Clinical significance of extrathyroidal extension according to primary tumor size in papillary thyroid carcinoma

ATA risk stratification in papillary thyroid microcarcinoma has low positive predictive value when identifying recurrence

BACKGROUND

Rising incidence of papillary thyroid microcarcinomas (PTMC) has raised concerns for overdiagnosis. Utility of the American Thyroid Association Risk Stratification System (ATA-RSS) 2015 in predicting risk of disease recurrence in patients with PTMC was assessed.

METHODS

Electronic health records of patients who underwent total thyroidectomy were queried. ATA-RSS 2015 risk stratification was performed on those with PTMC, and validity for predicting disease recurrence was calculated.

RESULTS

With 10-year median follow up, recurrence was higher in PTMC patients with high/intermediate vs low ATA risk (33 ​% vs 4 ​%, p ​= ​0.002). Sensitivity of ATA-RSS for detecting recurrence was 60 ​%, specificity 90 ​%, PPV 33.3 ​%, NPV 96.6 ​%, and accuracy 88 ​%. When microscopic extrathyroidal extension (ETE) was excluded as an intermediate risk criterion, PPV improved to 50 ​% and accuracy improved to 92.5 ​% CONCLUSIONS: ATA-RSS 2015 predicts recurrence in PTMC with high NPV but low PPV. Exclusion of microscopic ETE improved PPV, which may help prevent overtreatment.

Subcentimetric Papillary Thyroid Carcinoma: Does the Diagnosis Kind Impact Prognosis?

INTRODUCTION

Subcentimetric papillary thyroid carcinoma (SPTC) (papillary thyroid carcinoma with less than 10 mm in size) usually presents an excellent prognosis, with few aggressive reported cases. Given the globally increased incidence of SPTC, physicians are struggling with the need to identify prognostic factors to stratify SPTC. The aim was to compare clinicopathological variables and prognosis between clinically and incidentally diagnosed SPTC. Materials and methodsː This is a retrospective observational study on patients with SPTC who underwent thyroidectomy between 2002 and 2015. Two groups were considered: G1 (n=60 (61.9%)), clinical diagnosis (Bethesda III-VI cytology in the thyroid tumor/in cervical lymphadenopathies) and G2 (n=37 (38.1%)), incidental diagnosis (thyroidectomy for benign thyroid pathology). The histological material was reviewed, and molecular analysis of the BRAF, RAS, and TERT promoter (TERTp) genes was performed. Resultsː Ninety-seven individuals were included, 60 (61.9%) of which were from G1, with a predominance of female sex (n=83 (85.6%)). Individuals of G1 were younger (53.0±14.2 versus 59.3±13.9 years; p=0.035), were more frequently treated with 131-iodine (39.2% versus 13.4%; p=0.007), had the largest diameter (8 (p25-p75: 7-9) versus 5 (p25-p75: 4-6.5) mm; p<0.001), and higher frequency of minimal extracapsular invasion (45% versus 24.3%; p=0.041). Increased tumor size was the only independent predictor of a clinical diagnosis (p<0.001). Conclusionsː Clinically and incidentally diagnosed SPTC showed excellent medium- to long-term prognosis. A larger SPTC was more likely a driver of clinical detection than a marker of tumor aggressiveness, but caution should be taken as contradictory data persists.

Factors influencing extrathyroidal extension of papillary thyroid cancer and evaluation of ultrasonography for its diagnosis: a retrospective analysis

Pathologists usually explore extrathyroidal extensions (ETEs) in thyroid cancer; however, sonographers are often not concerned with ETEs. We investigated factors influencing ETEs and the efficacy of ultrasound evaluation of thyroid capsule invasion. We retrospectively analysed 1933 papillary thyroid carcinoma patients who underwent thyroidectomy during 2018-2021. Patients were divided into three groups: no ETE, minor ETE (mETE), and gross ETE. Clinical characteristic differences were assessed using binary logistic regression analysis to identify ETE predictors, and the kappa test was performed to analyse consistency between ultrasonographic and pathological diagnoses of ETE. The mETE group was more likely to have larger tumour diameters and more extensive lymph node metastasis (LNM) than the no ETE group and more likely to be diagnosed in the isthmus. In the multivariate logistic regression analysis, longest tumour diameter, lesion site, LNM extent, and thyroglobulin concentration were significant mETE predictors. Minimal consistency existed between pathological and ultrasonographic examinations for neighbouring tissue invasion. Many clinical differences were observed between the no ETE and mETE groups, suggesting the importance of considering mETE. Therefore, sonographers should pay more attention to relationships between nodules and capsule and indicate these on ultrasound reports to provide more accurate preoperative ETE information for surgeons.

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.

Causal inference between aggressive extrathyroidal extension and survival in papillary thyroid cancer: a propensity score matching and weighting analysis

Background

Extrathyroidal extension is a major risk factor for poor prognosis in papillary thyroid cancer. However, the effect of different degrees of extrathyroidal extension on prognosis remains controversial. We performed a retrospective study to elucidate how the extent of extrathyroidal extension in papillary thyroid cancer affected the clinical prognosis of patients and its covariates.

Methods

The study included 108,426 patients with papillary thyroid cancer. We categorized the extent of extension into none, capsule, strap muscles, and other organs. Three causal inference methods for retrospective studies, namely, inverse probability of treatment weighting, standardized mortality ratio weighting, and propensity score matching analysis, were used to minimize potential selection bias. Kaplan-Meier analysis and univariate Cox regression analyses were applied to analyze the precise effect of ETE on survival in papillary thyroid cancer patients.

Results

In the Kaplan-Meier survival analysis, only extrathyroidal extension into or beyond the strap muscles was statistically significant for both overall survival (OS) and thyroid cancer-specific survival (TCSS). In univariate Cox regression analyses before and after matching or weighting based on causal inference, extrathyroidal extension into soft tissues or other organs is a high-risk factor for both overall survival and thyroid cancer-specific survival. Sensitivity analysis revealed that lower overall survival was observed in patients with older age (≥55) and larger tumor size (>2 cm) of papillary thyroid cancer with extrathyroidal extension into or beyond the strap muscles.

Conclusions

Our study indicates that extrathyroidal extension into soft tissues or other organs is a high-risk factor in all papillary thyroid cancer. Even though invasion into the strap muscles did not seem to be a marker for poor prognosis, it still impaired the overall survival of patients with older age (≥55 years old) or larger tumor size (>2 cm). Further investigation is needed to confirm our results and to clarify further risk factors independent of extrathyroidal extension.

The Diagnostic Performance of Ultrasonography in the Evaluation of Extrathyroidal Extension in Papillary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Extrathyroidal extension (ETE) in patients with papillary thyroid carcinoma (PTC) is an indication of disease progression and can influence treatment aggressiveness. This meta-analysis assesses the diagnostic accuracy of ultrasonography (US) in detecting ETE. A systematic review and meta-analysis were performed by searching PubMed, Embase, and Cochrane for studies published up to April 2022. The pooled sensitivity, specificity, and diagnostic odds ratio (DOR) were calculated. The areas under the curve (AUC) for summary receiver operating curves were compared. A total of 11 studies analyzed ETE in 3795 patients with PTC. The sensitivity of ETE detection was 76% (95%CI = 74-78%). The specificity of ETE detection was 51% (95%CI = 49-54%). The DOR of detecting ETE by US was 5.32 (95%CI = 2.54-11.14). The AUC of ETE detection was determined to be 0.6874 ± 0.0841. We report an up-to-date analysis elucidating the diagnostic accuracy of ETE detection by US. Our work suggests the diagnostic accuracy of US in detecting ETE is adequate. Considering the importance of ETE detection on preoperative assessment, ancillary studies such as adjunct imaging studies and genetic testing should be considered.

Clinical Significance of Tumor Size in Gross Extrathyroidal Extension to Strap Muscles (T3b) in Papillary Thyroid Carcinoma: Comparison with T2

The purpose of the present study was to compare the risk of recurrence between T2 and T3b papillary thyroid carcinoma (PTC) and the effect of tumor size on survival in T3b disease. A total of 634 patients with PTC who underwent thyroid surgery at a single center were retrospectively analyzed. Clinicopathological characteristics were compared according to the T category in the TNM staging system, with T3b divided into T3b-1 (tumor size, ≤2 cm) and T3b-2 (tumor size, 2–4 cm). Disease-free survival (DFS) and recurrence risk were compared between T2, T3b, T3b-1, and T3b-2. Tumor size was significantly larger in T2 than in T3b. A significant difference in recurrence was observed between T2 and T3b-2 but not between T2 and T3b-1. T3b-2 was identified as a significant risk factor for PTC recurrence. A significant difference in the DFS curve was observed between T2 and T3b-2. However, no significant differences in survival were observed between T2 and T3b or T3b-1. These results indicate that the prognostic impact of T3b may vary depending on tumor size. Further studies are required to determine the need for T classifications that account for tumor size and gETE invasion of the strap muscles.

Preoperative Ultrasonography in the Evaluation of Suspected Familial Non-Medullary Thyroid Cancer: Are We Able to Predict Multifocality and Extrathyroidal Extension?

Family history of thyroid cancer increases the risk of harboring thyroid malignancies that end up having extrathyroidal extension (ETE) and multifocality on histology; some authors suggest a more aggressive surgical approach. Their pre-operative identification could allow more conservative surgical procedures if none of these features are suspected. Our aim was to assess if neck ultrasonography could identify or exclude multifocality or ETE in these patients to tailor the extent of surgery. This retrospective study included patients with previous thyroid surgery, ≥1 first-grade relative with thyroid cancer, and who had undergone pre-surgical ultrasound. ETE was suspected in the case of thyroid border interruption or gross invasion of perithyroidal tissues. Multiple suspicious nodules were defined as suspicion of multifocal cancer. The cohort consisted of 45 patients (median age 49 years, 40 with thyroid cancer, 30 females). The positive predictive value of ultrasonography in predicting multifocality and ETE was 57.14% (25.25–84.03) and 41.67% (21.5–65.1%), respectively, while the negative predictive values were 63.2% (56.4–69.4%) and 72.7% (63.3–80.5%). Pre-operative ultrasound examination is unable to reliably identify or exclude multifocal disease or extrathyroidal extension. In patients scheduled for surgery and with a first-degree relative affected by DTC, a “negative” pre-operative US report does not exclude the potential finding of multifocality and ETE at final histopathology.

A predictive model and survival analysis for local recurrence in differentiated thyroid carcinoma

BACKGROUND

Local recurrence (LR) is associated with poor outcome in patients with differentiated thyroid carcinoma (DTC). The aim of this study was to explore potential risk factors for LR and build a predictive model.

METHODS

The medical data of patients who were diagnosed with DTC after initial surgery in three medical centers (2000-2018) were reviewed. Detailed clinicopathologic characteristics of all cases were identified.

RESULTS

Multiple factors, including extrathyroidal extension (ETE), histology, symptoms, multifocality, and tumor diameter, were significantly different between the LR and no evidence of disease groups in univariate and multivariate analysis (P ˂ 0.05). Tumor diameter, symptoms, and ETE made the greatest contributions to prognosis according to decision tree analysis and random forest algorithm. The predictive model constructed from these data achieved 98.7% accuracy of classification. A five-fold cross-validation confirmed that the model has 84.7%-89.7% accuracy of classification. Additionally, symptoms and ETE were independent predictors on survival analysis (P ˂ 0.05).

CONCLUSIONS

This study optimized the weight of risk factors, including tumor diameter, symptoms, ETE, and multifocality, in predicting LR in patients with DTC. Our predictive model provides a strong tool to distinguish between high-risk and low-risk DTC.

Unnecessity of Routine Dissection of Right Central Lymph Nodes in cN0 Papillary Thyroid Carcinoma Located at the Left Thyroid Lobe

Objective

The lymph node posterior to the right recurrent laryngeal nerve (LN-prRLN) is an important part of the central lymph nodes (LNs). We aimed to explore the rate and predictors of LN-prRLN metastasis in cN0 papillary thyroid carcinoma (PTC) located at the left thyroid lobe.

Methods

Patients with surgically treated primary left lobe PTC were retrospectively enrolled. The metastatic distribution of LN-prRLN and postoperative complications were assessed. The association between LN-prRLN metastasis and clinicopathological variables was evaluated by univariate and multivariate analyses.

Results

A total of 857 patients were included for the analysis. Central LN metastasis was noted in 310 (35.3%) cases. The most (27.6%) and least (1.7%) commonly involved LNs were the left paratracheal LN and the LN-prRLN. In the univariate analysis, the tumor size, multifocality, the extent of extrathyroidal extension (none vs. macroscopic vs. macroscopic maximal), and perineural invasion were associated with positive LN-prRLN. In the multivariate analysis, tumor size of >40.0 mm and macroscopic maximal invasion were found as the only two independent predictors. Transient and permanent hypoparathyroidism were noted in 90 (10.2%) and 13 (1.5%) patients, respectively. Voice change was noted in 40 (4.6%) patients, and 20 patients recovered.

Conclusions

In cN0 PTC located at the left lobe, LN-prRLN metastasis was very uncommon. We found that LN-prRLN dissection is not required routinely, but should be performed if the tumor size is >40.0 mm and macroscopic maximal extrathyroidal extension is present.

Can Diffusion-Weighted MR Imaging Be Used as a Tool to Predict Extrathyroidal Extension in Papillary Thyroid Carcinoma?

RATIONALE AND OBJECTIVES

To evaluate whether quantitative diffusion-weighted MR imaging (DWI) with multi-b values can be used as a tool to predict the aggressiveness by using the histological feature of extrathyroidal extension (ETE) in papillary thyroid carcinoma (PTC).

MATERIALS AND METHODS

238 patients were pathologically confirmed as PTCs underwent preoperative multi-b value DWI (300, 500, and 800 s/mm²) between January 2015 and December 2017. The patients were divided into three groups according to the degree of ETE: without ETE, minimal ETE, and extensive ETE. The apparent diffusion coefficients (ADCs) were evaluated for three different b values (b = 300 s/mm², b = 500 s/mm², and b = 800 s/mm²). The ADC values of the groups with and without ETE, minimal and extensive ETE were compared. The diagnostic relevance of the ADC values in terms of predicting ETE was compared using a receiver operating characteristic analysis. Differences between the areas under the curves (AUCs) were compared by using a Delong test.

RESULTS

PTCs with ETE had significantly lower ADC₃₀₀, ADC₅₀₀ and ADC₈₀₀ values than PTCs without ETE (p = 0.001, p < 0.001, and p < 0.001, respectively). The AUC of the mean ADC₅₀₀ value (0.905) was higher than that of the ADC₃₀₀ and ADC₈₀₀ values (0.607 and 0.770, respectively) in differentiating ETE from without ETE (p < 0.001). The cut-off value of ADC₅₀₀ to discriminate PTCs with and without ETE was determined at 1.407 × 10^-3 mm²/s, with sensitivity of 80.7%, specificity of 86.7%, and an AUC of 0.905.

CONCLUSION

The ADC value can be demonstrated an effective tool for evaluating the aggressiveness with the histological feature of ETE in PTC. In particular, ADC value at b = 500 s/mm² showed the best performance for noninvasive preoperative evaluation of ETE.

Lymph node metastasis in the space between the right carotid artery and jugular vein in papillary thyroid carcinoma

Background

The oblique brachiocephalic trunk and right common carotid artery constitute the right carotid sheath space (RCSS). The aim of this study was to detect the clinicopathologic factors associated with RCSS lymph node metastasis.

Methods

In total, 232 papillary thyroid carcinoma (PTC) patients with preoperative contrast-enhanced computed tomography scans were analyzed for associations between RCSS lymph node metastasis and clinicopathological factors.

Results

Among the 232 cases, 18 (7.76%) had suspicious RCSS lymph nodes, which was correlated with the presence of >5 metastatic lymph nodes, a larger thoracic inlet, and primary tumor size >2.15 cm. All pathologically confirmed metastatic lymph nodes were >1 cm in diameter.

Conclusions

The concept of “RCSS lymph node metastasis” was first introduced by this study. For PTC patients, a larger thoracic inlet, increased number of metastatic lymph nodes, and larger primary tumor size were related to RCSS lymph nodes, and more attention should be paid to patients who have lymph nodes >1 cm. A future prospective study will be designed to identify the potential risk factors for RCSS lymph node metastasis.

Risk Factors and Prediction Model for Lateral Lymph Node Metastasis of Papillary Thyroid Carcinoma in Children and Adolescents

Purpose

Papillary thyroid carcinoma (PTC) in children and adolescents is prone to lateral lymph node metastasis (LNM), which is a high-risk factor for recurrence. However, few studies focused on identifying risk factors and establishing prediction models for lateral LNM of PTC in children and adolescents.

Patients and Methods

We retrospectively reviewed consecutive cases of children and adolescents with PTC undergoing thyroidectomy and cervical lymph node dissection between January 2009 and December 2019. The demographics and clinicopathologic features were collected and analyzed.

Results

A total of 102 children and adolescents with PTC were enrolled in our study; 51 of whom had lateral LNM (50%). After adjusting for other risk factors, the independent risk factors for lateral LNM were multifocality (odds ratio [OR]: 6.04; 95% confidence interval [CI]: 1.653–22.092; p=0.007), tumor size (OR: 1.752; 95% CI: 1.043–2.945; p=0.034), and the number of central LNM (OR: 1.23; 95% CI: 1.028–1.472; p=0.023). The formula of the combined predictor is: Multifocality + 0.31 × Tumor size + 0.115 × Number of central LNM. The area under the receiver operating characteristic curve of multifocality, tumor size, number of central LNM, and the combined predictor was 0.706, 0.762, 0.748, and 0.855, respectively. When the value of the combined predictor was ≥2.2744, lateral LNM could be predicted. The sensitivity and specificity of the predicted value were 82.4% and 74.5%, respectively.

Conclusion

The independent risk factors for lateral LNM in children and adolescents with PTC were multifocality, tumor size, and the number of central LNM. The prediction model can better predict the presence of lateral LNM.

Total tumor diameter: the neglected value in papillary thyroid microcarcinoma

BACKGROUND

Tumor multifocality is not uncommon in papillary thyroid carcinoma (PTC), especially in micro-PTC. However, assessing the size of the largest tumor may underestimate effect of additional foci. We aimed to investigate the effect of total tumor diameter (TTD) on clinicopathological features of micro-PTC.

METHODS

Data from 442 patients who underwent thyroidectomy with cervical lymph node dissection for PTC were retrospectively analyzed. Patients were classified into subgroups according to multifocality and TTD. The relationships of clinicopathological features among these groups were analyzed.

RESULTS

Multifocality was observed in 119 patients (26.9%). TTD > 1 cm and presence of extrathyroidal extension (ETE) were significantly higher in multifocal tumors compared to unifocal tumor (P < 0.001, P = 0.016, respectively). When comparing multifocal micro-PTC with TTD > 1 cm to those with unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm, the proportions of cases with ETE, central lymph node metastasis (CLNM), and lateral lymph node metastasis (LLNM) were significantly higher (all P < 0.05). There was no significant difference in terms of these parameters between multifocal micro-PTC with TTD > 1 cm and macro-PTC or multifocal macro-PTC. The risk of CLNM was 2.056 (P = 0.044) times higher in multifocal micro-PTC with TTD > 1 cm than in unifocal micro-PTC.

CONCLUSION

For multifocal micro-PTC, TTD can better assess the aggressiveness of the tumor. Multifocal micro-PTC with TTD > 1 cm was more aggressive than unifocal micro-PTC or multifocal micro-PTC with TTD ≤ 1 cm.

Invasion in thyroid cancer: Controversies and best practices

Invasion is a key feature of malignancy and an important element in the classification, risk-stratification, and staging of thyroid cancers. However, the histopathologic criteria for tumor capsular invasion, angioinvasion, and extrathyroidal extension (ETE) have varied among pathologists, both in practice as well as in studies assessing the clinical significance of these findings. In this review, we provide historic context for the controversies surrounding the definition of invasion in thyroid neoplasms and highlight recent efforts to standardize how pathologists report capsular invasion, angioinvasion, and ETE. We offer practical suggestions for distinguishing invasion from its mimics and provide an algorithmic approach for classifying thyroid tumors based on integration of tumor invasiveness, nuclear atypia, and architectural pattern.

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.

Risk factors for posttreatment recurrence in patients with intermediate-risk papillary thyroid carcinoma

BACKGROUND

Papillary thyroid carcinoma (PTC) is generally associated with favorable outcomes; however, intermediate-risk requires further evaluation. We therefore examined risk factors for posttreatment recurrence in patients with intermediate-risk PTC.

METHODS

This study involved 1782 patients who underwent thyroidectomy for intermediate-risk PTC. Univariate and multivariate Cox proportional hazard regression analyses were used to identify the significant factors predictive of posttreatment recurrence-free survival (RFS).

RESULTS

Of intermediate-risk factors, univariate analyses showed that clinical and pathological cervical lymph node (LN) positivity (cN1 and pN1), aggressive histology, and multifocality with microscopic extrathyroidal extension were significantly associated with RFS outcomes (all P < 0.05). In multivariate analyses, cN1, >5 pN1, and posttreatment radioactive iodine (RAI)-avid metastatic foci of intermediate risk remained the independent factors predictive of RFS (all P < 0.05). The combination of any three or more of these intermediate-risk factors appeared to increase the posttreatment recurrence rate.

CONCLUSION

Clinical nodal positivity, the number of positive LNs, and the presence of RAI-avid metastatic foci in the ATA intermediate-risk category might independently decrease RFS in patients with intermediate-risk PTC.