.

METHODS

A total of 904 patients diagnosed with solitary papillary thyroid carcinoma who underwent surgery were retrospectively reviewed. These patients were divided into the isthmic group (246 patients) or lobar group (658 patients). We compared the 2 groups and conducted a multivariate analysis to assess risk factors for ipsilateral and contralateral central lymph node metastasis in isthmic papillary thyroid carcinoma patients. Nomograms for predicting central lymph node metastasis in isthmic papillary thyroid carcinoma patients were developed and internal calibration was performed for these models.

RESULTS

Isthmic papillary thyroid carcinoma patients have a significantly higher incidence of extrathyroidal extension and central lymph node metastasis than do lobar papillary thyroid carcinoma patients. For isthmic papillary thyroid carcinoma patients, sex, BRAF V600E mutation, chronic lymphocytic thyroiditis, tumor size, margin, and extrathyroidal extension were independent risk factors of ipsilateral central lymph node metastasis. Body mass index, BRAF V600E mutation, tumor size, location, and extrathyroidal extension were independent risk factors of contralateral central lymph node metastasis. All the above factors were incorporated into nomograms, which showed the perfect discriminative ability.

CONCLUSION

Based on the predictive nomograms, we proposed a risk stratification scheme and corresponding individualized surgical treatment based on different nomogram scores. In the debate about prophylactic central neck dissection among clinically lymph node-negative patients with solitary isthmic papillary thyroid carcinoma, our nomograms provide the balance to avoid overtreatment and undertreatment through personal risk assessment.

Prospective Analysis of TERT Promoter Mutations in Papillary Thyroid Carcinoma at a Single Institution

Background: Papillary thyroid cancer (PTC) has the highest cancer incidence in Korea. It is known that some thyroid cancers have aggressive clinical behavior and a poor prognosis. Genomic studies have described some somatic mutations that are related to the aggressive features of thyroid cancer, such as the BRAF^V600E mutation. Recently, TERT promoter mutations were identified and reported as poor prognostic factors in PTC. Our aim was to identify the frequency and clinical impact of TERT promoter mutation in PTC. Methods: Analysis of both BRAF^V600E and TERT promoter mutations in thyroidectomy specimens began in February 2019. As of December 2020, 622 patients had been tested. Data were prospectively collected and retrospectively reviewed to ascertain clinical and pathologic variables. Results: TERT promoter mutations were identified in 13 patients (2.09%); 12 had the C228T mutation, and one had the C216T mutation. In total, ten patients had the BRAF^V600E mutation. TERT promoter mutation was significantly associated with advanced age (46.795 ± 12.616 versus 65.692 ± 13.628 years, p < 0.001), large tumor size (1.006 ± 0.829 versus 2.285 ± 1.938 cm, p = 0.035), extrathyroidal extension, surgical margin involvement, angioinvasion, BRAF^V600E mutation and advanced TNM stage, a higher MACIS score and a high proportion of radioactive iodine therapy application. Logistic regression showed that lymphatic and angioinvasion and BRAF^V600E mutation were predictive of TERT promoter mutation. Conclusions: Our study is the first to report the prospective results of TERT promoter mutations at a single tertiary hospital in Incheon, Korea. PTC with TERT promoter mutation was associated with more aggressive behavior than PTC with wild-type TERT gene status.

Predictive Factors for Occult Bilateral Papillary Thyroid Carcinoma

BACKGROUND

Bilateral papillary thyroid carcinoma (PTC) requires aggressive treatment, such as total thyroidectomy (TT). If there is only an isolated PTC focus in one lobe that can be diagnosed preoperatively, and it is unknown whether there are foci in the contralateral lobe that are too small to be detected, it is difficult to know whether to perform TT or to remove only the lobe with the isolated PTC focus. Here, we investigated the prevalence of and predictive factors for occult bilateral PTC that was only diagnosed unilaterally before surgery.

METHODS

This retrospective study involved 586 patients with unilateral PTC who were diagnosed preoperatively by ultrasound. They underwent TT and cervical lymph node dissection. According to the pathology, they were divided into unilateral PTC and bilateral (Bil)-PTC groups. Student's t test, chi-squared test, and multivariate analysis were performed to identify features of the malignant tumor that increased the likelihood of malignancy in the contralateral lobe. The prevalence of occult Bil-PTC was calculated.

RESULTS

Bil-PTC was found in 70 of 586 (11.95%) PTC patients. Multivariate analysis showed that vascularity (odds ratio[OR]: 2.180, 95% confidence interval [CI]: 1.142-4.162, p = 0.018) and ultrasound diagnosis of lymph node metastasis (USLNM) (OR: 2.056, 95% CI: 1.056-4.004, p = 0.034) were independent predictors of occult Bil-PTC.

CONCLUSION

The prevalence of occult PTC in the contralateral lobe was only 11.95%. Vascularity and USLNM were risk factors for Bil-PTC. In terms of these preoperative risk factors for PTC, TT should be cautiously performed in patients with preoperative diagnosis of PTC with isolated focus.

A Nomogram Based on Clinical and Ultrasound Characteristics to Predict Central Lymph Node Metastasis of Papillary Thyroid Carcinoma

BACKGROUND

The status of lymph nodes in the central compartment is crucial to determining the surgical strategies for papillary thyroid carcinoma (PTC). We aimed to develop a nomogram for predicting central lymph node metastasis (CLNM).

METHODS

A total of 886 PTC patients who underwent total thyroidectomy or lobectomy with central neck dissection (CND) from July 2019 to June 2020 were retrospectively retrieved. Clinical and ultrasound features were collected. Univariate and multivariate analysis were performed to determine risk factors of CLNM. A nomogram for predicting CLNM was developed, internal and external calibration was performed for the established model.

RESULTS

Variables (sex, chronic lymphocytic thyroiditis, tumor size, the number of foci, tumor location, margin) significantly associated with CLNM were included in the nomogram. The nomogram showed excellent calibration in the training group and validation group, with area under curves of 0.806 (95% CI, 0.771 to 0.825), and 0.799 (95% CI, 0.778-0.813) respectively.

CONCLUSION

Through this accurate and easy-to-use nomogram, the possibility of CLNM can be objectively quantified preoperatively. Clinicians can use this nomogram to evaluate the status of lymph nodes in PTC patients and consider prophylactic CND for those with high scores.

Nomogram Including Elastography for Prediction of Contralateral Central Lymph Node Metastasis in Solitary Papillary Thyroid Carcinoma Preoperatively

Background

It is controversial whether contralateral prophylactic central neck dissection (PCND) should be performed for patients with solitary and clinical lymph node negative (cN₀) papillary thyroid carcinoma (PTC) although routine ipsilateral PCND is required.

Objective

The aim of this study was to develop an improved nomogram including clinical features, ultrasound, and acoustic radiation force impulse (ARFI) elastography for the prediction of contralateral central lymph node metastasis (CLNM) in patients with solitary and cN₀ PTC in the preoperative period.

Materials and Methods

A total of 340 patients were retrospectively included as the training cohort and 170 patients as the external validation cohort. Patients were grouped according to the pathological results of contralateral CLNM. The association between the clinical characteristics, ultrasound, and ARFI elastography and the risk for contralateral CLNM were analyzed. A nomogram was established based on the result of multivariable logistic analysis to predict the risk of contralateral CLNM, which was assessed by internal and external validation.

Results

CLNM was found in 213 patients (41.8%), among whom 142 (27.8%) had ipsilateral CLNM and 95 (18.6%) had contralateral CLNM (including 68 (13.3%) with bilateral CLNM). Multivariable analysis revealed that patients with younger age, male gender, larger tumor size, closer distance from the capsule, microcalcification, and larger SWV_mean were independent predictors associated with the contralateral CLNM (P < 0.05), which was served as the basis of the nomogram. It showed good discrimination (C-index: 0.856) and calibration (χ² = 9.028, P = 0.340, Hosmer–Lemeshow test) in the training cohort, and good discrimination was maintained in the external validation cohort (C-index: 0.792).

Conclusion

The nomogram utilizing the features of ultrasound combined with ARFI elastography in preoperatively predicting the risk of contralateral CLNM in patients with solitary and cN₀ PTC was established, which showed superior performance both in internal and external validation.

The role of molecular genetics in the presurgical management of thyroid nodules

INTRODUCTION

Fine-needle aspiration (FNA) is an important diagnostic tool for the evaluation of thyroid nodules. However, in almost ¼ of all nodules submitted to FNA cytology is indeterminate. Since the majority of genetic alterations in thyroid cancer have been identified, the use of molecular testing platforms has been endorsed by American Thyroid Association for management of indeterminate nodules.

EVIDENCE ACQUISITION

Several commercial tests were based on mRNA expression of FNA samples (Afirma®, Veracyte, South San Francisco, CA, USA) while others detect DNA alterations (ThyroSeq, UPMC, Pittsburgh, PA, USA). Noncommercial tests detect limited number of point mutations or re-arrangements (gene panels). Literature study included a Pubmed research for adult original studies from 2003 to 2020, focusing on terms such as "molecular tests," "nodules with indeterminate AUS/FLUS and FN/SFN cytology."

EVIDENCE SYNTHESIS

Gene expression profile tests serve as "rule out" tests due to their high negative predictive value and perform better in a setting of low cancer pretest probability. Genetic alteration platforms display high positive predictive value and serve as rather "rule in" tests but their diagnostic accuracy is hampered either because a small proportion of nodules does not harbor any of these alterations targeted (gene panels) or because commonly identified RAS mutations can also be found in benign nodules.

CONCLUSIONS

Next generation sequencing development and incorporation of other genetic markers such as miRNA can improve diagnostic accuracy of molecular tests.

BRAF V600E and lymph node metastases in papillary thyroid cancer

OBJECTIVE

To evaluate the relationship between the BRAF V600E mutation in lymph node metastasis (LNM) and its invasive characteristics in papillary thyroid cancer (PTC).

MATERIAL AND METHODS

A total of 373 PTC patients were enrolled in this study conducted at Zhujiang Hospital of Southern Medical University between January 2017 and December 2018. PTCs with cervical lymph node metastases were verified pathohistologically, and primary tumors and LNM were examined for the BRAF V600E mutation. Patients were excluded from the study if the BRAF V600E mutation was examined only in primary tumors or only in LNM.

RESULTS

Of the 373 patients examined, BRAF V600E mutation frequency in primary tumors was slightly higher than in LNM (81.5% vs 78.0%, P = 0.000), the intra-class correlation coefficient (ICC) was 0.865 (95% CI 0.835-0.890). The BRAF V600E mutation in both primary tumor and LNM negatively correlated with the size of the largest metastatic focus of LNM (Odds ratio, OR = 0.297, 95% CI 0.143-0.616, P = 0.001; OR = 0.242, 95% CI 0.119-0.492, P = 0.000, respectively). There was no relationship between BRAF V600E mutation in LNM and the number, extranodal extension or stage of LNM (P > 0.05).

CONCLUSION

The BRAF V600E mutation in LNM may not be related to the invasive characteristics of LNM in PTC.

Risk stratification for lateral involvement in papillary thyroid carcinoma patients with central lymph node metastasis

PURPOSE

To effectively predict lateral neck lymph nodes (LLN) metastasis in papillary thyroid carcinoma (PTC) patients with central lymph nodes (CLN) invasion, and devise targeted treatment strategies.

METHODS

Four hundred and thirty-four PTC patients with CLN metastasis from two medical centers were retrospectively analyzed. A new statistical model was established for predicting LLN involvement in these patients to guide lymph nodes management strategies.

RESULTS

Patients with more than five positive CLN metastasis appeared to have extremely high risk (83.0%) of LLN involvement. For patients with five or less positive CLN invasion, multivariate logistic analyses were applied. Independent risk factors for LLN involvement were determined to be: age over 40, maximum tumor diameter of no less than 1.0 cm, existence of thyroid capsular invasion, and tumor with ipsilateral nodular goiter (iNG). These factors were used to construct a predictive nomogram. The accuracy and validity of our newly built model were verified by C-index 0.761 (95% CI, 0.707-0.815) in development cohort and 0.759 (95% CI, 0.745-0.773) in validation cohort and calibration curve. The patients were stratified into three groups based on their nomogram risk scores. Possible LLN involvement rates for low-risk, moderate-risk, and relatively high-risk subgroups were 8.9%, 22.8%, and 48.2%, respectively.

CONCLUSIONS

Our newly established model can effectively predict possible LLN metastasis in PTC patients, and a new strategy selection flow chart was created for patients with positive CLN invasion. For patients in high-risk group, prophylactic LLN dissection is recommended, if not, adjuvant radioactive iodine or a closer follow-up scheme should at least be conducted. For those in low-risk group, surgical intervention is unnecessary and regular follow-up is recommended.

The Association Between Lymph Node Stage and Clinical Prognosis in Thyroid Cancer

Purpose: To investigate the association between lymph node (N) stage and clinical outcome in thyroid cancer patients with initial distant metastasis. Methods: A total of 3,198 cases (1,435 males and 1,763 females) between 2004 and 2015 with initial distant metastasis were obtained from the surveillance, epidemiology, and end results (SEER) database. Patients with a median follow up time of 13 months and a median age of 66 years were analyzed. A total of 1,407 cases had detailed information regarding the four most common metastatic organs after the year 2010. Kaplan-Meier (KM) analyses, log-rank tests, Cox regression, and logistic regression analyses were used. Results: Among the whole cohort, 33.4% (1,069/3,198), 14.5% (464/3,198), 10.1% (322/3,198), 34.2% (1,094/3,198), and 7.8% (249/3,198) of the patients were at the stage of N0, NX, N1a, N1b, and N1NOS (referring to metastasis to regional lymph nodes but not otherwise specified), respectively. The KM curves demonstrated that the patients at the NX stage had the worst survival. The NX and N1b groups had the highest hazard ratios (HRs) of 1.83 (95%CI 1.46-2.31) and 1.78 (95%CI 1.52-2.10) after adjusting age, race, gender, and tumor size (p < 0.001) compared with N0 group. The lung was the most common metastatic site, with a rate of 51.2% (720/1,407). Compared with the N0 group, N1 patients had higher odds (OR 1.63, 95%CI 1.31-2.01, p < 0.001) for lung metastasis. Similar results were obtained in papillary thyroid cancer (PTC) sub-cohort. Conclusions: Overall, the TC patients at the NX stage had the highest mortality risk, followed by N1b, N1a, and N0 groups. Compared with N0 patients, N1 patients were more likely to have lung metastasis. The poor prognosis for TC patients with the NX stage may make more aggressive treatment reasonable.

Association Between BRAFV600E Mutation and the American College of Radiology Thyroid Imaging, Reporting and Data System in Solitary Papillary Thyroid Carcinoma

RATIONALE AND OBJECTIVES

The purpose of this study was to evaluate the associations between BRAF^V600E mutation, the American College of Radiology (ACR) thyroid imaging, reporting and data system (TI-RADS) on ultrasound and clinicopathological characteristics in patients with a solitary papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

This retrospective study included 397 patients with a solitary PTC, proved pathologically. BRAF^V600E mutation status was detected in postoperative samples by real-time fluorescent polymerase chain reaction. Associations of BRAF^V600E mutation with the ACR TI-RADS and clinicopathological characteristics were analyzed.

RESULTS

In this study, the incidence of BRAF^V600E mutation was 81.4% (323/397) in patients with a solitary PTC. Univariate analyses showed that BRAF^V600E mutation was significantly associated with margin, higher ACR TI-RADS point scores, and Hashimoto's thyroiditis. In multivariate analyses, lobulated or irregular margin was independently associated with BRAF^V600E mutation in total solitary PTC. Furthermore, both in total solitary PTC and papillary thyroid microcarcinoma, BRAF^V600E mutation was associated with ACR TI-RADS point scores, which was positively correlated with the risk of BRAF^V600E mutation. There was no significant relationship between BRAF^V600E mutation and ACR TI-RADS point scores in PTC >10 mm. In addition, Hashimoto's thyroiditis had a significant negative association with BRAF^V600E mutation.

CONCLUSION

A lobulated or irregular margin of the thyroid nodule is independently associated with BRAF^V600E mutation in patients with PTC. In addition, higher ACR TI-RADS point scores is an independent risk factor for BRAF^V600E mutation, and ACR TI-RADS point scores is positively associated with the risk of BRAF^V600E mutation in solitary PTC, especially in papillary thyroid microcarcinoma. Our findings may be helpful for preoperative identification and medical management of PTC patients with BRAF^V600E mutation.

BRAF mutation in papillary thyroid cancer-Prevalence and clinical correlation in a South-East Asian cohort

OBJECTIVE

BRAF mutation is the commonest mutation seen in papillary thyroid cancer (PTC), but its prevalence and clinical significance vary across countries. We aim to evaluate the prevalence and clinico-pathological correlation of BRAF mutation in PTC patients at our centre.

STUDY DESIGN

Retrospective cohort study of 75 consecutive archival thyroid specimens, whereby BRAF mutation was detected using a polymerase chain reaction (PCR) technique and correlated with clinical and pathological features and outcomes.

SETTING

Tertiary university hospital in Singapore.

PARTICIPANTS

A total of 75 consecutive histologically proven archival thyroid specimens from patients who underwent thyroidectomy for PTC were accrued for this study.

MAIN OUTCOME MEASURES

Main outcome is to determine the prevalence of the BRAF mutation in our South-East Asian population. Secondary aim is to correlate the mutational status with adverse pathological features like histological variants, multi-focality, lymphovascular invasion and extra-thyroidal extension, clinical features like demographics, TNM stage, recurrence and survival, as well as treatment details like type of surgery performed and radioiodine doses.

RESULTS

BRAF mutation was detected in 56% (42/75) of PTC. All but one BRAF-mutated PTC had the BRAFV600E mutation. BRAF-mutated tumours were associated with an advanced T-stage (P = 0.049) and were more likely to have a central neck dissection (P = 0.036). There was no significant correlation between BRAF mutation status and clinical outcomes.

CONCLUSION

The prevalence of BRAF mutation is 56%. BRAF mutation-positive tumours were associated with locally advanced disease, but not poorer survival.

Establishing a prediction model for lateral neck lymph node metastasis in patients with papillary thyroid carcinoma

This study aimed to establish a model for predicting lateral neck lymph node metastasis in patients with papillary thyroid carcinoma. A total of 106 patients with papillary thyroid carcinoma undergoing initial treatment of neck lymph node dissection (including central and lateral neck lymph nodes) at the thyroid surgery department were enrolled from January 2009 to April 2017. Logistic regression analysis was used to screen the factors influencing lateral neck lymph node metastasis and develop a prediction model. The receiver operating characteristic curve was used to evaluate the predictive power and boundary value of the model for lateral neck lymph node metastasis. Prediction model: Logistic(P) = -5.699 + 0.681 × _(TSH) + 0.342 × _{(Metastatic rate of central lymph nodes)} + 1.463 × _{(Combined with Hashimoto's disease)} + 1.525 × _{(Number of tumors)}. When logistic (P) was ≥ 0.821, it was predicted that lateral neck lymph node metastasis occurred in patients with papillary thyroid carcinoma. When logistic (P) was <0.821, it was predicted that no metastasis was found in the lateral neck lymph node. The prediction accuracy was 78.3%. The model helped in evaluating lateral neck lymph node metastasis in patients with papillary thyroid carcinoma. Also, it had significance in determining reasonable surgical range, reducing unnecessary lateral neck lymph node dissection, and further improving the quality of life of patients.

Predictive Value of BRAFV600E Mutation for Lymph Node Metastasis in Papillary Thyroid Cancer: A Meta-analysis

BRAF^V600E mutation has been thought to be a valuable molecular marker that may predict a worse prognosis for papillary thyroid cancer (PTC). But whether BRAF^V600E mutation is associated with lymph node metastasis (LNM) remains controversial. Different surgical strategies may bring a bias in demonsstrating the association between them. In order to delineate a risk stratification to guide a tailored initial approach to tumors that express BRAF^V600E mutation, we performed this meta-analysis by using the articles in which total or near-total thyroidectomy plus bilateral central lymph node dissection was routinely performed to avoid the bias from the surgical strategy. We searched the Medline, Embase and CNKI database for eligible studies from January 2003 to May 2018. Meta-analysis was performed using the STATA 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated under fixed-effects or randomeffects models. Fifteen clinical studies were included with a total of 4909 PTC patients. Our meta-analysis results reported that BRAFV600E mutation was associated with LNM (OR=1.34; 95% CI: 1.09-1.65; P=0.005), as well as central LNM (OR=1.59; 95% CI: 1.35-1.88; P<0.00001). Moreover, in patients with papillary thyroid microcarcinoma, we also confirmed the predictive value of BRAF^V600E mutation for LNM (OR=3.49; 95% CI: 2.02-6.02; P<0.00001). This meta-analysis demonstrates that BRAF^V600E mutation is closely related to LNM in PTC patients. The results suggest that BRAF^V600E mutation can be considered as a risk factor for LNM in PTC. Moreover, combining BRAF^V600E mutation with other risk factors to determine the initial surgical treatment may bring benefits for PTC patients.

Nomogram for predicting central lymph node metastasis in papillary thyroid microcarcinoma: A retrospective cohort study of 8668 patients

INTRODUCTION

The status of central lymph node metastasis (CLNM) is crucial to determining the surgical strategies for papillary thyroid micro carcinoma (PTMC). The objective of the study was to establish a nomogram to predict the possibility of CLNM in PTMC patients.

METHODS

A total of 8668 PTMC patients who underwent total thyroidectomy or lobectomy with central lymph node dissection (CLND) from 2006 to 2016 were retrospectively retrieved. Univariate and multivariate analysis were performed to examine risk factors associated with CLNM. A nomogram for predicting CLNM was established and internally validated.

RESULTS

Six variables significantly associated with CLNM were included in our model, these are age <55 years (odd ratio [OR] = 1.779, 95% confidence interval [CI],1.569-2.017; P < 0.001), male sex (OR = 1.718, 95%CI,1.543-1.913; P < 0.001), tumor size 0.5-1.0 cm (OR = 1.985,95%CI,1.761-2.238; P < 0.001), multifocal lesions (OR = 1.263, 95%CI,1.118-1.426; P < 0.001), extra thyroidal extension (ETE) (OR = 1.348, 95%CI,1.092-1.664; P = 0.005) and lateral lymph node metastasis (LLNM) (OR = 5.135, 95%CI, 4.236-6.225; P < 0.001). The discrimination of the prediction model was 0.711 (95%CI, 0.700-0.722; P < 0.001).

CONCLUSIONS

Based on the quantified risk stratification offered by our nomogram, clinicians might have a thorough discussion with PTMC patients during the both pre- and postoperative period. Prophylactic CLND and strict postoperative evaluation may be indicated when the patients have a high nomogram score.

Association between BRAF V600E Mutation and Ultrasound Features in Papillary Thyroid Carcinoma Patients with and without Hashimoto's Thyroiditis

To assess the association between BRAF V600E mutation and ultrasound (US) features in papillary thyroid carcinoma (PTC) patients with and without Hashimoto’s thyroiditis (HT). We retrospectively reviewed the US features and status of BRAF V600E mutation in 438 consecutive patients with surgically confirmed PTCs. The association between BRAF mutation and US features were analyzed. In addition, we conducted subgroup analyses in terms of coexistent HT. The BRAF mutation was found in 86.5% of patients (379 of 438). Patient age (OR: 1.028, P = 0.010), age ≥ 50 y (OR: 1.904, P = 0.030), and microcalcification (OR: 2.262, P = 0.015) on US were significantly associated with BRAF mutation in PTC patients. Solid component (OR: 5.739, P = 0.019) on US was the significant predictor for BRAF mutation in patients with HT, while age (OR: 1.036, P = 0.017) and microcalcification (OR: 3.093, P = 0.017) were significantly associated with BRAF mutation in patients without HT. In conclusion, older age and microcalcification are risk factors for BRAF mutation in PTC patients, especially in those without HT. For those with HT, however, PTCs with BRAF mutation tend to be solid on ultrasound. These factors might be considered when making treatment planning or prognosis evaluation.

Predictive Factors of Lymph Node Metastasis in Follicular Variant of Papillary Thyroid Carcinoma

BACKGROUND

Compared with conventional papillary thyroid carcinoma (PTC), follicular variant of PTC (FV-PTC) shows less aggressive behavior and better prognosis. Nonetheless, regional lymph node (LN) metastasis was found in 22.8% of FV-PTC patients. Because LN metastasis is a proven predictor of recurrence in PTC, it is important to assess LN metastasis in FV-PTC patients.

METHODS

We retrospectively reviewed 134 FV-PTC patients who underwent thyroidectomy with neck dissection.

RESULTS

Central LN metastasis (CLNM) and lateral LN metastasis (LLNM) were found in 50 (37.3%) and 16 (11.9%) patients, respectively. In the multivariate analysis for CLNM, male sex (adjusted OR 4.735, p = 0.001), nonencapsulated form (adjusted OR 2.863, p = 0.022), and tumor size >1.0 cm (adjusted OR 3.157, p = 0.008) were independent predictors of high prevalence of CLNM in FV-PTC patients. In the multivariate analysis for LLNM, microscopic extrathyroidal extension (ETE) (adjusted OR 3.939, p = 0.041) and CLNM (adjusted OR 13.340, p = 0.001) were independent predictors of high prevalence of LLNM in FV-PTC patients.

CONCLUSIONS

Meticulous perioperative evaluation and prophylactic central neck dissection may be beneficial for FV-PTC patients with male sex, nonencapsulated form, and tumor size >1.0 cm. Moreover, cautious perioperative evaluation of lateral neck LN may be mandatory for FV-PTC patients with microscopic ETE and CLNM.

The Role of Central Neck Lymph Node Dissection in the Management of Papillary Thyroid Cancer

Papillary thyroid cancer (PTC) is the most common thyroid malignancy, and cervical nodal metastases are frequent at presentation. The most common site for nodal metastases from PTC is the central compartment of the ipsilateral neck in the paratracheal and pretracheal regions. The decision to resect these lymph nodes at the time of thyroidectomy often depends on if nodes with suspected malignancy can be identified preoperatively. If nodal spread to the central neck nodes is known, then the consensus is to remove all nodes in this area. However, there remains significant controversy regarding the utility of removing central neck lymph nodes for prophylactic reasons. Herein, we review the potential utility of central neck lymph node dissection as well as the risks of performing this procedure. As well, we review the potential of molecular testing to stratify patients who would most benefit from this procedure. We advocate a selective approach in which patients undergo clinical neck examination coupled with ultrasound to detect any concerning lymph nodes that warrant additional evaluation with either fine needle aspiration or excisional biopsy in the operating room. In lieu of clinical lymphadenopathy, we suggest the use of patient and disease characteristics as identified by multiple groups, such as the American Thyroid Association and European Society of Endocrine Surgeons, which include extremes of ages, large primary tumor size, and male gender, when deciding to perform central neck lymph node dissection. Patients should be educated on the potential long-terms risks versus the lack of known long-term benefits.

The role of molecular diagnostic testing in the management of thyroid nodules

INTRODUCTION

Fine needle aspiration (FNA) with cytologic examination remains the standard of care for investigation of thyroid nodules. However, as many as 30% of FNA samples are cytologically indeterminate for malignancy, which confounds clinical management. To reduce the burden of repeat diagnostic testing and unnecessary surgery, there has been extensive investigation into molecular markers that can be detected on FNA specimens to more accurately stratify a patient's risk of malignancy. Areas covered: In this review, the authors discuss recent evidence and progress in molecular markers used in the diagnosis of thyroid cancer highlighting somatic gene alterations, molecular technologies and microRNA analysis. Expert commentary: The goal of molecular markers is to improve diagnostic accuracy and aid clinicians in the preoperative management of thyroid lesions. Modalities such as direct mutation analysis, mRNA gene expression profiling, next-generation sequencing, and miRNA expression profiling have been explored to improve the diagnostic accuracy of thyroid nodule FNA. Although no perfect test has been discovered, molecular diagnostic testing has revolutionized the management of thyroid nodules.

A meta-analysis of prognostic roles of molecular markers in papillary thyroid carcinoma

The prognostic role of molecular markers in papillary thyroid carcinoma (PTC) is a matter of ongoing debate. The aim of our study is to investigate the impact of RAS, BRAF, TERT promoter mutations and RET/PTC rearrangements on the prognosis of PTC patients. We performed a search in four electronic databases: PubMed, Scopus, Web of Science and Virtual Health Library (VHL). Data of hazard ratio (HR) and its 95% confidence interval (CI) for disease-specific survival (DSS) and disease-free survival (DFS) were directly obtained from original papers or indirectly estimated from Kaplan-Meier curve (KMC). Pooled HRs were calculated using random-effect model weighted by inverse variance method. Publication bias was assessed by using Egger's regression test and visual inspection of funnel plots. From 2630 studies, we finally included 35 studies with 17,732 patients for meta-analyses. TERT promoter mutation was significantly associated with unfavorable DSS (HR = 7.64; 95% CI = 4.00-14.61) and DFS (HR = 2.98; 95% CI = 2.27-3.92). BRAF mutations significantly increased the risk for recurrence (HR = 1.63; 95% CI = 1.27-2.10) but not for cancer mortality (HR = 1.41; 95% CI = 0.90-2.23). In subgroup analyses, BRAF mutation only showed its prognostic value in short-/medium-term follow-up. Data regarding RAS mutations and RET/PTC fusions were insufficient for meta-analyses. TERT promoter mutation can be used as an independent and reliable marker for risk stratification and predicting patient's outcomes. The use of BRAF mutation to assess patient prognosis should be carefully considered.

The utility of the Bethesda category and its association with BRAF mutation in the prediction of papillary thyroid cancer stage

PURPOSE

This study aims to determine the utility of the Bethesda category and its association with BRAF mutation in prediction of the papillary thyroid cancer (PTC) stage.

METHODS

A prospective study analyzed patients who had ultrasound-suspicious thyroid nodules, underwent FNA and cytological examination, and were classified according to the Bethesda system. Patients from Undetermined Significance Or Follicular Lesion Of Undetermined Significance (AUS/FLUS), Follicular Neoplasm or Suspicious for a Follicular Neoplasm (FN/SFN), Suspicious for Malignant Cells (SMC), and Positive for Malignant Cells (PMC) groups were examined for the BRAF mutation and had a thyroid surgery. Demographical and histological features and stage of the disease were evaluated for PTC patients in accordance with the Bethesda category and its association with BRAF mutation.

RESULTS

Three hundred eight of all patients underwent operation. One hundred forty-three (46.4%) of them were diagnosed with PTC. In 14 (9.8%) PTC cases, FNA biopsies were classified as AUS/FLUS, 23 (16.1%) as FN/SFN, 41 (28.7%) as SMC, and 65 (45.5%) as PMC. I-II stages of PTC were diagnosed for 88 (61.5%) patients and III-IVA for 55 (38.5%). Patients from the SMC and PMC groups had larger tumors, higher incidence of lymph node metastases, classical PTC type, B-type Raf (BRAF) positive, and III-IVA stage cancer, than patients from the AUS/FLUS and FN/SFN groups. When comparing 27 (18.9%) BRAF-negative patients from the AUS/FLUS and FN/SFN groups with 116 (81.1%) BRAF-negative patients from the SMC and PMC groups and all BRAF-positive patients, the prediction of more aggressive histological features and stage was slightly improved.

CONCLUSIONS

Higher Bethesda categories are associated with higher stages of PTC. Association of the Bethesda category with BRAF mutation can slightly improve the value of stage prediction.

Predictive Factors for Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

BACKGROUND

Because lymph node (LN) metastasis has been proven to be a predictor for locoregional recurrence (LRR) in papillary thyroid microcarcinoma (PTMC), better knowledge about the predictors for LN metastasis in PTMC is required.

METHODS

We retrospectively reviewed 5656 PTMC patients who underwent total thyroidectomy and central neck dissection and/or lateral neck dissection between January 1997 and June 2015.

RESULTS

Male gender (adjusted odds ratio [OR] 2.332), conventional variant (adjusted OR 4.266), tumor size >0.5 cm (adjusted OR 1.753), multiplicity (adjusted OR 1.168), bilaterality (adjusted OR 1.177), and extrathyroidal extension (ETE) (adjusted OR 1.448) were independent predictors for high prevalence of central LN metastasis (CLNM), whereas per 10-year age increment (adjusted OR 0.760) and chronic lymphocytic thyroiditis (adjusted OR 0.791) were independent predictors for low prevalence of CLNM. In addition, male gender (adjusted OR 1.489), tumor size >0.5 cm (adjusted OR 1.295), multiplicity (adjusted OR 1.801), ETE (adjusted OR 1.659), and CLNM (adjusted OR 4.359) were independent predictors for high prevalence of lateral LN metastasis (LLNM), whereas per 10-year age increment (adjusted OR 0.838) was an independent predictor for low prevalence of LLNM. There was a statistically significant difference in LRR with regard to nodal stage (p < 0.001).

CONCLUSIONS

Meticulous perioperative evaluation of LN metastasis is required for PTMC patients with the above predictors.

Chronic lymphocytic thyroiditis and BRAF V600E in papillary thyroid carcinoma

It has been reported that papillary thyroid carcinoma (PTC) with chronic lymphocytic thyroiditis (CLT) is less associated with extrathyroidal extension (ETE), advanced tumor stage and lymph node (LN) metastasis. Other studies have suggested that concurrent CLT could antagonize PTC progression, even in BRAF-positive patients. Since the clinical significance of the BRAF mutation has been particularly associated with conventional PTC, the purpose of this study was to determine the clinical significance of CLT according to BRAF mutation status in conventional PTC patients. We retrospectively reviewed the medical records of 3332 conventional PTC patients who underwent total thyroidectomy with bilateral central neck dissection at the Thyroid Cancer Center of Samsung Medical Center between January 2008 and June 2015. In this study, the prevalence of BRAF mutation was significantly less frequent in conventional PTC patients with CLT (76.9% vs 86.6%). CLT was an independent predictor for low prevalence of ETE in both BRAF-negative (OR=0.662, P=0.023) and BRAF-positive (OR=0.817, P=0.027) conventional PTC patients. In addition, CLT was an independent predictor for low prevalence of CLNM in both BRAF-negative (OR=0.675, P=0.044) and BRAF-positive (OR=0.817, P=0.030) conventional PTC patients. In conclusion, BRAF mutation was significantly less frequent in conventional PTC patients with CLT. However, CLT was an independent predictor for less aggressiveness in conventional PTC patients regardless of BRAF mutation status.

Mutation Profile of Well-Differentiated Thyroid Cancer in Asians

Recent advances in molecular diagnostics have led to significant insights into the genetic basis of thyroid tumorigenesis. Among the mutations commonly seen in thyroid cancers, the vast majority are associated with the mitogen-activated protein kinase pathway. B-Raf proto-oncogene (BRAF) mutations are the most common mutations observed in papillary thyroid cancers (PTCs), followed by RET/PTC rearrangements and RAS mutations, while follicular thyroid cancers are more likely to harbor RAS mutations or PAX8/peroxisome proliferator-activated receptor γ (PPARγ) rearrangements. Beyond these more common mutations, alterations in the telomerase reverse transcriptase (TERT) promoter have recently been associated with clinicopathologic features, disease prognosis, and tumorigenesis in thyroid cancer. While the mutations underlying thyroid tumorigenesis are well known, the frequency of these mutations is strongly associated with geography, with clear differences reported between Asian and Western countries. Of particular interest is the prevalence of BRAF mutations, with Korean patients exhibiting the highest rate of BRAF-associated thyroid cancers in the world. Here, we review the prevalence of each of the most common mutations in Asian and Western countries, and identify the characteristics of well-differentiated thyroid cancer in Asians.