Extrathyroidal extension predicts extranodal extension in patients with positive lymph nodes: an important association that may affect clinical management

The Effect of Hemithyroidectomy in Papillary Thyroid Carcinoma with an Exclusive Involvement of the Recurrent Laryngeal Nerve: A Retrospective Study with a Propensity Score-Matched Analysis

BACKGROUND

Involvement of the recurrent laryngeal nerve (RLN) in papillary thyroid carcinoma (PTC) is an important prognostic factor and is associated with a higher risk of recurrence. This study aimed to retrospectively analyze the outcomes of patients treated with hemithyroidectomy (HT) in PTC patients with an exclusive RLN invasion who could not tolerate staged surgery, did not wish to undergo another operation, or had other reasons.

METHODS

A retrospective review was conducted on 163 patients with PTC and exclusive RLN involvement at our institution between 2013 and 2019. Patients were divided into a total thyroidectomy (TT) group and HT group. The clinicopathologic factors and prognostic outcomes were compared between the two groups. A propensity score-matched analysis was carried out to reduce selection bias, with the following covariates: gender, age, tumor size, multifocality, central lymph node metastasis (CLNM), and RLN resection. The Kaplan-Meier method was used for a comparison of recurrence outcomes.

RESULTS

In the baseline data of the 163 PTC patients, tumor size (p < 0.001), multifocality (p = 0.011), CLNM (p < 0.001), and RLN resection (p < 0.008) in the TT and HT groups differed significantly, whereas age and gender did not differ between the two groups. The TT group reported significantly higher temporary and permanent hypoparathyroidism than the HT group (p < 0.001 and p = 0.042, respectively). With 72-month median follow-up, 11 (6.7%) patients developed recurrence. After propensity score matching, 24 patients with HT and 43 patients with TT were included. Recurrence-free survival (RFS) in the matched samples showed no difference between the TT and HT groups (p = 0.092).

CONCLUSION

Our results indicate that HT may be a feasible treatment for PTC patients with exclusive RLN involvement in specific circumstances without significantly increasing the risk of recurrence. Performing a thorough preoperative examination is crucial to exclude multifocal tumors and lymph node metastasis before undergoing HT.

Extrathyroidal extension or tumor size of primary lesion influences thyroid cancer outcomes

AIMS

Extrathyroidal extension (ETE) is a determined factor of T3 and T4 stage of differentiated thyroid cancer (DTC) in American Joint Committee on Cancer. We aimed to compare clinical outcomes between different extent of ETE according to tumor size.

METHODS

Patients diagnosed with DTC were collected from the Surveillance, Epidemiology, and End Results database from 2004 to 2015. They were categorized into two groups by presence of lymph node metastases (LNM) or distant metastases (DM): group A: no presence of LNM and DM, and group B: presence of LNM or DM. Each group was further divided into four groups according to tumor size: <1 cm, 1-2 cm, 2-4 cm, >4 cm. ETE was divided into three groups by the extent: no ETE, microscopic ETE, and macroscopic ETE. Kaplan-Meier method and log-rank test were used to analyze cancer-specific survival (CSS).

RESULTS

91,975 patients were included. In groups A and B, for tumor size 1 cm, there was no significant difference in CSS between no ETE and microscopic ETE, while a significant difference was observed between no ETE and macroscopic ETE. For tumor size >1 cm, there were significant differences in CSS (both no ETE vs. micro ETE and no ETE vs. macro ETE).

CONCLUSION

We suggests that when tumor size is more than 1 cm, micro ETE is significantly associated with poorer outcome. T3 and T4 stages may take account into tumor size rather than merely based on the presence and extent of ETE. It may be prudent to revisit the omission of micro ETE in TNM staging.

Risk factors for recurrent disease in small papillary thyroid cancers - a Swedish register-based study

AIMS

To study the correlation between clinicopathological risk factors and the risk for intervention-requiring cancer recurrence in patients with small papillary thyroid cancers (sPTCs).

MATERIALS AND METHODS

Records for 397 patients with sPTC (T1 ≤ 20mm) were obtained from the Scandinavian Quality Register for Thyroid, Parathyroid and Adrenal Surgery (SQRTPA) between 2010 and 2016. Follow-up time was at least 5 years. Data regarding intervention-requiring cancer recurrence were obtained from patient medical records and analysed regarding lymph node (LN) status (N0, N1a and N1b) and recurrence.

RESULTS

Age was significantly lower in the N1a and N1b groups compared to N0 (45 vs. 40.5 vs. 49 years, respectively; p = 0.002). Tumour size was smaller in the N1a group compared to N1b group (9 vs. 11.8 mm; p <0.01). The mean number of metastatic LNs at initial surgery was higher in the N1b compared to N1a group (6.6 vs. 3; p = 0.001), and in the recurrent compared to the non-recurrent group (7 versus 3.9; p <0.01). The recurrence rate was higher in the N1b group than the N1a and N0 groups (25% vs. 2.4% vs. 1.4%, respectively; p = 0.001).

CONCLUSIONS

Lymph node stage N1b at diagnosis, and having five or more metastatic nodes, are strong risk factors for cancer recurrence and decreased disease-free survival in sPTC. The management of patients with sPTC should include thorough lymph node mapping for optimal treatment and individual risk stratification.

Perineural Invasion in Papillary Thyroid Cancer: A Rare Indicator of Aggressive Disease

BACKGROUND

Perineural invasion (PNI) is associated with aggressive tumor behavior, increased locoregional recurrence, and decreased survival in many carcinomas. However, the significance of PNI in papillary thyroid cancer (PTC) is incompletely characterized.

METHODS

Patients diagnosed with PTC and PNI from 2010-2020 at a single, academic center were identified and matched using a 1:2 scheme to patients without PNI based on gross extrathyroidal extension (ETE), nodal metastasis, positive margins, and tumor size (±4 cm). Mixed and fixed effects models were used to analyze the association of PNI with extranodal extension (ENE)-a surrogate marker of poor prognosis.

RESULTS

In total, 78 patients were included (26 with PNI, 52 without PNI). Both groups had similar demographics and ultrasound characteristics preoperatively. Central compartment lymph node dissection was performed in most patients (71%, n = 55), and 31% (n = 24) underwent a lateral neck dissection. Patients with PNI had higher rates of lymphovascular invasion (50.0% vs. 25.0%, p = 0.027), microscopic ETE (80.8% vs. 44.0%, p = 0.002), and a larger burden [median 5 (interquartile range [IQR] 2-13) vs. 2 (1-5), p = 0.010] and size [median 1.2 cm (IQR 0.6-2.6) vs. 0.4 (0.2-1.4), p = 0.008] of nodal metastasis. Among patients with nodal metastasis, those with PNI had an almost fivefold increase in ENE [odds ratio [OR] 4.9 (95% confidence interval [CI] 1.5-16.5), p = 0.008] compared with those without PNI. More than a quarter (26%) of all patients had either persistent or recurrent disease over follow-up (IQR 16-54 months).

CONCLUSIONS

PNI is a rare, pathologic finding that is associated with ENE in a matched cohort. Additional investigation into PNI as a prognostic feature in PTC is warranted.

Surgical treatment and prognosis values of extranodal extension to recurrent laryngeal nerve in papillary thyroid carcinoma

PURPOSE

Recurrent laryngeal nerve (RLN) invasion by extranodal extension (ENE) is a rare condition that may occur in papillary thyroid cancer (PTC), and it has never been characterised in the literature.Our research aims to investigate the clinical significance of ENE to RLN including its effect on vocal cord function, relationship with the aggressive behaviour of PTC, and optimal surgical methods.

METHODS

A total of 3119 patients, including 2868 patients without RLN invasion, 251 patients with RLN invasion [categorised into the ENE invasion group (n = 55) and extrathyroidal extension (ETE) invasion group (n = 196)] were analyzed retrospectively. Data on clinicopathological characteristics, vocal cord paralysis (VCP), postoperative complications, surgical methods, rates of recurrence and metastasis were collected. Predictive disease-free survival (DFS) was analysed using the Kaplan-Meier method.

RESULTS

The ENE invasion group showed a similar rate of VCP and DFS compared with the ETE invasion group (P = 0.15, P = 0.38, respectively). Sharp separation applied on the invaded nerves preserves the visual integrity of the RLN without significantly reducing the DFS (P > 0.05). ETE or ENE to RLN, lymph nodes metastasis (LNM), and T4 stage were independent factors for total recurrence [P = 0.04, hazard ratio (HR), 1.97 (1.04-3.75); P = 0.00, HR, 4.63 (2.24-9.54); P = 0.00, HR, 3.63 (1.94-6.77); P = 0.00, HR, 6.1 (3.24-11.50)]. RLN invasion, both by ETE or ENE, was significantly associated with reduced DFS (P = 0.00; P = 0.00, respectively).

CONCLUSIONS

ENE to RLN, while rare, has not previously been well-studied. Our interesting premise and important findings including ENE to RLN has the same poor prognostic impact on recurrence as does invasion of the RLN by ETE and surgical management for the invaded RLN that preserves its visual integrity without compromising DFS. Those novel findings indicate that ENE to RLN could be considered as an additional factor beyond post-operative disease status and risk stratification, and it would be a valuable addition to further individualise treatment/surveillance for PTC.

Minimal extrathyroidal extension is associated with lymph node metastasis in single papillary thyroid microcarcinoma: a retrospective analysis of 814 patients

Background

Extrathyroidal extension (ETE) is considered a major prognostic factor in papillary thyroid carcinoma (PTC). Patients with gross ETE are at increased risk of recurrence and mortality. The importance of minimal ETE still remains controversial, especially in patients with papillary thyroid microcarcinoma (PTMC). The purpose of this study was to evaluate the association between ETE and lymph node (LN) metastasis in single PTMC.

Methods

A retrospective analysis was performed of 1994 patients underwent thyroidectomy for PTC between 2012 and 2016 in a single institution. Patients with combined thyroid carcinoma of other types and those who underwent completion thyroidectomy were excluded. After further exclusion of PTC larger than 1 cm and multifocal tumors, 814 patients with single PTMC were included in the study.

Results

72.9% patients had no ETE, 25.1% minimal ETE, and 2.1% gross ETE. ETE was associated with lymphatic invasion, perineural invasion, and vascular invasion. Patients with minimal and gross ETE were also more likely to have LN metastasis, including lateral neck metastasis, compared to those without ETE. In univariate analysis, LN metastasis was associated with male gender, conventional PTC, lymphatic invasion, perineural invasion, and ETE. In multivariate analysis, male gender (OR = 1.987; 95% CI 1.369–2.884), lymphatic invasion (OR = 4.389; 95% CI 1.522–12.658), perineural invasion (OR = 6.545; 95% CI 1.262–33.948), and minimal ETE (OR = 1.852; 95% CI 1.298–2.643) were found to be independent risk factors of LN metastasis.

Conclusions

Minimal ETE is associated with LN metastasis in single PTMC, compared to no ETE. Minimal ETE should be considered in the management of patients with single PTMC, whether surgical or during active surveillance.

Does macroscopic extrathyroidal extension to the strap muscles alone affect survival in papillary thyroid carcinoma?

BACKGROUND

Macroscopic extrathyroidal extension to structures adjacent to the thyroid gland is one of the most important predictors of survival in papillary thyroid carcinoma. However, the prognostic significance of macroscopic extrathyroidal extension to strap muscles alone is unknown. The aim of this study is to determine the impact on survival in patients with macroscopic extrathyroidal extension to strap muscles alone compared to those with no macroscopic extrathyroidal extension and macroscopic extrathyroidal extension involving other adjacent structures.

METHODS

After institutional review board approval, adult papillary thyroid carcinoma patients were identified from an institutional database of 6,259 patients undergoing initial surgery for well-differentiated thyroid carcinoma from 1986 to 2015. Patients were classified as having no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, or macroscopic extrathyroidal extension to other adjacent structures. Disease-specific survival was calculated using the Kaplan-Meier method and groups were compared using the log-rank test. A P value < .05 was considered statistically significant and significant factors were used in a Cox proportional hazard model to predict disease-specific survival.

RESULTS

There were 5,880 patients included in the analysis; 5,485 patients (93.3%) in the no macroscopic extrathyroidal extension group, 179 (3.0%) in the macroscopic extrathyroidal extension to strap muscles alone group and 216 (3.7%) in the macroscopic extrathyroidal extension involving other adjacent structures group. With a median follow-up of 64 months, the estimated 10-year disease-specific survival for patients with no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, and macroscopic extrathyroidal extension involving other adjacent structures were 98.9%, 95.7%, and 83.7%, respectively (P < .0001). In the ≥55-year-old cohort, the estimated 10-year disease-specific survival for patients with no macroscopic extrathyroidal extension, macroscopic extrathyroidal extension to strap muscles alone, and macroscopic extrathyroidal extension involving other adjacent structures were 97.6%, 89.3%, and 68.1%, respectively (P <.0001). After controlling for pathological nodal stage and distant metastasis stage, extent of extrathyroidal extension remained an independent predictor of disease-specific survival; patients with macroscopic extrathyroidal extension to strap muscles alone had a 3.3-fold increased likelihood of a disease-specific death compared to no macroscopic extrathyroidal extension patients (hazard ratio 3.294; 95% confidence interval 1.076-10.086, P < .0368).

CONCLUSION

In our study, patients aged ≥55 years with papillary thyroid carcinoma and macroscopic extrathyroidal extension to strap muscles alone appear to have an increased likelihood of a disease-specific death compared to patients with no macroscopic extrathyroidal extension.

Extranodal extension is an independent predictor of extensive nodal metastasis in T1 papillary thyroid cancer

PURPOSE

Extensive lymph node metastasis (ELM) can occur in some patients with T1 papillary thyroid cancer (PTC). However, the risk factors for ELM in patients with T1 PTC have not been fully explored. In this study, we aimed to examine the association between extranodal extension (ENE) and ELM in patients with T1 PTC.

PATIENTS AND METHODS

We identified 645 consecutive patients who had T1 PTC initially resected at our centre. Clinical and pathological data were reviewed. Univariate and multivariate logistic regression analyses were performed to identify the risk factors for ELM.

RESULTS

ELM was identified in 3.9% of T1 PTC patients, and ENE was identified in 8.1% of patients. ENE was associated with male sex, large tumour size, more positive nodes, and comprehensive surgical treatment. In multivariate analysis, three variables were independently associated with ELM, including ENE (odds ratio [OR], 11.15; 95% confidence interval [CI], 4.54 to 27.30; P < 0.001), age (OR, 0.96; 95% CI, 0.93 to 0.99; P = 0.022), and tumour size (OR, 1.18; 95% CI, 1.06 to 1.31; P = 0.002). Bilateral multifocality and sex were not independently associated with ELM.

CONCLUSION

ENE is a strong independent predictor of ELM in patients with T1 PTC. Patients with ENE-positive nodes might need extensive neck dissection.

PRDM16 Inhibits Cell Proliferation and Migration via Epithelial-to-Mesenchymal Transition by Directly Targeting Pyruvate Carboxylase in Papillary Thyroid Cancer

PRDM16 (known as MEL1), a member of the PR domain zinc finger family, has been implicated in multiple biological processes, including cancers. It is not clear yet whether PRDM16 is involved in tumor progress of papillary thyroid cancer (PTC). We identified the PRDM16 expression level in PTC tissues by qRT-PCR and analyzed its relationship with clinical characteristics in both Fudan University Shanghai Cancer Center (FUSCC) and TCGA cohorts. We tested the function of PRDM16 in PTC cells both in vivo and in vitro. We found a direct downstream target of PRDM16, pyruvate carboxylase (PC), by RNA-sequencing, rescue experiments, luciferase assay, and chromatin immunoprecipitation assay. PRDM16 was downregulated in papillary thyroid cancer tissues and was significantly related with lymph node metastases and extrathyroidal extension in both FUSCC and TCGA cohorts. Overexpression of PRDM16 could attenuate proliferation and migration of PTC cells via inhibiting the epithelial-to-mesenchymal transition process. PC was upregulated in papillary thyroid cancer tissues. Knockdown of PC could inhibit proliferation and migration in TPC-1 and K1 cells. The repression effect on cell proliferation and migration from PRDM16 was PC dependent. PRDM16 could directly bind to the PC promoter and inhibit its expression at the transcription level. Moreover, the mRNA expression level of PRDM16 and PC was negatively related in human PTC tissues. In conclusion, PRDM16 exhibited an antitumor effect and EMT inhibition function in PTC by directly binding with the PC promoter. PRDM16 may be a novel therapeutic target in papillary thyroid cancer.

Predictive Value of Gross Extranodal Extension for Differentiated Thyroid Carcinoma Persistence/Recurrence

OBJECTIVE

We systematically investigated the predictive value of gross extranodal extension (gENE) for differentiated thyroid carcinoma persistence/recurrence.

STUDY DESIGN

Retrospective study.

SETTING

A tertiary care hospital.

METHODS

This study was divided into 2 groups according to gENE status: the gENE group and non-gENE group. We compared the disease persistence/recurrence rates of these 2 groups in the entire cohort and by individual risk group (intermediate/high risk), analyzed whether gENE was an independent risk factor for disease persistence/recurrence, and explored the impact of gENE-specific features on disease persistence/recurrence.

RESULTS

There were 989 patients who satisfied the inclusion criteria: 57 patients in the gENE group and 932 in the non-gENE group. The disease persistence/recurrence rate of the gENE group was higher than that of the non-gENE group in the entire cohort and by individual risk group (P < .05 for each). Unexpectedly, the outcomes of the gENE group with intermediate risk were similar to those of the non-gENE group with high risk (P = .72). For the entire cohort, gENE was an independent predictor for disease persistence/recurrence (odds ratio, 2.89; 95% CI, 1.39-6.00; P = .005). Specific features of gENE (P > .05 for each) were not related to disease persistence/recurrence.

CONCLUSION

Patients with gENE and intermediate risk might be regraded as high risk. Specific features of gENE have no impact on disease persistence/recurrence.

Enemy Beyond the Wall: Clinicopathological Features of Intrathyroidal Papillary Thyroid Carcinoma (T1-T3a) That Metastasize to Lymph Nodes Without Extrathyroidal Extension

The aim of this study was to determine the clinicopathological features of papillary thyroid carcinomas (PTC) without extrathyroidal extension (ETE) and with lymph node metastasis (LNM). PTC > 1 cm increased the risk of LNM by 2.161 times compared to papillary thyroid microcarcinoma. The risk increased by 3.774 times in males and 1.553 times in the presence of multifocality. Presence of vascular invasion (VI) increased the risk of LNM by 3.093 times in patients without capsular invasion (CI). Clinicians should be careful about possible LNM in patients with large primary tumor diameter, multifocal tumors, CI and VI.

Extranodal Extension Is an Independent Prognostic Factor in Papillary Thyroid Cancer: A Propensity Score Matching Analysis

PURPOSE

To investigate the prognostic significance of extranodal extension (ENE) in papillary thyroid cancer (PTC).

METHODS

Seven hundred forty-three PTC patients were enrolled in the study from January 2014 to December 2017. The patients were dichotomized according to the presence of ENE. Logistic analysis was used to compare differences between the two groups. Kaplan-Meier (K-M) curve and propensity score matching (PSM) analyses were used for recurrence-free survival (RFS) comparisons. Cox regression was performed to analyze the effects of ENE on RFS in PTC.

RESULTS

Thirty-four patients (4.58%) had ENE. Univariate analysis showed that age, tumor size, extrathyroidal extension, and nodal stage were associated with ENE. Further logistic regression analysis showed that age, extrathyroidal extension, and nodal stage remained statistically significant. Evaluation of K-M curves showed a statistically significant difference between the two groups before and after PSM. Cox regression showed that tumor size and ENE were independent risk factors for RFS.

CONCLUSIONS

Age ≥55 years, extrathyroidal extension, and lateral cervical lymph node metastasis were identified as independent risk factors for ENE. ENE is an independent prognostic factor in PTC.

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.

Differentiated Thyroid Cancer: The Role of ATA Nodal Risk Factors in N1b Patients

OBJECTIVES/HYPOTHESIS

Nodal involvement is frequent in patients with differentiated thyroid cancers (DTCs), but its prognostic relevance is not univocal. Some characteristics of nodal metastases can increase the risk of recurrence. We attempted to quantify the impact on survival of nodal factors included in the American Thyroid Association (ATA) risk stratification system in N1b patients with DTC.

STUDY DESIGN

Retrospective study.

METHODS

A retrospective analysis of patients affected by DTC who underwent therapeutic lateral neck dissection (ND) was performed. The impact on the prognosis of the number of positive lymph nodes (LNs), dimension of nodal metastasis, and microscopic and macroscopic extranodal extension (miENE and maENE, respectively) was investigated.

RESULTS

The study included 347 N1b patients who underwent 401 therapeutic lateral NDs. Mean number of positive LNs was nine, mean nodal ratio was 0.27, and mean diameter of metastasis was 15.5 mm. ENE was detected in 25.9% of patients (22.5% miENE and 3.5% maENE). In univariate analysis, the presence of maENE had an impact on disease specific survival (DSS) (P = .023); increasing number of positive LNs affected DSS and locoregional control (LRC) (P = .009 and =.006, respectively); increasing metastatic node dimension was a risk factors for overall survival, DSS, and metastases free survival (MFS) (P = .05, =.013 and =.016). In multivariate analysis, number of positive LNs and LN dimension were independent risk factors for LRC and MFS, respectively (HR 1.1, P = .028; HR 1.1, P = .026).

CONCLUSIONS

In our analysis on a cohort of N1b patients, the number of positive LNs and LN dimension were confirmed as independent risk factors for locoregional and distant recurrence, respectively.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E1029-E1034, 2021.

Extrathyroidal Extension is an Important Predictor of Regional Lymph Node Metastasis in Pediatric Differentiated Thyroid Cancer

Introduction: The American Joint Committee Cancer (AJCC) TNM system predicts survival in patients with differentiated thyroid cancer (DTC). In the eighth edition of the AJCC TNM, microscopic extrathyroidal extension (microETE) was removed and tumor size >4 cm was maintained in the definition of T3 disease to reduce unnecessarily aggressive therapy for adults at low risk of death from DTC. In pediatric patients where DTC survival rates are high, the AJCC TNM is used to identify patients at increased risk of persistent, postsurgical disease, to identify patients who benefit from radioactive iodine therapy. The aim of this study was to assess the correlation of microETE with cervical lymph node (LN) metastasis in pediatric patients and to determine if tumor size or microETE is more informative in predicting regional LN disease. Methods: Patients with DTC <19 years of age at the time of thyroidectomy with AJCC T3 tumors (seventh edition) and the presence of LNs on the surgical specimen were included in this retrospective chart review. Pathological findings were confirmed by pathologist review. Results: Forty-five patients with AJCC T3 designation were included, 34 with microETE and 11 without microETE. Of those with microETE, 32 (94.1%) demonstrated regional LN metastasis compared with 5/11 patients (45.5%) without microETE (p = 0.001). In addition, microETE was associated with lateral neck LN metastasis (p = 0.004), bilateral disease (p = 0.001), and tumor multifocality (p = 0.003). Patients with microETE had smaller tumors (median = 2.5 cm, interquartile range [IQR]: 1.6-4.5) compared with patients without microETE (median = 5 cm, IQR: 4.2-5.4; p = 0.02). No increased association was found between microETE and vascular invasion, distant metastasis, or persistent/recurrent disease. Conclusions: In pediatric patients with DTC, microETE is a strong predictor of LN metastasis when compared with tumor size. For patients who do not undergo prophylactic central neck LN dissection, the presence of microETE predicts an increased risk of postsurgical disease and should be included in future revisions of the American Thyroid Association pediatric risk stratification categories.

Prognostic value of tumor size and minimal extrathyroidal extension in papillary thyroid carcinoma

BACKGROUND

Tumour size and extrathyroidal extension (ETE) may impact papillary thyroid carcinoma (PTC) outcomes. We therefore examined the prognostic value of tumour size and ETE for predicting posttreatment recurrence in PTC patients.

METHODS

A total of 2,902 patients who underwent thyroidectomy for previously untreated T1-T3 PTC (7th edition American Joint Committee on Cancer) at our tertiary referral center were included. Univariate and multivariate Cox proportional hazard regression analyses were used to determine significant factors predictive of posttreatment recurrence-free survival (RFS).

RESULTS

In univariate analysis, tumour factors (including tumour size, multifocality, ETE, and lymphovascular invasion), nodal factors (including positive lymph node number, lymph node ratio, and extranodal extension), and MACIS (metastases, age, completeness of resection, invasion, and size) scores were significantly associated with RFS outcomes (P < 0.001). In multivariate analysis, tumour size >4 cm (P < 0.001) and multifocality (P = 0.038) were the independent factors of RFS. Nodal factors and MACIS scores were also independent factors of RFS.

CONCLUSION

Tumour size impacts RFS after thyroidectomy in T1-T3 PTC patients.

Proposal for an extended pTNM classification of thyroid carcinoma : Commentary on deficits of the 8th edition of the TNM classification

In the 8th edition of the TNM classification of thyroid carcinomas, which was introduced in 2017, carcinomas with minimal extrathyroidal extension are no longer mentioned, which might cause problems. These tumors were explicitly categorized in previous TNM classifications (5-7th editions). Studies on the prognostic relevance of minimal extrathyroidal extension have shown conflicting results. Moreover, the vast majority of these studies retrospectively analyzed only subgroups of thyroid carcinomas (e.g. differentiated thyroid carcinoma, papillary thyroid carcinoma). The proposed subcategorization of the current TNM classification (8th edition) ensures the continuity of the parameter minimal extrathyroidal extension within the TNM categorization of thyroid carcinomas and also offers the possibility to prospectively analyze in a standardized manner the potential biological relevance of minimal extrathyroidal extension in relation to tumor categories (T/pT category).

Predictive factors for central lymph node and lateral cervical lymph node metastases in papillary thyroid carcinoma

BACKGROUND

Central lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC) is common. But the association between primary tumor characteristics and specific features of metastatic lymph nodes in PTC has not been fully identified. Determining risk factors for LNM may help surgeons determine rational extent of lymph node dissection.

METHODS

Data from 432 patients who underwent thyroidectomy with cervical lymph node dissection for PTC were retrospectively analyzed. The relationships between LNM to central compartment or lateral compartment and clinicopathologic factors were analyzed. Cox regression model was used to determine the risk factors for recurrence-free survival (RFS).

RESULTS

Central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) were found in 216 (50.0%) and 65 (15.0%) patients, respectively. In the multivariate analysis for CLNM, patients < 45 years of age (OR 2.037, 95% CI 1.388-2.988, P < 0.001), extrathyroidal invasion (OR: 2.144, 95% CI 0.824-5.457, P = 0.011), vascular invasion (OR 13.817, 95% CI 1.694-112.693, P = 0.014), LLNM (OR 2.851, 95% CI 1.196-6.797, P = 0.014) and TNM Stage III-IV (OR 465.307, 95% CI 113.903-1900.826, P < 0.001) were independent predictors for high prevalence of CLNM. In the multivariate analysis for LLNM, tumor size more than 1cm (OR 3.474, 95% CI 1.728-6.985, P < 0.001) and CLNM (OR 5.532, 95% CI 2.679-11.425, P < 0.001) were independent predictors for high prevalence of LLNM. Moreover, tumor with T3-T4 stage, extrathyroidal invasion and CLNM were the significant factors related to the RFS.

CONCLUSION

For patients with pre-operative risk factors of LNM, an accurate preoperative evaluation of central compartment or lateral compartment is needed to find suspicious lymph nodes. And prophylactic lymph node dissection should be performed in patients with high risk of CLNM. Moreover, we suggest performing close follow-up for patients with high risk of RFS.

Risk of recurrence in a homogeneously managed pT3-differentiated thyroid carcinoma population

BACKGROUND

International guidelines for the management of differentiated thyroid cancers are based on the 7th TNM classification: pT3 tumors are defined as differentiated thyroid cancers (DTCs) measuring more than 4 cm in their greatest dimension that are limited to the thyroid or any tumor with minimal extrathyroidal extension (ETE; sternothyroid muscle or perithyroid soft tissues). Differences in clinicohistological features and prognosis among patients with pT3 tumors remain controversial, and studies regarding pT3 subgroups are lacking.

OBJECTIVE

To analyze the prognosis of four subgroups of pT3 DTCs (papillary, PTC; or follicular, FTC).

DESIGN AND SETTING

The data of patients who underwent surgery for pT3 DTC between 1978 and 2015 in a surgical department specialized in endocrine surgery were reviewed. Patients were classified into four groups as follows: the pT3a (≤ 10 mm with ETE), pT3b (10-40 mm with ETE), pT3c (> 40 mm without ETE), and pT3d groups (> 40 mm with ETE). Recurrence-free survival (RFS) was analyzed using the Kaplan-Meier method.

RESULTS

One thousand eighty-eight patients with pT3 DTC were included, of whom 311 (29%) had pT3a; 548 (50%), pT3b; 165 (15%), pT3c; and 64 (6%), pT3d. For the 916 patients with lymph node (LN) dissection, metastatic LNs were more frequent in the pT3b and pT3d groups (61 and 61%, respectively) than in the other groups (44% pT3a and 10% pT3c; p < 0.001). During the median follow-up period of 9 years (range, 2-38 years), recurrence occurred in 169 patients with T3 tumors (16%), including 18 with pT3a (6%), 100 with pT3b (18%), 20 with pT3c (12%), and 31 with pT3d (48%). In a multivariate analysis, LN metastases (< 0.0001), extranodal extension (p = 0.03), FTC (vs. PTC) (p = 0.006), pT3b (p = 0.016), and pT3d (p = 0.047) were associated with an increased risk of recurrence. The 5-year RFS rates were 94.5, 82.2, 91.1, and 50.3% for the pT3a, pT3b, pT3c, and pT3d groups, respectively (p < 0.01).

CONCLUSION

Except for microcarcinoma, the risk of LN involvement is high and similar for the DTC patients with minimal ETE, regardless of the size of the tumor. The association of a tumor size of > 4 cm and ETE are associated with a poor prognosis and should justify the classification of these cases as a high-risk group. Other pT3 patients with no LN metastases could be individualized as a low-risk group.

[Proposal for an extended pTNM classification of thyroid carcinoma : Commentary on deficits of the 8th edition of the TNM classification (German version)]

In the 8th edition of the TNM classification of thyroid carcinomas, which was introduced in 2017, carcinomas with minimal extrathyroidal extension are no longer mentioned, which might cause problems. These tumors were explicitly categorized in previous TNM classifications (5-7th editions). Studies on the prognostic relevance of minimal extrathyroidal extension have shown conflicting results. Moreover, the vast majority of these studies retrospectively analyzed only subgroups of thyroid carcinomas (e.g. differentiated thyroid carcinoma, papillary thyroid carcinoma). The proposed subcategorization of the current TNM classification (8th edition) ensures the continuity of the parameter minimal extrathyroidal extension within the TNM categorization of thyroid carcinomas and also offers the possibility to prospectively analyze in a standardized manner the potential biological relevance of minimal extrathyroidal extension in relation to tumor categories (T/pT category).

Latero-cervical lymph node metastases (N1b) represent an additional risk factor for papillary thyroid cancer outcome

PURPOSE

Papillary thyroid carcinoma (PTC), the most common thyroid cancer histotype, has a good prognosis even when spread to the neck lymph node (LN). The prognostic role of LN metastases' location is still controversial. The aim of the present study was to evaluate the clinical relevance of the number and location of LN metastases at presentation in PTCs.

METHODS

This retrospective study included a consecutive series of 1653 PTC patients followed for a mean period of 5.9 years in a referral thyroid cancer clinic. All patients have undergone thyroidectomy with the dissection of at least six LNs. According to the LN status, patients were subdivided into 569 N0 (34.4%), 644 N1a (39.0%, central compartment) and 440 N1b (26.6%, latero-cervical compartment).

RESULTS

Age at diagnosis was significantly lower in N1b (39.8, IQR 30.7-51.6) and N1a (40.1, IQR 31.3-50.1) than in N0 (44.7, IQR 36.6-55.0 yrs). The male gender was more prevalent in N1b than in N1a and N0 (F/M = 1.9/1, 4.0/1 and 5.5/1, respectively). Persistent/recurrent disease at last control was significantly more frequent in N1b (29.8%) than in N1a (14.3%), and in N1a than in N0 (4.2%) (p < 0.01 for all). Also, distant metastases were significantly (p < 0.001) more frequent in N1b (14.1%) than in N1a (4.3%) and N0 (1.6%). LN metastases' number (>5) was a significant risk factor for persistent/recurrent disease only for N1a patients.

CONCLUSIONS

These data indicate that persistent/recurrent disease and distant metastases are significantly more frequent in patients with latero-cervical LN (N1b) metastases and that the LN location should be used for a better postsurgical risk stratification.

Extranodal extension of lymph node metastasis as a prognostic indicator of recurrence and survival in papillary thyroid carcinoma

BACKGROUND AND OBJECTIVES

Stratification of extranodal extension (ENE) extent has the potential to improve the accuracy of risk estimations in papillary thyroid carcinoma (PTC). This study examined the prognostic importance of nodal factors, including ENE, in PTC patients.

METHODS

This study enrolled 2071 consecutive patients with treatment-naïve PTC who underwent thyroidectomy between 2006 and 2010. Microscopic/macroscopic ENE was determined by pathological and operative findings. Univariate and multivariate analyses were used to identify the relationship of factors with recurrence and survival in all study patients and in the node-positive subset.

RESULTS

Of 2071 patients, 975 (47.1%) had positive lymph nodes, and 271 (13.1%) and 70 (3.4%) had microscopic and macroscopic ENE, respectively. During a median follow-up of 96 months, 114 (5.5%) patients had post-treatment recurrence. Multivariate analyses showed that, in all patients, the number of positive nodes, lymph node ratio, ENE status, and ATA risk group were independent variables affecting recurrence (P < 0.05). T4 and macroscopic ENE were independent variables associated with shorter overall survival (P < 0.05). Macroscopic ENE was significantly associated with macroscopic extrathyroidal extension.

CONCLUSION

Macroscopic ENE has a significant adverse impact on recurrence and survival after treatment for PTC. ENE is considered a high risk factor for recurrence.

Extrathyroidal Extension Is Associated with Compromised Survival in Patients with Thyroid Cancer

BACKGROUND

Patients with thyroid cancer who have extrathyroidal extension (ETE) are considered to have more advanced tumors. However, data on the impact of ETE on patient outcomes remain limited. The purpose of this study was to evaluate the association between ETE and survival in patients with thyroid cancer.

METHODS

The National Cancer Database (1998-2012) was queried for all adult patients with differentiated thyroid cancer and medullary thyroid cancer. Patients were divided into three groups: no ETE (T1 and T2 tumors), minimal ETE (T3 tumors <4 cm), and extensive ETE (T4 tumors <4 cm). Patient demographic, clinical, and pathologic factors were evaluated for all patients. A Cox proportional hazards model was developed for each histology to identify factors associated with survival.

RESULTS

In total, 241,118 patients with differentiated thyroid cancer met the inclusion criteria; 86.9% had no ETE, 9.1% minimal ETE, and 4.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.4 cm vs. 1.8 cm and 2.0 cm, respectively), lymphovascular invasion (8.6% vs. 28.0% and 35.1%, respectively), positive margins after thyroidectomy (6.1% vs. 35.2% and 45.9%, respectively), and regional lymph node metastases (32.5% vs. 67.0% and 74.6%, respectively; all p < 0.01). After adjustment, minimal ETE (hazard ratio [HR] = 1.13; p < 0.01) and extensive ETE (HR = 1.74; p < 0.01) were associated with compromised survival for patients with differentiated thyroid cancer. In total, 3415 patients with medullary thyroid cancer met the inclusion criteria; 87.9% had no ETE, 7.1% minimal ETE, and 5.0% extensive ETE. Compared with patients with no ETE, patients with minimal and extensive ETE were more likely to have larger tumors (1.7 cm vs. 2.2 cm and 2.2 cm, respectively), lymphovascular invasion (19.2% vs. 68.9% and 79.3%, respectively), positive margins after thyroidectomy (5.8% vs. 44.1% and 51.9%, respectively), and regional lymph node metastases (39.0% vs. 90.5% and 94.4%, respectively; all p < 0.01). After adjustment, extensive ETE (HR = 1.63; p = 0.01) was associated with compromised survival for patients with medullary thyroid cancer.

CONCLUSION

In patients with differentiated and medullary thyroid cancers, ETE is associated with compromised survival. Given these findings, ETE should be included in the thyroid cancer treatment guidelines.

Prognostic indicators for papillary thyroid carcinoma

Differentiated thyroid cancer (DTC) includes more than 90% of all thyroid carcinoma and its incidence is growing, mainly due to an increase in the incidence of papillary thyroid cancer (PTC) for the widespread use of neck ultrasonography. Areas covered: Several prognostic factors should be considered during the management of PTC in order to provide the most effective treatment. The most important prognostic factors in PTC include personal and pathological features such as patient's age, gender, hystotype, tumor size, extrathyroidal extension, lymph node involvement, presence of local or distant metastases and molecular analyses. We performed a search in the PubMed database for studies published in English since 1960 using the terms: 'thyroid cancer', 'prognostic factors', 'age', 'gender', 'hystotype', 'tumor size', 'extrathyroidal extension', 'lymph node', 'metastases' and 'molecular analyses'. Expert commentary: Prognostic factors can guide clinicians during the treatment and follow-up of DTC patients, but it is now evident that the risk of recurrence or death must be evaluated periodically, on the basis of individual risk, according to the response to initial therapy or the subsequent therapy required during follow-up.

Predictive Factors for Active Surveillance of Subcentimeter Thyroid Nodules with Highly Suspicious US Features

PURPOSE

This study was designed to assess the outcomes of subcentimeter thyroid nodules with highly suspicious ultrasonography (US) features and to investigate the predictive factors associated with malignancy and aggressive biological behavior to determine appropriate candidate factors for active surveillance.

METHODS

Between June 2011 and December 2013, 1866 subcentimeter thyroid nodules with highly suspicious US features that were subjected to US-guided fine needle aspiration and subsequent surgery or US follow-up of at least 2 years were evaluated. A multivariate logistic regression analysis was performed to identify independent clinical characteristics and US features associated with the malignancy rate and aggressive biological behavior.

RESULTS

Of the 1866 subcentimeter thyroid nodules, 821 (44.0%) were benign and 1045 (56.0%) were malignant. Age younger than 45 years, presence of microcalcification, and a taller than wide shape on US were associated independently with malignancy in the subcentimeter thyroid nodules (P < 0.05). Of 1041 evaluated papillary microcarcinomas, a multivariate analysis revealed that male gender, presence of microcalcification, and a taller than wide on US were independently associated with lymph node metastasis and ATA intermediate risk (P < 0.01).

CONCLUSIONS

Age younger than 45 years, male gender, and subcentimeter thyroid nodules exhibiting microcalcification, and a taller than wide shape on US might be not good candidate factors for active surveillance.

Prognostic Value of Extranodal Extension in Thyroid Cancer: A Meta-Analysis

PURPOSE

Thyroid cancer is the most common endocrine cancer and its incidence has continuously increased in the last three decades all over the world. We aimed to evaluate the prognostic value of extranodal extension (ENE) of thyroid cancer.

MATERIALS AND METHODS

We performed a systematic search of MEDLINE (from inception to June 2014) and EMBASE (from inception to June 2014) for English-language publication. The inclusion criteria were studies of thyroid cancer that reported the prognostic value of ENE in thyroid cancer. Reviews, abstracts, and editorial materials were excluded, and duplicate data were removed. Two authors performed the data extraction independently.

RESULTS

6 studies including 1830 patients were eligible for inclusion in the study. All patients included in the meta-analysis had papillary thyroid cancer (PTC). Recurrence-free survival was analyzed based on 3 studies. The pooled hazard ratio for recurrence was 2.01 [95% confidence interval (CI) 1.19-3.40, p=0.009]. Disease-specific survival was analyzed based on 3 studies with 973 patients. Patients of PTC with ENE showed 3.37-fold higher risk of death from the disease (95% CI 1.55-7.32, p=0.002).

CONCLUSION

ENE should be considered to be a poor prognostic marker in thyroid cancer; such knowledge might improve the management of individual patients. This might facilitate the planning of appropriate ablation therapy and tailored patient follow-up from the beginning of treatment.

Differences in the Recurrence and Survival of Patients with Symptomatic and Asymptomatic Papillary Thyroid Carcinoma: An Observational Study of 11,265 Person-Years of Follow-Up

BACKGROUND

Papillary thyroid carcinoma (PTC) generally has an indolent course and favorable prognosis. However, an optimal treatment strategy for asymptomatic PTC is not clear. We compared the recurrence and survival outcomes of patients with asymptomatic and symptomatic PTC and identified the associated risk factors.

MATERIALS AND METHODS

Patients with previously untreated PTC of size ≤2 cm and who underwent curative surgery were included in this analysis. Asymptomatic PTC was defined as a tumor detected only by ultrasonography, computed tomography (CT), magnetic resonance imaging, and/or ¹⁸F-fluorodeoxyglucose positron emission tomography/CT. Clinical factors, operative and pathologic findings, and posttreatment outcomes were compared between the aforementioned two groups. Univariate and multivariate analyses were performed to identify the factors associated with recurrence-free survival (RFS) and overall survival (OS).

RESULTS

Out of 1419 patients, 1259 patients (88.7%) were asymptomatic. Patients with symptomatic PTC had significantly larger tumor size, palpability, extrathyroidal extension, high tumor and node stages, and were more likely to undergo treatment with radioactive iodine therapy compared with patients with asymptomatic PTC (p < 0.05 each). Recurrence was significantly higher in the symptomatic PTC group than in the asymptomatic group (p < 0.001). Asymptomatic PTC was an independent predictor of RFS and OS and had higher five-year rates than those associated with symptomatic tumors: 97.3% and 90.6% for RFS (p < 0.001) and 99.4% and 96.9% for OS (p < 0.001), respectively.

CONCLUSION

Symptomatic PTC is associated with higher recurrence and lower overall survival rates than asymptomatic PTC. Symptomatic PTC may require total thyroidectomy and close posttreatment surveillance.

Inter-Observer Variation in the Pathologic Identification of Minimal Extrathyroidal Extension in Papillary Thyroid Carcinoma

BACKGROUND

Extrathyroidal extension (ETE) is a significant prognostic factor in papillary thyroid carcinoma (PTC). Minimal extrathyroidal extension (mETE) is characterized by involvement of the sternothyroid muscle or perithyroid soft tissue, and is generally identified by light microscope examination. Patients with mETE, identified pathologically, are automatically upstaged to pT3. However, the prognostic implications of mETE have been a source of controversy in the literature. Moreover, there is also controversy surrounding the identification of mETE on pathological specimens. The objective of this study was to determine the level of agreement among expert pathologists in the identification of mETE in PTC cases.

METHODS

Eleven expert pathologists from the United States, Italy, and Canada were asked to perform a review of 69 scanned slides of representative permanent sections of PTC specimens. Each slide was evaluated for the presence of mETE. The pathologists were also asked to list the criteria they use to identify mETE.

RESULTS

The overall strength of agreement for identifying mETE was slight (κ = 0.14). Inter-pathologist agreement was best for perithyroidal skeletal muscle involvement (κ = 0.46, moderate agreement) and worst for invasion around thick-walled vascular structures (κ = 0.02, slight agreement). In addition, there was disagreement over the constellation of histologic features that are diagnostic for mETE, which affected overall agreement for diagnosing mETE.

CONCLUSIONS

Overall agreement for the identification of mETE is poor. Disagreement is a result of both variation in individual pathologists' interpretations of specimens and disagreement on the histologic criteria for mETE. Thus, the utility of mETE in staging and treatment of PTC is brought into question. The lack of concordance may explain the apparent lack of agreement regarding the prognostic significance of this pathologic feature.

Impact of microscopic extra-nodal extension (ENE) on locoregional recurrence following curative surgery for papillary thyroid carcinoma

BACKGROUND

The presence of microscopic extra-nodal extension (ENE) may increase locoregional recurrence (LRR) in papillary thyroid carcinoma (PTC). We aimed to evaluate the association between microscopic ENE, response to initial therapy and LRR risk following total thyroidectomy, therapeutic neck dissection, and radioactive iodine (RAI) ablation in PTC.

METHODS

Of the 369 eligible PTC patients, 264 (71.5%) did not have microscopic ENE (group I) while 105 (28.5%) did (group II). All presented with clinical nodal metastasis (cN1) and underwent therapeutic neck dissection and RAI ablation. Biochemical incompleteness meant post-ablation stimulated thyroglobulin (sTg) >10 ng/ml. Multivariate analyses were conducted to identify independent factors for LRR.

RESULTS

Biochemical incompleteness was significantly more common group II (43.8% vs. 17.4%, P < 0.05). The 10-year locoregional free-survival was significantly worse in group II than I (52.0% vs. 86.2%, P = 0.005). After adjusting for other significant factors, age <45 (P < 0.05), multifocality (P < 0.05), presence of ENE (P = 0.027) were independent risk factors of LRR. The number and size of positive lymph nodes were not independent factors.

CONCLUSIONS

Patients with microscopic ENE were significantly more likely to have biochemical incompleteness after initial therapy. After adjusting for other significant primary and nodal characteristics, microscopic ENE was an independent factor for LRR in patients with cN1. J. Surg. Oncol. 2016;113:526-531. © 2016 Wiley Periodicals, Inc.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Primary tumour characteristics predict the invasiveness of lymph node metastases in papillary thyroid carcinoma patients

OBJECTIVE

This study evaluated whether primary tumour characteristics are associated with specific features of metastatic lymph nodes in papillary thyroid carcinoma patients.

METHOD

A retrospective review of 411 patients with pathologically diagnosed cervical lymph node metastasis was conducted.

RESULTS

A metastatic lymph node focus size of at least 2 mm was independently associated with a primary tumour size of at least 1 cm (hazard ratio 1.962) and with male sex (hazard ratio 1.947). A number of at least five lymph node metastases was independently associated with a primary tumour size of at least 1 cm (hazard ratio 2.863), extrathyroidal extension (hazard ratio 1.737) and male sex (hazard ratio 1.689). Extranodal extension was independently associated with a primary tumour size of at least 1 cm (hazard ratio 2.288), extrathyroidal extension (2.201) and male sex (hazard ratio 1.733).

CONCLUSION

Primary papillary thyroid carcinoma characteristics are related to the pathological features of lymph node metastases.

Follicular cell-derived thyroid cancer

Follicular cell-derived thyroid cancers are derived from the follicular cells in the thyroid gland, which secrete the iodine-containing thyroid hormones. Follicular cell-derived thyroid cancers can be classified into papillary thyroid cancer (80-85%), follicular thyroid cancer (10-15%), poorly differentiated thyroid cancer (<2%) and undifferentiated (anaplastic) thyroid cancer (<2%), and these have an excellent prognosis with the exception of undifferentiated thyroid cancer. The advent and expansion of advanced diagnostic techniques has driven and continues to drive the epidemic of occult papillary thyroid cancer, owing to overdiagnosis of clinically irrelevant nodules. This transformation of the thyroid cancer landscape at molecular and clinical levels calls for the modification of management strategies towards personalized medicine based on individual risk assessment to deliver the most effective but least aggressive treatment. In thyroid cancer surgery, for instance, injuries to structures outside the thyroid gland, such as the recurrent laryngeal nerve in 2-5% of surgeries or the parathyroid glands in 5-10% of surgeries, negatively affect quality of life more than loss of the expendable thyroid gland. Furthermore, the risks associated with radioiodine ablation may outweigh the risks of persistent or recurrent disease and disease-specific mortality. Improvement in the health-related quality of life of survivors of follicular cell-derived thyroid cancer, which is decreased despite the generally favourable outcome, hinges on early tumour detection and minimization of treatment-related sequelae. Future opportunities include more widespread adoption of molecular and clinical risk stratification and identification of actionable targets for individualized therapies.

Intrathyroidal tumors presenting with extranodal extension: what are we missing?

Extranodal extension (ENE) is an indicator of poor prognosis in well-differentiated thyroid cancer (WDTC). We have demonstrated that extrathyroidal extension (ETE) predicts ENE in patients with positive lymph nodes, indicating concordance between primary tumor and lymph node biology. In an effort to determine if there were other histologic features of the primary tumors that indicated an aggressive biology, we examined a subset of patients with intrathyroidal (T1/T2) disease whose lymph nodes had ENE. A review was conducted from January 2004 to March 2013. The histologic features of ETE-negative/ENE-positive tumors (group A, 12 cases) were compared with a random sample of ETE-negative/ENE-negative node-positive patients (group B, 27 cases). Cases were reviewed for size, capsule presence, infiltration, sclerosis, lymphocytic thyroiditis (LT), psammoma bodies, lymphovascular invasion (LVI), perineural invasion (PNI), architecture/cytomorphology, and focality. Size was compared using the Mann-Whitney test, while the remaining features were compared using a Fischer exact test. The breakdown of pathologic features of groups A/B were as follows: 2.28 cm/1.46 cm mean tumor size, 90 %/67 % unencapsulated, 100 %/89 % infiltrative, 100 %/89 % sclerotic, 60 %/52 % LT, 30 %/59 % positive psammoma bodies, 0 %/11 % LVI, 0 %/4 % PNI, 90 %/96 % classic architecture, 50 %/44 % multifocal. Neither size (p = 0.072) nor the other nine histologic features examined reached statistical significance. None of the histologic features appeared to significantly predict ENE. Further examination of intrathyroidal tumors at a molecular level is necessary to determine if there are any identifiable features of intrathyroidal tumors that predict ENE and thus a more aggressive phenotype.