Analysis of differential BRAF(V600E) mutational status in multifocal papillary thyroid carcinoma: evidence of independent clonal origin in distinct tumor foci

Multifocal Papillary Thyroid Carcinomas With Discordant Molecular Drivers: Emphasizing the Morphology and Collision Tumors

Multifocal papillary thyroid carcinomas (PTCs) are common and the majority of the tumors harbor mutual BRAF p.V600E mutation. This study aimed to investigate a contemporary series of multifocal PTCs with discordant molecular drivers. Consecutive thyroidectomies diagnosed with multifocal PTCs ≥0.5 cm between 2019 and 2023 were reviewed. Immunohistochemistry (IHC) for BRAF VE1 was performed for all tumors. Cases with discordant BRAF IHC results or morphologic discrepancy were identified, and BRAF IHC-negative tumors were subjected to RAS Q61R IHC and/or targeted RNA next-generation sequencing. A total of 770 patients with a main PTC ≥0.5 cm were identified; 255 (33.1%) had multifocal disease, and 142 (18.4%) had at least another PTC ≥0.5 cm. Among them, 13 cases (9.2%, 13/142) had discordant molecular drivers. Twelve cases had one or more BRAF -positive PTCs accompanied by a BRAF -negative PTC (3 with CCDC6::RET fusion, 1 with NCOA4::RET fusion, 1 with ACBD5::RET fusion, 2 with ETV6::NTRK3 fusion, 1 with TG::FGFR1 fusion, 1 with LMTK2::BRAF fusion, 1 with AGK::BRAF fusion and RAS p.Q61R mutation, 1 with RAS p.Q61R mutation, and 1 without detectable molecular drivers). The last case had tumors with discordant fusion drivers ( VIM::NTRK3 and TNS1::BRAF ). Most cases showed tumors that were morphologically distinct (92.3%, 12/13) and occurred in the contralateral lobes (76.9%, 10/13). Notably, we identified 4 cases (30.8%) that presented as collision tumors and 6 cases (46.2%) that showed lymph node metastases, including 2 with simultaneous involvement by tumors with discordant molecular drivers, as novel findings. In summary, a subset (9.2%) of multifocal PTCs had discordant molecular drivers and 84.6% of them were a combination of BRAF -positive and kinase gene fusion-associated PTCs, most with distinct morphologies. Almost half of the cases had nodal metastasis and a third of them showed simultaneous involvement by tumors with discordant molecular drivers. The results highlight the clinical importance of identifying such cases, given the potentially different treatments.

Analysis of the clonal origin and differences in the biological behavior of multifocal papillary thyroid carcinoma

Papillary thyroid carcinoma (PTC) exhibits a trend of multifocal growth. However, the clonal origin of multiple cancer foci in the thyroid gland remains an issue of ongoing debate. In order to investigate the clonal origin and biological behavior differences of multifocal PTC (MPTC) from a unique perspective, a combination of dual gene and dual protein detection methods was used. The present study included 52 patients with MPTC. Immunohistochemical staining was used to assess the expression of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) and telomerase reverse transcriptase (TERT) proteins, while quantitative PCR and Sanger sequencing were used to identify BRAF and TERT gene mutations. Based on the results, MPTC cases were classified into two clonal origins, namely intraglandular metastatic (71.2%) and independent multicentric origin (28.8%). BRAF protein expression and BRAF gene mutation were significantly higher in the intraglandular metastasis group than in the multicentric cancer group. However, no significant differences in TERT protein expression and TERT gene mutation were observed between the two groups. Sex, central lymph node metastasis rate, Hashimoto's thyroiditis and tumor distribution laterality were not found to differ significantly between the two groups. However, significant differences were detected in age at initial diagnosis, lateral cervical lymph node metastasis rate, tumor capsule invasion rate and maximum tumor diameter. The study found that MPTC predominantly occurs due to intraglandular metastasis, which is associated with stronger tumor invasiveness than cancer foci with multiple independent origins, as it is more likely to exhibit pathogenic gene mutations and abnormal protein expression, cervical lymph node metastasis and capsule invasion. Therefore, it is recommended that the surgical approaches and follow-up strategies for intraglandular metastatic MPTC should be aggressive and individualized.

Bilateral papillary thyroid cancer: pitfalls of ACR TI-RADS and evaluation of modified parameters

PURPOSE

To explore modified parameters of the American College of Radiology Thyroid Imaging Reporting and Data System (TI-RADS) for evaluating contralateral nodules based on preoperative ultrasound features of papillary thyroid carcinoma (PTC) in the suspected lobe, thus guiding the management of bilateral PTC.

METHODS

We retrospectively analyzed 389 consecutive patients with PTC (272 in training set, 117 in validation set) who underwent total thyroidectomy from March 2020 to March 2022. According to their postoperative pathological data, the patients were divided into unilateral and bilateral PTC groups. The clinicopathological features and sonographic characteristics of suspected nodules were compared between the groups, and further ultrasonic characteristics of TI-RADS grade (TR grade)-underestimated nodules were analyzed.

RESULTS

Patients with a body mass index of ≥25 kg/m2 (P < 0.001), multifocality in the suspected lobe (P < 0.001), and TR > 3 isthmus nodules (P = 0.003) tended to have bilateral PTC. After modifying the TI-RADS classification for contralateral nodules using these three parameters, the area under the curve for diagnosing contralateral lesions increased from 0.79 (95% confidence interval, 0.74-0.84) to 0.83 (0.78-0.87) in the training set. The missed diagnosis rate of contralateral PTC decreased in both the training set [21.1% (28/133) to 4.5% (6/133)] and validation set [11.4% (8/70) to 2.9% (2/70)]. Preoperative ultrasound tended to underestimate the contralateral nodules with the presence of cystic components [100% (6/6)] and halo sign [73.3% (11/15)].

CONCLUSION

The modified TI-RADS classification based on the suspected lobe may facilitate effective preoperative malignant risk stratification of contralateral nodules in bilateral PTC.

Multi-UniFocality (MUF), in contrast to multifocality, in thyroid lesions: Relation to lymphocytic thyroiditis

Whereas multifocality typically concerns papillary thyroid carcinoma (PTC) without specification of intrathyroidal metastatic or independent nature of tumor foci, the designation of the latter as Multi-UniFocal (MUF) may be relevant for select cases. A case series involving multifocal thyroid lesions with divergent histopathological morphology and/or molecular profile, with molecular evaluation of multiple individual tumor foci per patient based on a next-generation sequencing approach, was retrospectively reviewed. Twenty-five patient cases with multifocal thyroid lesions suggestive of MUF, with 2-6 (median 3) tumor foci per patient, were described. Tumor lesions comprised diverse histopathology, including PTC, (E)FVPTC, NIFTP, FA, FTC, and oncocytic. Morphologically similar and/or diverse tumor foci harbored different molecular alterations (suggestive of non-shared clonality); with(out) coexistent similar foci harboring identical molecular alterations; or (partly) shared molecular alterations. MUF was associated with chronic lymphocytic thyroiditis in almost half of the cases. The recognition of MUF may justify the independent clinical consideration per individual tumor focus; as separate lesions albeit within a multifocal context. The potential clinical relevance and prognostic value of MUF remain to be further established.

Risks of central lymph node metastasis in papillary thyroid carcinoma with or without multifocality in at least one lobe: A multi-center analysis

PURPOSES

To quantitatively predict central lymph node metastasis (CLNM) risks by comparing the clinicopathological features of different multifocal manifestations in papillary thyroid carcinomas (PTC) patients.

METHODS

A total of 998 PTC patients from three medical centers were retrospectively analyzed.

RESULTS

PTC patients with multifocal lesions in at least one thyroid lobe (MF group) yielded significantly higher CLNM rates than those with unifocal lesions in one or both lobes (UF group). Multifocality in at least one lobe rather than bilateral presence was confirmed to be an independent risk factor of CLNM for PTC patients. Four (age, gender, maximum tumor diameter, and thyroid capsular invasion (TCI)) and three (age, gender, and TCI) factors were proven to be independent risk factors of CLNM for patients within UF and MF groups, respectively. Predictive nomograms were established for these patients based on their respective high-risk factors. The accuracy and validity of these newly-created models were verified using C-index and calibration curves. Patients within UF and MF groups possessing significantly different CLNM risks based on individualized nomogram risk scores were further classified into different subgroups. A detailed CLNM risk stratification flow chart covering all PTC patients was then established.

CONCLUSION

A meticulous evaluating system that quantifiesCLNM risk for PTC patients with unifocal lesions in one or both lobes and multifocal lesions in at least one lobe was established.

Bilateral follicular variant of papillary thyroid cancer with different RAS mutations detected with next-generation sequencing: Report of an unusual case and literature review

Multifocality in papillary thyroid carcinoma (PTC) is a common finding, but the clonal relationship between individual tumors remains uncertain. While multiple synchronous tumor foci of PTC may develop through permeation of intraglandular lymph vessels of a single malignant clone, they can also arise from independent progenitor clones sustained by different genetic events. We report the case of a 37‐year‐old man who underwent total thyroidectomy after fine‐needle aspiration of two bilateral thyroid nodules that yielded cytological findings consistent with atypia of undetermined significance/follicular lesion of undetermined significance. By next‐generation sequencing of a large panel of thyroid carcinoma related genes, we found that the larger tumor harbored a mutation of the NRAS gene, while the contralateral tumor harbored a different mutation in the HRAS gene. Final pathology of the surgical specimen showed two encapsulated follicular variant papillary thyroid carcinomas of 16 and 6 mm in the right and the left lobes, respectively. To the best of our knowledge, this is the fourth case of multifocal PTC showing different HRAS and NRAS mutations, and highlights that mutational heterogeneity is also present in non‐BRAF, non‐RET genes, supporting the hypothesis that independent progenitor clones may explain multifocality in papillary thyroid carcinoma.

Validation of Ultrasound Risk Stratification Systems for Cervical Lymph Node Metastasis in Patients with Thyroid Cancer

Simple Summary

Ultrasound (US) malignancy risk stratification systems (RSS) for cervical lymph nodes (LNs) have not been fully established in patients with thyroid cancer. In this study, we assessed the malignancy risks of each US feature and risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA). Both systems effectively classified malignancy risks; however, 15.1% of LNs were unclassifiable in ETA RSS. Suspicious US features of hyperechogenicity, cystic change, echogenic foci, and abnormal vascularity were independently associated with metastasis. When the primary tumor characteristics were assessed, tumor multiplicity was associated with metastasis in the indeterminate LN group. We refined this system and proposed an RSS based on the KSThR system for cervical LNs in patients with thyroid cancer.

Abstract

A malignancy risk stratification system (RSS) for cervical lymph nodes (LNs) has not been fully established. This study aimed to validate the current RSS for the diagnosis of cervical LN metastasis in thyroid cancer. In total, 346 LNs from 282 consecutive patients between December 2006 and June 2015 were included. We determined the malignancy risk of each ultrasound (US) feature and performed univariable and multivariable logistic regression analyses. Each risk category from the Korean Society of Thyroid Radiology (KSThR) and the European Thyroid Association (ETA) was applied to calculate malignancy risks. The effects of size, number of suspicious features, and primary tumor characteristics were analyzed to refine the current RSS. Suspicious features including echogenic foci, cystic change, hyperechogenicity, and abnormal vascularity were independently predictive of malignancy (p ≤ 0.045). The malignancy risks of probably benign, indeterminate, and suspicious categories were 2.2–2.5%, 26.8–29.0%, and 85.8–87.4%, respectively, according to the KSThR and ETA criteria. According to the ETA criteria, 15.1% of LNs were unclassifiable. In indeterminate LNs, multiplicity of the primary tumor was significantly associated with malignancy (odds ratio, 6.53; p = 0.004). We refined the KSThR system and proposed a US RSS for LNs in patients with thyroid cancer.

Prevalence and predictor for malignancy of contralateral thyroid nodules in patients with unilateral PTMC: a systematic review and meta-analysis

BACKGROUND

The presence of clinically negative nodules on the contralateral lobe is common in patients with unilateral papillary thyroid microcarcinoma (PTMC). The appropriate operational strategies of contralateral thyroid nodules remain controversial. In this study, we analyzed clinical features that could be predictors for malignancy of contralateral thyroid nodules coexisting with diagnosed unilateral PTMC.

METHODS

The literatures published from January 2000 to December 2019 were searched in PubMed, Cochrane Library, Embase, Web of Science, CNKI, and Wan Fang database. Odds ratio (OR) with 95% CI was used to describe categorical variables. Heterogeneity among studies was examined by the Q test and I2 test; potential publication bias was detected by Harbord test and 'trim and fill' method.

RESULTS

In this meta-analysis, 2541 studies were searched and 8 studies were finally included. The results showed that the rate of carcinoma in contralateral nodules was 23% (OR = 0.23, 95% CI = 0.18-0.29). The pooled data indicated that contralateral malignancy was not associated with age, gender, primary lesion size, ipsilateral central lymph node metastasis and multifocality of contralateral lesion. The following variables have correlations with an increased risk of contralateral malignancy: multifocality of primary carcinomas (OR = 3.93, 95% CI = 2.70-5.73, P < 0.0001), capsular invasion (OR = 1.61, 95% CI = 1.10-2.36, P = 0.01), and Hashimoto's thyroiditis (OR = 1.57, 95% CI = 1.13-2.20, P = 0.008).

CONCLUSIONS

Based on our meta-analysis, the rate at which contralateral malignancies are preoperatively misdiagnosed as benign is 23%. The risk factors for contralateral malignancy in unilateral PTMC patients with contralateral clinical negative nodules include multifocality of primary carcinomas, capsular invasion, and Hashimoto's thyroiditis.

The clinical importance of multifocality on tumor recurrence in papillary thyroid carcinoma

Background

Although the origin of the multifocality of papillary thyroid carcinoma (PTC) is unclear, it is not unusual and has not been considered as an independent prognostic factor from several tumor staging systems. This study aims to evaluate whether the presence of multifocality is associated with PTC recurrence.

Methods

We reviewed retrospectively detailed histological reports of PTC patients who underwent thyroidectomy from January 2000 through December 2010 at a single institution. We assessed the relationship between multifocality and other possible prognostic factors using binary logistic regression analysis. We compared recurrence by the Kaplan-Meier method (the log-rank test). We analyzed a prognostic factor for recurrence using Cox's proportional hazard model (the stepwise forward method).

Results

We enrolled a total of 434 PTC patients (380 women and 54 men; mean age, 48 years). The median follow-up period was 10.2 years. Of all PTC patients enrolled, 135 patients (31%) had multifocal PTC. There was a significant association between multifocality and cervical lymph node (CLN) metastasis (P=0.01). Multivariate analyses showed a significant association between multifocality and CLN metastasis (P<0.001). Multifocal PTC patients had higher CLN metastasis and tumor recurrence than those with single PTC. There was a significant association between multifocality and tumor recurrence (P=0.03 by log-rank test), but it disappeared in multivariate analysis.

Conclusions

Multifocality of PTC might be related to CLN metastasis and tumor recurrence.

The Extent of Therapeutic Central Compartment Neck Dissection in Unilateral cT1N1a or cT2N1a Papillary Thyroid Carcinoma

Purpose

Papillary thyroid carcinomas (PTCs) frequently metastasize to the central neck compartment. Therapeutic central compartment neck dissection (CCND) is a well-established treatment for PTC nodal metastases; however, the extent to which therapeutic CCND should be performed remains controversial. In this study, we investigated the predictive risk factors for contralateral paratracheal lymph node metastasis (LNM) in unilateral cT1N1a or cT2N1a PTC.

Patients and Methods

In this case–control study, which was conducted at a single center, demographic and pathological data from unilateral cT1N1a or cT2N1a PTC patients were collected from January 2017 to March 2019. All patients were treated with total thyroidectomy and bilateral CCND.

Results

Two hundred thirty-seven patients met the inclusion criteria. Forty-nine patients (20.7%) were diagnosed with positive lymph nodes in the contralateral paratracheal region. Male sex (p=0.003), T2 disease (21–40 mm) (p<0.001), inferior pole tumor (p=0.011), near isthmus tumor (p<0.001), aggressive pathology (p<0.001), intraglandular dissemination (p=0.009), pretracheal LNM (p<0.001), >5 metastatic lymph nodes (p<0.001) and extranodal invasion (p=0.003) were significantly associated with contralateral paratracheal LNM in univariate analysis. Multivariate analysis showed that male sex (p=0.005, OR=17.545), T2 disease (p=0.003, OR=34.317), inferior pole tumor (p=0.022, OR=8.289), near isthmus tumor (p=0.001, OR=40.229), aggressive pathology (p=0.027, OR=48.063), pretracheal LNM (p=0.002, OR=14.235) and >5 metastatic lymph nodes (p=0.025, OR=23.426) were independent risk factors for contralateral paratracheal LNM.

Conclusion

Male sex, T2 disease, a tumor located near the isthmus or inferior pole, aggressive pathology, pretracheal LNM and >5 metastatic lymph nodes were predictive factors for contralateral paratracheal LNM in unilateral cT1N1a or cT2N1a PTC. These data may be useful to identify targets for surveillance or develop therapeutic interventions for patients with CCND.

Management of cN0 papillary thyroid microcarcinoma patients according to risk-scoring model for central lymph node metastasis and predictors of recurrence

BACKGROUND

The role of routine prophylactic central neck dissection (pCND) in clinically lymph node-negative (cN0) papillary thyroid microcarcinoma (PTMC) patients remains controversial. This retrospective study aimed to identify the clinical and pathologic factors of central lymph node metastasis (CLNM) and recurrence in PTMC patients.

METHODS

A total of 371 cN0 PTMC patients from two hospitals were retrospectively analyzed. All patients underwent thyroidectomy plus pCND between January 2010 and January 2018. Clinicopathological features were collected, univariate and multivariate analyses were performed to determine the risk factors of CLNM. A scoring model was constructed on the basis of the results of independent risk factors of CLNM. The Cox proportional hazards model was used to analyze the risk factors of recurrence.

RESULTS

CLNM occurred in 123 (33.2%) patients. Multivariate analysis showed male, tumor size > 0.75 cm, multifocality, extrathyroidal extension (ETE) and tumor in the middle/lower pole were independent risk predictors of CLNM (P < 0.05). A seven-point risk-scoring model was established to predict the stratified CLNM in cN0 PTMC patients. Multivariate Cox regression model showed ETE, vascular invasion and CLNM were independent risk predictors of recurrence (P < 0.05).

CONCLUSION

Our study suggested that routine pCND should be performed for cN0 PTMC patients with score ≥ 3 according to the risk-scoring model. Moreover, patients with risk factors of recurrence should consider more complete treatment and more frequent follow-up.

Influence of Tumor Number on Clinicopathologic Features and Outcomes of Patients With Papillary Thyroid Carcinoma

OBJECTIVES

The purpose of this study was to investigate the significance of tumor number on clinicopathologic factors and outcomes of patients with papillary thyroid carcinoma (PTC).

METHODS

We retrospectively analyzed 667 patients with PTC. We compared clinicopathologic features of patients with a different tumor number. Cox proportional hazards model was used to analyze risk factors of recurrence.

RESULTS

In papillary thyroid microcarcinoma (PTMC), the increase in the number of tumor foci was related to a higher risk of minimal extrathyroidal extension (ETE) and lymphovascular invasion (P < .05). Patients with PTMC with four or more foci had a significantly higher risk of central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) than patients with solitary tumors (P < .05). Patients with macro-PTC with four or more foci and with three foci had a higher risk of gross ETE and lymphovascular invasion than patients with solitary tumors (P < .05). The increase in the tumor number was related to a higher risk of CLNM in macro-PTC (P < .05). The number of foci was the independent predictor of recurrence in patients with macro-PTC (P < .05).

CONCLUSIONS

An increase in the number of tumors was associated with an increased risk of aggressive clinicopathologic features in PTMC and macro-PTC. The number of tumor foci could influence risk of recurrence in macro-PTC.

The clonal origin of multifocal papillary thyroid cancer: intrathyroidal spread or independent tumors?

Multifocality is a common finding in papillary thyroid cancer but the molecular pathogenesis, prognosis and management of multifocal papillary thyroid cancer are debated. The clonal origin of multifocal papillary thyroid cancer represents a controversial aspect, as two opposite viewpoints have been proposed: independent origin or intraglandular spread. Different approaches have been used for inferring the clonality of multifocal papillary thyroid cancer, including X-chromosome inactivation, mutational analysis, determination of loss of heterozygosity and, more recently, next-generation sequencing. Next-generation sequencing, able to provide information on genetic heterogeneity and phylogenetic evolution in multifocal tumors, represents the most reliable approach. While most evidences indicated an independent origin of multifocal papillary thyroid cancer, a minority of studies suggested that multifocal papillary thyroid tumors might be monoclonally derived. This discrepancy may reflect technical limitations; nevertheless, studies based on next-generation sequencing indicated that both independent and clonal origins are possible. The co-existence of multiple tumors implies a high degree of genetic heterogeneity, which may influence the best and targeted therapeutic strategy. On the other hand, intrathyroidal dissemination may indicate metastatic potential of the dominant tumor, thereby prompting more aggressive treatments. In conclusion, data available in the literature indicated that multifocal papillary thyroid cancer may derived from both intraglandular spread and independent tumor foci. The understanding of the clonal origin of multifocal papillary thyroid tumors might represent an important issue in patient treatment.

Prevalence of BRAFV600E mutation in Asian series of papillary thyroid carcinoma-a contemporary systematic review

Papillary thyroid carcinoma (PTC), the most common malignancy of the endocrine system, is frequently driven by BRAFV600E mutation, which was reported in 35-60% cases in Western series. Numerous studies have recently emerged from Asian countries and regions; however sufficient summary is lacking to date. BRAF mutation serves as a diagnostic and prognostic tool in thyroid cancer, therefore establishing a rate of BRAF on the national scale could be of practical significance. We performed systematic reviews of available literature to investigate the prevalence of BRAF mutation in series of PTC from various Asian countries and regions. Out of the total 3,966 reports identified via initial screening, 138 studies encompassing over 40,000 PTCs were included for the final analysis. A vast majority (90.2%) of PTCs with known BRAF status were from East Asia, including China, South Korea, and Japan, with BRAF mutation rates of 71.2%, 75.5%, and 70.6%, respectively. Less abundant Indian and Saudi Arabian series found 45.6% and 46.3% prevalence of BRAFV600E in PTC, respectively. Much limited evidence was available from Thailand, Iran, Kazakhstan, Taiwan, Singapore, Indonesia, Hong Kong, Philippines, Vietnam, Iraq, and Myanmar. No relevant publications were found from other highly populated countries, such as Pakistan, Bangladesh, and Malaysia. After grouping by geographic region, we found that the highest rate of BRAFV600E was reported in the PTC series from East Asia (76.4%). Much lower rate (45-48%) was seen in PTC cohorts from South Asia, Central Asia, and the Middle East while the Southeast Asian series were in between (57%). Further subgroup analysis revealed that studies employing fresh frozen tissue and fine-needle aspirates showed higher rates of BRAF compared to those used formalin-fixed paraffin-embedded tissues. We found that the PTC series enrolled patients' cohorts after 2010 demonstrated a higher rate of BRAF compared to the earlier series. Finally, pediatric PTCs had lower BRAF prevalence compared to the baseline rate for the country. In conclusion, despite considerable among and within countries heterogeneity, the Asian PTC series showed a higher prevalence of BRAFV600E mutation than that in Western series. Causes of geographic heterogeneity, whether genuine (etiology, genetics) or methodology-related should be further investigated.

Significance of multifocality in papillary thyroid carcinoma

BACKGROUND

Although multifocality is often observed in papillary thyroid carcinoma (PTC), the associations with clinicopathologic factors and the prognostic value are still controversial. We aimed to identify the risk factors for multifocality and bilaterality, and investigate the significance of multifocality on prognosis in all PTC, papillary thyroid microcarcinoma (PTMC) and non-PTMC.

METHODS

Data from 635 patients who underwent lobectomy/total thyroidectomy plus cervical lymph node dissection for PTC were retrospectively analyzed. Clinicopathological factors associated with multifocal PTC and bilateral PTC were investigated by univariate analysis. Multivariate Cox regression analyses was used to identify the clinicopathological prognostic factors for recurrence-free survival.

RESULTS

Multifocal and bilateral PTC were observed in 157 (24.7%) and 99 (15.6%) patients, respectively. The frequency of large diameter (>1.0 cm), extrathyroidal extension (ETE), vascular invasion and central lymph node metastases (CLNM) was higher in multifocal PTC than that of solitary PTC. Moreover, ETE, vascular invasion, CLNM and lateral lymph node metastasis (LLNM) were more frequent in patients with 3 or more tumor foci compared to those with 2 tumor foci and 1 tumor lesion. Bilateral PTC had higher rates of ETE and CLNM. Multifocality was found to be the predictor of recurrence in all PTC, PTMC, and non-PTMC. In addition, the risk of recurrence increased with increasing number of tumor foci in all multifocal PTC patients and multifocal non-PTMC patients.

CONCLUSION

Although multifocality and bilaterality had more aggressive features in PTC, only multifocality was associated with the increased risk of recurrence. An increase in the number of tumors was associated with an increased risk of ETE, vascular invasion, CLNM and LLNM. The prognostic value of multifocality is particularly significant in non-PTMC patients.

A Comparison of Two Operation Methods Revealed the Risk Factors and the Necessity of LN-prRLN Dissection in Papillary Thyroid Carcinoma: A Retrospective Cohort Study in FUSCC

BACKGROUND

Although the American Thyroid Association (ATA) guidelines indicate that central lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) should be routinely dissected, pr-RLN dissection is often neglected due to the high risk of injury to the recurrent laryngeal nerve (RLN). The purpose of this study was to investigate the risk factors associated with LN-prRLN metastasis in patients with papillary thyroid carcinoma (PTC) by preoperative examination and the indications for LN-prRLN dissection.

METHODS

A total of 1487 consecutive patients with PTC who underwent total thyroidectomy or right lobectomy plus isthmic resection with central LN dissection (CLND) were divided into two groups: patients with LN-prRLN dissection (group A) and patients without LN-prRLN dissection (group B). Clinicopathologic data were reviewed of the patients who were operated on by the same thyroid surgery team in the Department of Head Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC) between August 2011 and May 2019. The relationships of LN-prRLN metastasis with clinicopathologic characteristics were analyzed by univariate and multivariate logistic regression.

RESULTS

The incidence of LN-prRLN metastasis was 34.1% (129/378). Univariate analysis showed that sex (P ≤ 0.001), tumor size (P ≤ 0.001), extrathyroidal extension (P=0.002), concurrent Hashimoto's thyroiditis (P=0.009), cLNMa (central lymph nodes anterior to the right recurrent laryngeal nerve) (P ≤ 0.001), cLNMa number (P ≤ 0.001), and lateral LN metastasis (LLNM) (P ≤ 0.001) were significantly associated with LN-prRLN metastasis in PTC. Multivariate logistic regression analysis revealed that tumor size (P=0.039), cLNMa (P=0.001), and LLNM (P=0.025) were independent risk factors for LN-prRLN metastasis in patients with PTC. Although there was no significant difference between the two groups in recurrence, we found that 4 cases relapsed in the LN-prRLN compartment in group B, while none relapsed in group A.

CONCLUSION

LN-prRLN metastasis is often identified in patients with PTC. Patients with large tumor sizes, cLNMa and LLNM are at a high risk of LN-prRLN metastasis and should be recommended for careful LN-prRLN dissection.

Predicting factors for central or lateral lymph node metastasis in conventional papillary thyroid microcarcinoma

BACKGROUND

Optimal management for papillary thyroid microcarcinoma (PTMC) remains controversial. The purpose of this study was to explore risk factors predictive of cervical lymph node metastasis in conventional PTMCs.

METHODS

Conventional PTMC patients (n = 2,404) undergoing surgery between 2010 and 2017 were grouped and analyzed according to the positivity of cervical lymph node.

RESULTS

Central lymph node (CLN) metastases and lateral lymph node (LLN) metastases were observed in 915 (38.1%) and 184 (7.7%) cases, respectively. Multivariate analysis found that male (odds ratio [OR] = 1.974, p < 0.001), younger age (OR = 1.601, p < 0.001), tumor size (OR = 1.935, p < 0.001), extrathyroidal extension (ETE) (OR = 1.647, p < 0.001), multifocality (OR = 1.416, p < 0.001), and intrathyroidal spreading (OR = 3.355, p < 0.001) predicted increased CLN metastasis. In particular, younger age, multifocality, and intrathyroidal spreading were significantly associated with a high number of CLN metastases (n ≥ 5). The presence of CLN metastasis was strongly associated with LLN metastasis (OR = 5.426, p < 0.001).

CONCLUSION

Male, younger age, tumor size, ETE, multifocality, and intrathyroidal spreading predict increased CLN metastasis in PTMCs. In patients with suspicious lateral lymphadenopathy, the presence of CLN metastasis is independently associated with LLN metastasis.

The potential role of carbon nanoparticles-assisted biopsy for sentinel lymph nodes of incidental thyroid carcinoma

Background

Some thyroid cancers are found after thyroidectomy for benign lesions, implying additional surgery and treatments. This work aimed to investigate the role of intraoperative sentinel lymph node biopsy (SLNB) for diagnosis of incidental thyroid carcinoma.

Methods

This was a retrospective study of 541 consecutive patients who underwent thyroid surgery between 02/2012 and 02/2014 at the Hunan Provincial People's Hospital. All patients were diagnosed with thyroid benign lesions preoperatively and intraoperatively. Among them, 375 underwent successful intraoperative SLNB using carbon nanoparticles (CNs).

Results

The preoperative diagnoses were nodular goiter (n=472), Hashimoto's disease with nodules (n=24), hyperthyroidism with nodules (n=16), and thyroid cysts with obstructive symptoms (n=29). In the SLNB group, SLN metastasis of thyroid microcarcinoma was confirmed in 21/392 cases (5.4%). These 21 patients received radical surgical treatment for thyroid carcinoma during the initial operation. In the no-SLNB group (n=149), seven patients (4.7%) were finally diagnosed with thyroid microcarcinoma. Six patients had to undergo a second surgery.

Conclusions

Intraoperative SLNB could help diagnose differentiated thyroid microcarcinoma that may be missed preoperatively and intraoperatively. This could prevent the need for a second surgery since the intraoperative frozen section examination of the SLNs can reveal metastasis from thyroid cancer.

Clonal analysis of early-stage bilateral papillary thyroid cancer identifies field cancerization

INTRODUCTION

Bilaterality is a newly identified indicator for aggressive tumor behavior and poor outcome in papillary thyroid cancer. However, the clonal origin of these bilateral tumors remains unclear.

METHODS

Here we analyzed 28 pairs of early-stage papillary thyroid cancers (stage I-II without extra-thyroidal extension, lymph node metastasis or distant metastasis) that underwent surgery at First Affiliated Hospital of Zhejiang University School of Medicine (Hangzhou, China). Genomic DNA was extracted from paraffin-embedded tissues after microdissection and analyzed for BRAF mutation and X-chromosome inactivation.

RESULTS

A total of 16 patients (16/28, 57.1%) harbored different BRAF status in bilateral tumors. Fourteen patients were available for X-chromosome inactivation assay and 10 of them achieved informative results. Bilateral tumors from four cases had distinct patterns of X-chromosome inactivation. Combining the results of X-chromosome inactivation and BRAF analysis, we demonstrated that at least 64.3% (18/28) cases harbored discordant X-chromosome inactivation or BRAF status, indicating their independent clonal origin in bilateral tumors.

CONCLUSIONS

The present study confirms "field cancerization" in early-stage bilateral thyroid cancers, suggesting that these subtype papillary thyroid cancers should be treated as independent and localized tumors.

The occurrence of and predictive factors for multifocality and bilaterality in patients with papillary thyroid microcarcinoma

Thyroidectomy or hemithyroidectomy may be performed as treatment for papillary thyroid microcarcinoma (PTMC). However, in cases of bilateral PTMCs, only thyroidectomies should be recommended. Sometimes bilateral PTMC may be undetected in presurgical evaluations, so reoperation might be necessary after a partial thyroid resection. The aim of this study was to assess the occurrence of and predictive factors for the multifocality and bilaterality of PTMCs.We performed a retrospective review of 4716 consecutive patients with thyroid tumors. Of these patients, 434 (9.2%) had thyroid malignancies. All patients underwent thyroidectomies with central and/or lateral lymph node dissection between January 2008 and December 2017. PTMC was identified in 177 (3.75%) individuals.Solitary PTMC was observed in 114 (64.4%) patients, multifocal PTMC was seen in 48 (27.1%) patients, and bilateral PTMC was detected in 15 (8.5%) patients. The occurrence of solitary PTMC increased from 11.1% in 2008 to 61.9% in 2017. The occurrence of multifocal tumors significantly decreased from 77.8% in 2008 to 6.3% to 18.4% in 2013 to 2016 (P < .05). The occurrence of bilateral tumors, with respect to all PTMC cases, did not change during the 10-year period. We observed significantly higher rates of hypoechogenicity, more microcalcifications, more irregular margins, larger tumor sizes, and higher vascularity in the patients with multifocal and bilateral tumors than in the patients with solitary tumors (P < .0001 for all).The occurrence of bilateral PTMC is not very common. In patients with PTMC, thyroidectomy should be considered when microcalcifications, an irregular tumor shape, unclear margins, hypoechogenicity, high vascularity, and a large tumor size are observed. These clinicopathological features are prognostic factors for multifocal and bilateral PTMC.

Investigation of the clonal origin of multifocal papillary thyroid carcinoma according to the X-chromosome inactivation pattern

Patients with papillary thyroid carcinoma (PTC) usually have multiple tumors, or foci. It remains unclear if these foci originate from independent tumors or a single tumor mass. The present study included 89 female patients with bilateral PTC who had been treated with a total thyroidectomy. An X-chromosome inactivation assay was used to examine the clonal origin of the tumors according to the status of the X-linked human androgen receptor gene. Of the 89 patients, 5 were informative. The X-chromosome inactivation pattern was the same in multiple foci in 3 cases, indicating a monoclonal origin of the tumors. In 1 case, the X chromosome inactivation pattern was different between the tumors. Mixed patterns were observed in 1 case. The results of the present study suggest that in certain cases of multifocal PTC, tumors arise independently, whereas in other cases, separate foci are the outcome of intra-thyroid spread by a single tumor mass.

A thyroid gland with over 30 foci of papillary thyroid carcinoma with activating BRAF V600E mutation

Multifocal papillary thyroid carcinoma (PTC) is common and the number of tumor foci rarely exceeds ten. The mechanism of multifocal disease is debated, with the two main hypotheses consisting of either intrathyroidal metastatic spread from a single tumor or independent multicentric tumorigenesis from distinct progenitor cells. We report the case of a 46-year-old woman who underwent total thyroidectomy and left central neck lymph node dissection after fine-needle aspiration of bilateral thyroid nodules that yielded cytological findings consistent with PTC. Final pathology of the surgical specimen showed an isthmic dominant 1.5 cm classical PTC and over 30 foci of microcarcinoma, which displayed decreasing density with increasing distance from the central lesion. Furthermore, all malignant tumors and lymph nodes harbored the activating BRAF V600E mutation. The present case highlights various pathological features that support a mechanism of intraglandular spread, namely a strategic isthmic location of the primary tumor, radial pattern of distribution and extensive number of small malignant foci and BRAF mutational homogeneity. Learning points: Multifocal papillary thyroid carcinoma (PTC) is commonly seen in clinical practice, but the number of malignant foci is usually limited to ten or less. There is no clear consensus in the literature as to whether multifocal PTC arises from a single or multiple distinct tumor progenitor cells. Strategic location of the dominant tumor in the thyroid isthmus may favor intraglandular dissemination of malignant cells by means of the extensive lymphatic network. An important pathological finding that may be suggestive of intrathyroidal metastatic spread is a central pattern of distribution with a reduction in the density of satellite lesions with increasing distance from the dominant focus. PTCs originating from the isthmus with intraglandular metastatic dissemination behave more aggressively. As such, a more aggressive treatment course may be warranted, particularly with regard to the extent of surgery.

Risk factors for cervical lymph node metastasis in papillary thyroid microcarcinoma: a study of 1,587 patients

Objective

The purposes of this study were to identify risk factors for cervical lymph node metastasis and to examine the association between BRAF^V600E status and clinical features in papillary thyroid microcarcinoma (PTMC).

Methods

A total of 1,587 patients with PTMC, treated in Tianjin Medical University Cancer Institute and Hospital from January 2011 to March 2013, underwent retrospective analysis. We reviewed and analyzed factors including clinical results, pathology records, ultrasound results, and BRAF^V600E status.

Results

Multivariate logistic regression analyses demonstrated that gender (male) [odds ratio (OR) = 1.845, P = 0.000], age (< 45 years)(OR = 1.606,P = 0.000), tumor size (> 6 mm) (OR = 2.137,P = 0.000), bilateralism (OR = 2.011, P = 0.000) and extrathyroidal extension (OR = 1.555, P = 0.001) served as independent predictors of central lymph node metastasis (CLNM). Moreover, CLNM (OR = 29.354, P = 0.000) served as an independent predictor of lateral lymph node metastasis (LLNM). Among patients with a solitary primary tumor, those with tumor location in the lower third of the thyroid lobe or the isthmus were more likely to experience CLNM (P < 0.05). Univariate analyses indicated that CLNM, LLNM, extrathyroidal extension, and multifocality were not significantly associated with BRAF^V600E mutation.

Conclusions

The present study suggested that prophylactic neck dissection of the central compartment should be considered in patients with PTMC, particularly in men with tumor size greater than 6 mm, age less than 45 years, extrathyroidal extension, and tumor bilaterality. Among patients with PTMC, BRAF^V600E mutation is not significantly associated with prognostic factors. For a better understanding of surgical management of PTMC and the risk factors, we recommend multicenter research and long-term follow-up.

Clinicopathologic risk factors for right paraesophageal lymph node metastasis in patients with papillary thyroid carcinoma

OBJECTIVES

To investigate risk factors associated with right paraesophageal lymph node (RPELN) metastasis in patients with papillary thyroid carcinoma (PTC) and to determine the indications for right lymph node dissection.

METHODS

Clinicopathologic data from 829 patients (104 men and 725 women) with PTC, operated on by the same thyroid surgery team at the First Affiliated Hospital of Harbin Medical University from January 2013 to May 2017, were analyzed. Overall, 309 patients underwent total thyroidectomy with bilateral lymph node dissection, 488 underwent right thyroid lobe and isthmic resection with right central compartment lymph node dissection, and 32 underwent near-total thyroidectomy (ipsilateral thyroid lobectomy with contralateral near-total lobectomy) with bilateral lymph node dissection.

RESULTS

The overall rate of central compartment lymph node metastasis was 43.5% (361/829), with right central compartment lymph node and RPELN metastasis rates of 35.5% (294/829) and 19.1% (158/829), respectively. Tumor size, number, invasion, and location, lymph node metastasis, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis were associated with RPELN in the univariate analysis, whereas age and sex were not. Multivariate analysis identified tumors with a diameter ≥ 1 cm, multiple tumors, tumors located in the right lobe, right central compartment lymph node metastasis, and right lateral compartment lymph node metastasis as independent risk factors for RPELN metastasis.

CONCLUSIONS

Lymph node dissection, including RPELN dissection, should be performed for patients with PTC with a tumor diameter ≥ 1 cm, multiple tumors, right-lobe tumors, right central compartment lymph node metastasis, or suspected lateral compartment lymph node metastasis.

Thyroid cancers of follicular origin in a genomic light: in-depth overview of common and unique molecular marker candidates

In recent years, thyroid malignances have become more prevalent, especially among women. The most common sporadic types of thyroid tumors of follicular origin include papillary, follicular and anaplastic thyroid carcinomas. Although modern diagnosis methods enable the identification of tumors of small diameter, tumor subtype differentiation, which is imperative for the correct choice of treatment, is still troublesome. This review discusses the recent advances in the field of molecular marker identification via next-generation sequencing and microarrays. The potential use of these biomarkers to distinguish among the most commonly occurring sporadic thyroid cancers is presented and compared. Geographical heterogeneity might be a differentiator, although not necessarily a limiting factor, in biomarker selection. The available data advocate for a subset of mutations common for the three subtypes as well as mutations that are unique for a particular tumor subtype. Tumor heterogeneity, a known issue occurring within solid malignancies, is also discussed where applicable. Public databases with datasets derived from high-throughput experiments are a valuable source of information that aid biomarker research in general, including the identification of molecular hallmarks of thyroid cancer.

Mutational Profile of Papillary Thyroid Carcinoma in an Endemic Goiter Region of North India

INTRODUCTION

Mitogen activated protein kinase (MAPK) pathway is regularly altered in papillary thyroid carcinomas (PTCs). Serine/threonine-protein kinase B-Raf (BRAF) V600E mutations were observed very frequently in PTC along with less frequent rat sarcoma (RAS) and rearranged during transfection (RET) gene, also known as RET/PTC translocation. The present study aimed to analyze the mutational profile of PTCs from an endemic Goiter area of North India.

METHODOLOGY

Tissues from 109 PTC patients were used to isolate DNA and RNA. BRAF V600E was detected by restriction fragment length polymorphism-polymerase chain reaction (PCR). RAS mutations were screened by using Sanger's sequencing method. RET/PTC rearrangements were analyzed by real-time PCR.

RESULTS

BRAF V600E mutation was detected in 51.38% (56/109) of PTCs, whereas RAS mutations were less frequent. No RET/PTC rearrangements were observed. BRAF V600E was found to be associated with the aggressive clinicopathological features such as lymph node metastasis, distant metastasis, higher tumor-node-metastasis stages, and high-risk groups.

CONCLUSION

The prevalence of BRAF V600E is high in patients from Indian Subcontinent and found to be associated with aggressive features of PTC. Concomitant mutations of BRAF V600E and RAS mutations impart more aggressiveness to PTCs.

SONOGRAPHIC FEATURES OF MULTIFOCAL PAPILLARY THYROID CARCINOMAS

OBJECTIVE

It is uncertain whether papillary thyroid carcinomas (PTCs) of the same subtype display similar sonographic features. This retrospective analysis of pre-operative sonographic and pathologic findings aimed to assess whether PTCs of the same subtype share sonographic features.

METHODS

Before undergoing thyroid surgery, 137 patients underwent ultrasound (US) examination. A single radiologist used a picture archiving and communication system and pathologic reports to investigate all sonographic features of the largest and second largest PTCs. Additionally, the radiologist evaluated the similarity of sonographic features between primary (largest), secondary (second largest), and daughter (secondary with same subtype as the primary) PTCs.

RESULTS

Of the 137 PTC patients, 48 (35.0%) had multiple PTCs; however, 5 had no US images of the secondary PTC. Of the 43 secondary PTCs with US images, 9 (20.9%) secondary PTCs were of a different subtype than the primary PTC and revealed sonographic features that differed from those of the primary PTC. Of the 48 patients with multiple PTCs, the subtype was the same in the primary and secondary PTCs in 34 (70.8%) patients. Of the 34 daughter PTCs, 32 (94.1%) had sonographic features similar to those of the primary PTC, whereas 2 (5.9%) showed different sonographic features than the primary PTC. There was no significant difference between primary and daughter PTCs in the size, location, sonographic features, or Korean Thyroid Imaging Reporting and Data System category ( P>.05).

CONCLUSION

Daughter PTCs show similar sonographic features as the primary PTC.

ABBREVIATIONS

K-TIRADS = Korean Thyroid Imaging Reporting and Data System; PTC = papillary thyroid carcinoma; US = ultrasound.

Molecular Profiling of Follicular Variant of Papillary Thyroid Cancer Reveals Low-Risk Noninvasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features: A Paradigm Shift to Reduce Aggressive Treatment of Indolent Tumors

INTRODUCTION

Encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) has been reclassified into noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) and invasive EFVPTC. NIFTP is considered a low-risk neoplasm. Therefore, follicular variant of papillary thyroid cancer (FVPTC) presently has two distinct histopathological subtypes - invasive EFVPTC and infiltrative/diffuse FVPTC. Molecular characteristics of these groups remain unclear.

METHODOLOGY

Thirty FVPTCs (10 NIFTPs, 12 invasive EFVPTCs, and 8 infiltrative/diffuse variants) were reviewed and screened for BRAF and RAS mutations by restriction fragment length morphism-polymerase chain reaction (PCR) and Sanger sequencing. The mRNA expression levels of iodine-metabolizing genes were analyzed using real-time PCR. The mutations status and mRNA expression levels were correlated with clinicopathological features.

RESULTS

All 10 NIFTPs had predominant follicular pattern. One case showed NRAS mutation, whereas none showed BRAF mutation. All invasive EFVPTC had capsular and/or lymphovascular invasion and 4/12 showed lymph node metastasis. BRAF and NRAS were seen in three cases each of invasive FVPTC. All eight infiltrating/diffuse FVPTCs showed infiltration into adjacent thyroid parenchyma and lymph node metastasis.

CONCLUSION

BRAF mutation was observed in 62.5% of cases; however, no NRAS mutation was found. Sodium iodide symporter (NIS) expressions in NIFTP were similar to that of normal thyroid tissue, whereas it was downregulated in invasive and infiltrative/diffuse FVPTC. Our study supports the argument that NIFTP can be considered as low-risk follicular thyroid neoplasm. Those tumors that harbor BRAF mutations may be offered a complete thyroidectomy because they show decreased expression of NIS gene which confers a tendency to lose radioactive iodine avidity and further recurrence of the tumor.

Heterogeneity of Thyroid Cancer

There are 5 main histological types of thyroid cancers (TCs): papillary, follicular (also known as differentiated), poorly differentiated, anaplastic (the most aggressive form), and medullary TC, and only the latter arises from thyroid C cells. These different forms of TCs show significant variability, both among and within tumours. This great variation is particularly notable among the first 4 types, which all originate from thyroid follicular cells. Importantly, this heterogeneity is not limited to histopathological diversity only but is also manifested as variation in several genetic and/or epigenetic alterations, the numbers of interactions between the tumour and surrounding microenvironment, and interpatient differences, for example. All these factors contribute to the great complexity in the development of a tumour from cancer cells. In the present review, we summarise the knowledge accumulated about the heterogeneity of TCs. Further research in this direction should help to gain a better understanding of the underlying mechanisms contributing to the development and diversity of TCs, paving the way toward more effective treatment strategies.

The synergic effect of BRAFV600E mutation and multifocality on central lymph node metastasis in unilateral papillary thyroid carcinoma

The purpose of this study is to evaluate the potential synergic effect of BRAF^V600E mutation and multifocality on central lymph nodes metastasis (CLNM) in the patients with unilateral papillary thyroid carcinoma (PTC). We enrolled 413 patients with unilateral PTCs who accepted prophylactic unilateral or bilateral central lymph node dissection (LND). Univariate and multivariate analyses were made to determine the association between related factors and CLNM. Then, all patients were divided into 4 groups based on their status of BRAF^V600E mutation and multifocality. Relative excess risk of interaction (RERI), attributable proportion (AP) of interaction and synergy index (SI) were applied to evaluate the interactive effect of these two factors on CLNM. Results showed that BRAF^V600E mutation and multifocality were independent risk factors for CLNM. A further study revealed that unilateral PTCs accompanying multifocality with BRAF^V600E mutation had the highest incidence of CLNM compared with other subgroups. Besides, RERI was 4.323 (95% CI = 1.276-7.369), AP was 0.523 (95% CI = 0.364-0.682) and SI was 2.469 (95% CI = 1.607 to 3.794), indicating a significant additive interaction of BRAF^V600E mutation and multifocality on CLNM. The present study has confirmed that BRAF^V600E mutation and multifocality are risk factors for CLNM in unilateral PTC. Additionally, unilateral PTC patients accompanying multifocality with BRAF^V600E mutation may have an increased risk of CLNM in clinically negative CLNM.

Internal Spreading of Papillary Thyroid Carcinoma: A Case Report and Systemic Review

An 18-year-old female diagnosed finally as PTC with intrathyroid spread was reported, and the diagnosis and surgical treatment of internal spreading of PTC were discussed. One lump was found on the thyroid isthmus by physical examination and B ultrasound, and multiple nodular shadows were found by CT. This patient finally underwent total thyroidectomy with bilateral central node dissection due to multifocal papillary thyroid carcinoma except PTC in the isthmus found in right lobe by intraoperative frozen section. The pathological section showed a major thyroid carcinoma in thyroid isthmus with scattered micropapillary carcinoma around it in the whole thyroid gland. The small lesions are distributed around central lesion in a radial form and the number of small lesions decreases with increased distance from central lesion. PTC with internal spread should be distinguished from multifocal PTC and poorly differentiated PTC in pathology. Thyroid cancerous node had a large diameter; it was likely to have internal spread. Combined imaging before surgery should be valued to diagnose PTC with internal spread. Preoperative CT and intraoperative frozen section are helpful for surgical volume selection of PTC with internal spread.

BRAFV600E Mutation: Has It a Role in Cervical Lymph Node Metastasis of Papillary Thyroid Cancer?

BACKGROUND

The BRAF^V600E mutation is common in papillary thyroid cancer (PTC). Lymph node metastasis (LNM) may be associated with poor prognosis. However, the LNM mechanism remains unclear.

OBJECTIVES

Our aim was to evaluate the prevalence of the BRAF^V600E mutation in primary tumors and accompanying LNM at the time of diagnosis.

METHODS

This retrospective study included 51 PTC patients (40 women, 11 men; mean age 40.0 ± 16.5 years; range 6-81) who underwent total thyroidectomy accompanied by a lateral neck dissection due to preoperatively detected LNM. Real-time PCR was used for the detection of the BRAF^V600E mutation in specimens from primary thyroid tumors and metastatic lymph node tumors.

RESULTS

The prevalence of the BRAF^V600E mutation was 64.7% (n = 33) in primary tumors and 47.1% (n = 24) in metastatic lymph nodes. Of 33 patients with BRAF^V600E-positive primary tumors, 18 (54.5%) had BRAF^V600E-positive metastatic lymph nodes. Of 18 patients with BRAF^V600E-negative primary tumors, 6 (33.3%) had BRAF^V600E-positive metastatic lymph nodes. The presence of the BRAF^V600E mutation in the primary tumor did not affect the tumor size, but the diameter of metastatic lymph nodes significantly increased (by nearly 3 mm) with the presence of BRAF^V600E in LNM (p = 0.01).

CONCLUSIONS

In our study, the BRAF^V600E mutation did not show a one-to-one correspondence. This indicates that the presence of BRAF^V600E in the primary tumor is not clonal and addresses the role of intratumor heterogeneity in PTC tumorigenesis. This supports the theses that mutations occur in the later stages of tumorigenesis, might be subclonal, and develop de novo, or that some other factors may be involved in the development of metastasis.

BRAF analysis before surgery for papillary thyroid carcinoma: correlation with clinicopathological features and prognosis in a single-institution prospective experience

Background:

Risk stratification in patients with papillary thyroid carcinoma (PTC) currently relies on postoperative parameters. Testing forBRAFmutations preoperatively may serve as a novel tool for identifying PTC patients at risk of persistence/recurrence after surgery.

Methods:

The study involved 185 consecutive patients with a histological diagnosis of PTC andBRAFanalysis performed on thyroid fine-needle aspiration biopsy (FNAB). We assessedBRAFstatus in FNAB specimens obtained before thyroidectomy for PTC, and examined its association with the clinicopathological characteristics identified postoperatively, and with outcome after a mean 55±15 months of follow-up.

Results:

One hundred and fifteen of 185 (62%) PTCs carried aBRAFmutation. Univariate analysis showed thatBRAFstatus correlated with the histological variant of PTC, cancer size, and stage at diagnosis, but not with gender, age, multifocality, or lymph node involvement.BRAF-mutated cases had a higher prevalence of persistent/recurrent disease by the end of the follow-up (11% vs. 8%), but this difference was not statistically significant. The Kaplan-Meier curve shows that among the patients with persistent/recurrent disease,BRAF-mutated patients needed a second treatment earlier than patients withBRAFwild-type, although the difference did not completely reach the statistical significance.

Conclusions:

Our study confirmed that preoperatively-identifiedBRAFmutation are associated with certain pathological features of PTC that correlate with prognosis. We speculate that it has a role in identifying PTCs that would generally be considered low-risk but that may reveal an aggressive behavior during their follow-up.

Relevance of BRAF and NRAS mutations in the primary tumor and metastases of papillary thyroid carcinomas

BACKGROUND

Multifocality of papillary thyroid carcinoma (PTC) is common. BRAF and NRAS mutations are the most frequent genetic alterations in PTC. The purpose of this study was to determine the distribution and relevance of BRAF^T1799A and NRAS mutations in PTC.

METHODS

BRAF^T1799A and NRAS mutations were evaluated in 195 intrathyroid or metastatic foci from 29 patients with multifocal PTC.

RESULTS

BRAF^T1799A mutation was positive in 46.7% of the 59 intrathyroid and 136 metastatic foci (91/195 foci). Heterogeneous BRAF pattern was observed in 51.7% patients (15/29 patients). Irrespective of BRAF status at diagnosis (thyroid or nodes), all patients with recurrent PTC presented BRAF-mutated metastases during follow-up. All foci were negative for NRAS mutations.

CONCLUSION

BRAF but not NRAS mutations were heterogeneously distributed among primary tumor, nodal sites, and recurrent disease. The BRAF status of metastases generated during the follow-up can differ from the status of foci at diagnosis. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1772-1779, 2016.

Clonality analysis of multifocal papillary thyroid carcinoma by using genetic profiles

Papillary thyroid carcinoma (PTC) is the most common adult thyroid malignancy and often presents with multiple anatomically distinct foci within the thyroid, known as multifocal papillary thyroid carcinoma (MPTC). The widespread application of the next-generation sequencing technologies in cancer genomics research provides novel insights into determining the clonal relationship between multiple tumours within the same thyroid gland. For eight MPTC patients, we performed whole-exome sequencing and targeted region sequencing to identify the non-synonymous point mutations and gene rearrangements of distinct and spatially separated tumour foci. Among these eight MPTCs, completely discordant mutational spectra were observed in the distinct cancerous nodules of patients MPTC1 and 5, suggesting that these nodules originated from independent precursors. In another three cases (MPTC2, 6, and 8), the distinct MPTC foci of these patients had no other shared mutations except BRAF V600E, also indicating likely independent origins. Two patients (MPTC3 and 4) shared almost identical mutational spectra amongst their separate tumour nodules, suggesting a common clonal origin. MPTC patient 7 had seven cancer foci, of which two foci shared 66.7% of mutations, while the remaining cancer foci displayed no common non-synonymous mutations, indicating that MPTC7 has multiple independent origins accompanied by intraglandular disease dissemination. In this study, we found that 75% of MPTC cases arose as independent tumours, which supports the field cancerization hypothesis describing multiple malignant lesions. MPTC may also arise from intrathyroidal metastases from a single malignant clone, as well as multiple independent origins accompanied by intrathyroidal metastasis.

Bilaterality weighs more than unilateral multifocality in predicting prognosis in papillary thyroid cancer

Papillary thyroid cancer (PTC) often presents as multifocal tumor;, however, whether multifocality is associated with poor prognosis remains controversial. The aims of this retrospective study were to identify the characteristics of PTC with multifocal tumors and evaluate the association between the location and prognosis. We reviewed the medical records of 496 patients who underwent total thyroidectomy for PTC. Patients were classified as three groups: N1 (solitary tumor), N2 (2 or more foci within unilateral lobe of thyroid), and N3 (bilateral tumors, at least one tumor focus for each lobe of thyroid). We analyzed the differences of clinicopathologic features and clinical outcomes among the three groups. Cox regression model was used to assess the relation between the different locations of multifocal tumors and prognosis. Although the differences of clinicopathologic features such as the size of tumor, extrathyroidal extension, and cervical lymph node metastasis were not significant among the three groups, the bilateral-multifocality was proved to be an independent risk factor for neck recurrence (hazard ratio (HR) = 4.052, 95 % confidence interval (CI) 2.070-7.933), distant metastasis (HR = 3.860, 95 % CI 1.507-9.884), and cancer death (HR = 7.252, 95 % 2.189-24.025). In addition, extrathyroidal extension (HR = 2.291, 95 % CI 1.185-4.427) and older age >45 years (HR = 6.721, 95 % CI 2.300-19.637) were also significant predictors for neck recurrence and cancer death, respectively. Therefore, bilateral-multifocality as an indicator for more extensive tumor location could be used to assess the risk of recurrence and mortality in PTC. Given the poor prognosis associated with bilateral-multifocality and other risk factors, aggressive therapy and intensive follow-up were recommended for PTC patients with them.

Predictors of incomplete response to therapy among Filipino patients with papillary thyroid cancer in a tertiary hospital

BACKGROUND

Although survival rate in papillary thyroid cancer (PTC) is high, the risk of persistence and recurrence together with the dramatic rise in its incidence cannot be overemphasized. Filipinos are considered to be at greater risk for negative outcomes. A paradigm shift in the management of PTC introduces re-stratification based on response to therapy which was reported to have better correlation with long-term outcome. The study aimed to identify predictors of incomplete response after thyroidectomy and radioiodine therapy among patients with PTC. The results of the study may have important implications in our understanding of the disease process allowing more aggressive treatment and monitoring of certain subgroups of patients.

METHODOLOGY

Retrospective review of 225 patients with PTC (59% ATA low risk, 30 % ATA intermediate risk and 11% ATA high risk) who underwent thyroidectomy and radioiodine therapy was performed. Thirteen variables were considered (age, gender, histopathological variant, stage, extent of disease, MACIS score, AMES score, primary tumour size, lymph node, lymphovascular invasion, bilaterality, multifocality and preoperative TSH level). Logistic regression analysis using Backward Wald algorithm was used to identify independent predictors of incomplete response to therapy after 24 months.

RESULTS

Of the 225 patients, 69 (31%) had incomplete response. Biochemical and structural (predominantly thyroid bed, lung and bone) incomplete response was observed in 6 and 63 patients, respectively. Incomplete response was documented in 8, 54 and 92% of low-, intermediate- and high-risk patients based on ATA recommendation. Incomplete response was significantly dependent on gender, lymph node involvement and location, extent of malignancy and multifocality taking into account the size of concurrent tumours (p < 0.05). The model was found to have high sensitivity (71%) and specificity (96%).

CONCLUSION

A significant fraction of PTC patients experienced incomplete response to therapy. Our data suggest that male gender, lateral or mediastinal lymph node involvement, class III extent of disease by De Groot and multifocality with concurrent tumour or tumours more than 1 cm are major predictors of incomplete response. Not all predictors of recurrence and mortality are consistent predictors of treatment response which may be equally important in a disease with low mortality but significant morbidity like PTC.

The BRAFT1799A mutation is not associated with occult contralateral carcinoma in patients with unilateral papillary thyroid microcarcinoma

BACKGROUND

The phenomenon of occult carcinoma maybe observed in patients with clinically unilateral papillary thyroid microcarcinoma (PTMC). Although many studies have reported that the BRAFT1799A mutation is associated with aggressive PTMC, the relationship between BRAFT1799A mutation and occult carcinoma is unclear. The aim of this study was to investigate the risk factors, including BRAFT1799A mutation, for occult contralateral carcinoma in clinically unilateral PTMC accompanied by benign nodules in the contralateral lobe.

MATERIALS AND METHODS

From January 2011 to December 2013,we prospectively enrolled 89 consecutive PTMC patients with clinically unilateral carcinoma accompanied by benign nodules in the contralateral lobe who received a total thyroidectomy and cervical lymph node dissection. BRAFT1799A mutation was tested by pyrosequencing on postoperative paraffin specimens. The frequency and predictive factors for occult contralateral carcinoma were analyzed with respect to the following variables: age, gender, family history, tumor size, presence of Hashimoto thyroiditis, extrathyroidal extension, central lymph node metastasis, multifocality of primary tumor, or BRAFT1799A mutation.

RESULTS

A total of 36 patients (40.4%) had occult PTMC in the contralateral lobe. The median diameter of the occult tumors was 0.33±0.21 cm. The BRAFT1799A mutation was found in 38 cases (42.7%). According to the univariate analysis, there were no significant differences between the presence of occult contralateral carcinoma and age, gender, family history, tumor size, presence of Hashimoto thyroiditis, extrathyroidal extension, central lymph node metastasis, multifocality of primary tumor, or BRAFT1799A mutation.

CONCLUSIONS

Using current methods, it is difficult to preoperatively identify patients with PTMC, and further research is needed to determine predictive factors for the presence of occult contralateral carcinoma in patients with unilateral PTMC.

BRAF Testing in Multifocal Papillary Thyroid Carcinoma

BACKGROUND

BRAF V600E mutation is associated with poor prognosis in patients with papillary thyroid carcinoma (PTC). PTC is often multifocal, and there are no guidelines on how many tumors to test for BRAF mutation in multifocal PTC.

METHODS

Fifty-seven separate formalin-fixed and paraffin-embedded PTCs from twenty-seven patients were manually macrodissected and tested for BRAF mutation using a commercial allele-specific real-time polymerase chain reaction-based assay (Entrogen, Woodland Hills, CA). Data related to histologic characteristics, patient demographics, and clinical outcomes were collected.

RESULTS

All mutations detected were BRAF V600E. Seventeen patients (63%) had concordant mutation status in the largest and second-largest tumors (i.e., both were positive or both were negative). The remaining ten patients (37%) had discordant mutation status. Six of the patients with discordant tumors (22% overall) had a BRAF-negative largest tumor and a BRAF-positive second-largest tumor. No histologic feature was found to help predict which cases would be discordant.

CONCLUSIONS

Patients with multifocal PTC whose largest tumor is BRAF-negative can have smaller tumors that are BRAF-positive. Therefore, molecular testing of more than just the dominant tumor should be considered. Future studies are warranted to establish whether finding a BRAF mutation in a smaller tumor has clinical significance.

Multifocal Papillary Thyroid Cancer Increases the Risk of Central Lymph Node Metastasis

BACKGROUND

Papillary thyroid cancer (PTC) is the most common thyroid malignancy, with a strong predilection for lymph node metastasis, most commonly to the central neck compartment (level VI). Few studies have evaluated lymph node metastasis in multifocal PTC, and the role of level VI dissection in the management of PTC remains controversial. This retrospective analysis evaluated the rate of level VI lymph node positivity in multifocal PTC, as compared with unifocal disease, in order to inform surgical decision making better.

METHODS

Patients with PTC who underwent total or hemi-thyroidectomy plus level VI lymph node dissection at the authors' institution between January 2008 and June 2014 were included (N=227). The number and laterality of PTC foci, lymphovascular invasion (LVI), extrathyroidal extension (ETE), and positive/total number of level VI lymph nodes were recorded. Fisher's exact test was used to determine univariate associations, and multivariate analysis was done by logistical regression.

RESULTS

There was an association between the number of PTC foci and level VI node positivity (p<0.001), with an odds ratio (OR) of 2.355 in patients with three or more tumor foci (p=0.026). The OR for central neck metastasis was 1.088 with each additional focus of PTC (p=0.018). The risk of level VI node positivity in the presence of one or two foci was only 19%, with no appreciable difference between one and two foci. This risk increased in the presence of between three and nine foci (38%), and 10 or more foci (88%). Level VI node positivity was associated with ETE (p<0.001), LVI (p<0.001), and size of the largest focus (p<0.001). There was no association between level VI lymph node positivity and male sex (p=0.089), bilaterality (p=0.276), or age (p=0.076).

CONCLUSIONS

There is a significant association between multifocal PTC and level VI lymph node positivity, increasing proportionally with the number of foci. These findings recognize multifocality as a sign of tumor aggressiveness, as evidenced by a higher propensity for lymph node metastasis.

Identification of occult tumors by whole-specimen mapping in solitary papillary thyroid carcinoma

We undertook this study to estimate an accurate incidence and spread patterns of occult papillary thyroid carcinoma (PTC) in patients with a preoperative diagnosis of solitary PTC by using whole-specimen mapping of all specimens after a total thyroidectomy. Enrolled prospectively in this whole-thyroid mapping study are 82 consecutive patients who underwent a total thyroidectomy under a preoperative diagnosis of solitary PTC. All thyroidectomy specimens were serially sectioned in 2 mm thickness and whole-thyroid mapping was carried out for additional foci of occult PTC. The frequencies of occult lesions detected in the whole and contralateral lobe were determined, and clinicopathologic factors associated with multifocality were assessed. Whole-thyroid mapping revealed 66 occult PTC lesions missed by preoperative ultrasound in 37 (45.1%) of the 82 patients. The great majority (92.5%) of the occult PTC was smaller than 3 mm in size and 25 patients (30.5%) had contralateral lesions. We found that the male sex was an independent predictor of multifocality (odds ratio (OR), 3.00; 95% CI, 1.11-8.14), adjusting for preoperative findings. Analysis with pathologic parameters showed that the male sex (OR, 5.03; 95% CI, 1.68-15.08) and extrathyroidal extensions (OR, 3.03; 95% CI, 1.03-8.95) were associated with multifocal PTC. However, none of the clinicopathologic factors evaluated predicted contralateral PTC. Our study demonstrates the diagnostic limitations of ultrasound for the detection of multifocal PTC and the need to consider the possibility of occult lesions in the management of solitary PTC, especially in male patients.

Multifocality and bilaterality of papillary thyroid microcarcinoma

Objectives

Papillary thyroid carcinomas frequently occur as two or more separate foci within the thyroid gland (18%-87%). However, those multifocal tumors are easy to be undetected by preoperative radiologic evaluations, which lead to remnant disease after initial surgery. We aimed to study the incidence of multifocal papillary thyroid microcarcinomas (PTMCs), diagnostic accuracy of preoperative radiologic evaluation, predictive factors, and the chance of bilateral tumors.

Methods

Two hundred and seventy-seven patients with PTMC were included in this study. All patients underwent total thyroidectomy as an initial treatment. Medical records, pathologic reports, and radiological reports were reviewed for analysis.

Results

Multifocal PTMCs were detected in 100 of 277 patients (36.1%). The mean number of tumors in each patient was 1.6±1.1, ranging from 1 to 10. The additional tumor foci were significantly smaller (0.32±0.18 cm) than the primary tumors (0.63±0.22 cm) (P<0.001). There was no significant relationship between primary tumor size and the presence of contralateral tumors. With more tumors detected in one lobe, there was greater chance of contralateral tumors; 18.8% with single tumor focus, 30.2% with 2 tumor foci, and 46.2% with 3 or more tumor foci in one lobe. Sensitivity of preoperative sonography was 42.7% for multifocal tumors and 49.0% for bilateral tumors. With multivariate analysis, nodular hyperplasia was the only significant factor for multifocal tumors.

Conclusion

In cases of PTMCs, the incidence of multifocal tumors is high. However, additional tumor foci are too small to be diagnosed preoperatively, especially under the recent guidelines on radiologic screening tests for papillary thyroid carcinoma. Multifocal PTMCs have high risk of bilateral tumors, necessitating more extensive surgery or more thorough follow-up.

High TPOAb Levels (>1300 IU/mL) Indicate Multifocal PTC in Hashimoto’s Thyroiditis Patients and Support Total Thyroidectomy

Objective

We aimed to identify whether thyroid peroxidase antibodies (TPOAb) are indicative of multifocal papillary thyroid cancer (PTC) in Hashimoto’s thyroiditis (HT) patients and may help to determine necessity for total thyroidectomy.

Study design

Retrospective cohort study.

Setting

Teaching hospital.

Subjects

A total of 808 consecutive patients with HT alone or with HT and unifocal or multifocal PTC were included.

Methods

Preoperative thyroid function tests, TPOAb determination, preoperative ultrasonography, intraoperative frozen biopsy, and postoperative routine pathologic examination to confirm thyroid nodules were performed for all patients. Patients with nodules or malignancy potential on ultrasound and fine-needle aspiration cytology were included. Patients with hyperthyroidism, concomitant chronic disease, a history of other malignant tumors, or history of major diseases were excluded. All patients underwent surgery, and HT and PTC were confirmed by postoperative pathologic results.

Results

No significant differences were found in age and sex between groups ( P > .05). TPOAb ≤1300 IU/mL were more prevalent in the HT + unifocal PTC group than in the other groups (99.57% vs 15.52% and 60.75%, P < .001). TPOAb >1300 IU/mL were more prevalent in the HT + multifocal PTC group than in the other groups (84.48% vs 0.43% and 39.25%; P < .001). Compared to the other groups, the HT + multifocal PTC group had higher percentages of patients with elevated thyroid-stimulating hormone and positive central lymph node (LN) metastasis (elevated thyroid-stimulating hormone: 8.7% vs 3.2% and 6.5%, P = .008; positive central LN metastasis: 74.57% vs 67.38% and 0%, P < .001).

Conclusion

High TPOAb levels (>1300 IU/mL) are definitive indicators of multifocal PTC in HT patients, which may support surgical treatment with total thyroidectomy.

Multicentric occurrence of multiple papillary thyroid carcinomas--HUMARA and BRAF mutation analysis

Papillary thyroid carcinomas (PTCs) occasionally form multiple tumor foci in different sites of the same thyroid gland. However, it is controversial whether discrete nodules of PTC arise independently (multicentric occurrence) or are seeded from a single tumor via lymphatic channels (intraglandular metastasis). In order to determine the clonal origin of multiple PTCs, we examined X-chromosome inactivation patterns using a human androgen receptor gene-based assay (HUMARA) and the BRAF mutation using allele-specific PCR (AS-PCR) in 32 microdissected cancerous tissues from 14 Japanese women with multifocal PTC. All tumor foci were greater than 3 mm in size and met the criteria for microscopic classical PTC. Samples from 13 of the 14 patients were informative based on HUMARA. Tumor foci from two cases (15.4%) displayed a discordant X-chromosome inactivation pattern. Foci from the other 11 cases (84.6%) showed a concordant inactivation pattern of the X-chromosome. AS-PCR indicated that BRAF mutational status between the tumor foci was discordant in three (25%) and concordant in nine (75%) of 12 available cases. When the results of these two molecular analyses were combined, 28.6% of the cases were discordant in X-chromosome inactivation pattern and/or BRAF mutation, suggesting multicentric origin. Some of the remaining concordant cases also may be of multicentric origin. These results support a hypothesis that multicentric occurrence in multiple PTCs may be common, possibly greater than 30%. Although the exact mechanism of multicentric occurrence is still unclear, our findings contribute to the understanding the histogenesis of papillary thyroid carcinoma.

Intratumor heterogeneity and clonal evolution in an aggressive papillary thyroid cancer and matched metastases

The contribution of intratumor heterogeneity to thyroid metastatic cancers is still unknown. The clonal relationships between the primary thyroid tumors and lymph nodes (LN) or distant metastases are also poorly understood. The objective of this study was to determine the phylogenetic relationships between matched primary thyroid tumors and metastases. We searched for non-synonymous single-nucleotide variants (nsSNVs), gene fusions, alternative transcripts, and loss of heterozygosity (LOH) by paired-end massively parallel sequencing of cDNA (RNA-Seq) in a patient diagnosed with an aggressive papillary thyroid cancer (PTC). Seven tumor samples from a stage IVc PTC patient were analyzed by RNA-Seq: two areas from the primary tumor, four areas from two LN metastases, and one area from a pleural metastasis (PLM). A large panel of other thyroid tumors was used for Sanger sequencing screening. We identified seven new nsSNVs. Some of these were early events clonally present in both the primary PTC and the three matched metastases. Other nsSNVs were private to the primary tumor, the LN metastases and/or the PLM. Three new gene fusions were identified. A novel cancer-specific KAZN alternative transcript was detected in this aggressive PTC and in dozens of additional thyroid tumors. The PLM harbored an exclusive whole-chromosome 19 LOH. We have presented the first, to our knowledge, deep sequencing study comparing the mutational spectra in a PTC and both LN and distant metastases. This study has yielded novel findings concerning intra-tumor heterogeneity, clonal evolution and metastases dissemination in thyroid cancer.

Total surface area is useful for differentiating between aggressive and favorable multifocal papillary thyroid carcinomas

PURPOSE

The purpose of the present study was to identify more useful parameters for predicting behaviors of multifocal papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

We investigated dominant tumor diameter (TD), total tumor diameter (TTD), and total surface area (TSA) in tumors from 588 patients and evaluated their usefulness as parameters for assessment of tumor behaviors in multifocal PTCs.

RESULTS

In 588 PTCs, tumor multifocality was found in 179 PTCs (30.4%). Multifocal tumors were significantly associated with extrathyroidal extension, lymph node metastasis, and higher tumor stage grouping (p<0.001, p<0.001, and p<0.001, respectively). The rates of nodal metastasis increased with greater TSA and TTD in PTCs. Multifocal papillary thyroid microcarcinomas (mPMCs) with TSA >3.14 cm² had higher rates of nodal metastasis than mPMCs with TSA ≤3.14 cm² (p=0.038); however, there was no significant difference between mPMCs with TTD >1.0 cm and with TTD ≤1.0 cm (p=0.325). In addition, nodal metastasis was more frequent in mPMCs with TSA >3.14 cm² than in unifocal papillary thyroid microcarcinomas (uPMCs) (TD ≤1.0 cm) (p=0.002), but not overt unifocal PTCs (TD >1.0 cm) (p=0.244).

CONCLUSION

Our results suggest that mPMCs with TSA >3.14 cm² show more aggressive behavior than uPMCs and mPMCs with TSA ≤3.14 cm². TSA could be useful in distinguishing aggressive mPMCs from favorable cases.

BRAF mutation is not predictive of long-term outcome in papillary thyroid carcinoma

The BRAF mutation occurs commonly in papillary thyroid carcinoma (PTC). Previous investigations of its utility to predict recurrence-free survival (RFS) and disease-specific survival (DSS) have reported conflicting results and its role remains unclear. The purpose of this retrospective study was to determine the incidence of the BRAF mutation and analyze its relationship to clinicopathologic risk factors and long-term outcomes in the largest, single-institution American cohort to date. BRAF mutational status was determined in 508 PTC patients using RFLP analysis. The relationships between BRAF mutation status, patient and tumor characteristics, RFS, and DSS were analyzed. The BRAF mutation was present in 67% of patients. On multivariate analysis, presence of the mutation predicted only for capsular invasion (HR, 1.7; 95% CI, 1.1–2.6), cervical lymph node involvement (HR, 1.7; 95% CI, 1.1–2.7), and classic papillary histology (HR, 1.8; 95% CI 1.1–2.9). There was no significant relationship between the BRAF mutation and RFS or DSS, an observation that was consistent across univariate, multivariate, and Kaplan–Meier analyses. This is the most extensive study to date in the United States to demonstrate that BRAF mutation is of no predictive value for recurrence or survival in PTC. We found correlations of BRAF status and several clinicopathologic characteristics of high-risk disease, but limited evidence that the mutation correlates with more extensive or aggressive disease. This analysis suggests that BRAF is minimally prognostic in PTC. However, prevalence of the BRAF mutation is 70% in the general population, providing the opportunity for targeted therapy.