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

The Role of 5-Hydroxymethylcytosine as a Potential Epigenetic Biomarker in a Large Series of Thyroid Neoplasms

Cytosine modifications at the 5-carbon position play a critical role in gene expression regulation and have been implicated in cancer development. 5-Hydroxymethylcytosine (5hmC), arising from 5-methylcytosine (5-mC) oxidation, has shown promise as a potential malignancy marker due to its depletion in various human cancers. However, its significance in thyroid tumors remains underexplored, primarily due to limited data. In our study, we evaluated 5hmC expression levels by immunohistochemistry in a cohort of 318 thyroid tumors. Our analysis revealed significant correlations between 5hmC staining extension scores and nodule size, vascular invasion, and oncocytic morphology. Nuclear 5hmC staining intensity demonstrated associations with focality, capsule status, extrathyroidal extension, vascular invasion, and oncocytic morphology. Follicular/oncocytic adenomas exhibited higher 5hmC expression than uncertain malignant potential (UMP) or noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP), as well as malignant neoplasms, including papillary thyroid carcinomas (PTCs), oncocytic carcinomas (OCAs), follicular thyroid carcinomas (FTCs), and invasive encapsulated follicular variants of PTC (IEFV-PTC). TERT promoter mutation cases showed notably lower values for the 5hmC expression, while RAS (H, N, or K) mutations, particularly HRAS mutations, were associated with higher 5hmC expression. Additionally, we identified, for the first time, a significant link between 5hmC expression and oncocytic morphology. However, despite the merits of these discoveries, we acknowledge that 5hmC currently cannot segregate minimally invasive from widely invasive tumors, although 5hmC levels were lower in wi-FPTCs. Further research is needed to explore the potential clinical implications of 5hmC in thyroid tumors.

Bilaterality as a Risk Factor for Recurrence in Papillary Thyroid Carcinoma

Previous studies suggested that the multifocality of papillary thyroid carcinoma (PTC) would increase the risk of recurrence; however, the impact of its bilaterality remains unclear. Between 2011 and 2018, 1258 patients with PTC underwent total thyroidectomy at Ewha University Medical Center. The 5-year recurrence-free survival rate was 95.7% in patients with bilateral PTC, while those with unilateral multifocal PTC and a unifocal tumor showed a 5-year event-free survival rate of 97.0% and 97.8%, respectively (p = 0.004). A multivariable Cox proportional hazards model indicated that bilaterality (HR 2.550, 95% CI 1.354-4.800), male sex (HR 2.010, 95% CI 1.007-4.013), and tumor size (HR 1.748, 95% CI 1.316-2.323) were associated with recurrence, although unilateral multifocality did not increase the risk of recurrence (HR 1.211, 95% CI 0.348-4.213). In conclusion, bilaterality was associated with aggressive features, including tumor size and microscopic ETE. Moreover, bilaterality was an independent predictor of recurrence in patients with PTC. Patients with bilateral PTC might require careful treatment and follow-up approaches.

The value of total tumor diameter in unilateral multifocal papillary thyroid carcinoma: a propensity score matching analysis

Background

Tumor multifocality is frequently observed in papillary thyroid carcinoma (PTC). However, the maximum tumor diameter (MTD), currently utilized in various staging schemes, might not accurately indicate the level of aggressiveness exhibited by multifocal tumors. We aimed to investigate the relationship between total tumor diameter (TTD) and clinicopathological features of papillary thyroid carcinoma.

Methods

Retrospective data analysis was done on 1936 individuals who underwent complete thyroidectomy for PTC. Patients were classified into subgroups according to unilateral multifocality, central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM). The relationships of clinicopathological features among these groups were analyzed.

Results

Unilateral multifocality was observed in 117 patients. The clinicopathological features of the unilateral multifocal PTC were similar to the unifocal PTC with approximate TTD. The unilateral multifocality played no independent role in CLNM and LLNM. Moreover, the efficiency of TTD in predicting CLNM and LLNM was significantly higher than that of MTD.

Conclusion

In the case of unilateral multifocal PTC, TTD is a more accurate indicator of the biological characteristics of the tumor than MTD.

Clinical Implication of Bilateral and Unilateral Multifocality in Papillary Thyroid Carcinoma: A Propensity Score-Matched Study

Papillary thyroid cancer (PTC) is commonly characterized by multifocality, which is associated with aggressive features and a less favorable prognosis. The current study aimed to compare the clinicopathologic characteristics and long-term oncological outcomes of bilateral and unilateral multifocal PTC. The medical records of 1745 patients with multifocal PTC who underwent thyroid surgery at Seoul St. Mary's Hospital were retrospectively reviewed. The clinicopathological characteristics and recurrence rates were compared based on cancer laterality. Further, 357 patients who underwent total thyroidectomy were matched to investigate the recurrence risk and disease-free survival (DFS). Before propensity score matching (PSM), there was no significant difference in the recurrence rate between the bilateral and unilateral multifocal PTC groups. Cancer laterality was not a predictor of DFS based on the Cox regression analyses. However, after PSM, unilateral multifocality was associated with a significantly high risk of recurrence. Similarly, unilateral multifocality was associated with a significantly poor DFS based on the Kaplan-Meier analysis. Compared with bilateral PTC, unilateral multifocal PTC was associated with a poor DFS. A comprehensive preoperative examination should be performed to detect multifocality before the initial surgical intervention for optimal treatment. Postoperative short-term follow-up is recommended for unilateral multifocal PTC for recurrence surveillance.

Should multifocality be an indication for prophylactic central neck dissection in papillary thyroid cancer?

Although multifocality is common in patients with papillary thyroid cancer, its effects on lymphatic metastasis and the necessity of central dissection in the presence of multifocality are still controversial. In our clinic, 258 patients who underwent thyroidectomy between 2015 and 2020 and were found to have papillary thyroid cancer in postoperative pathology reports were analyzed. The tumor characteristics contributing to central lymph node metastasis positivity were evaluated. Lymph node metastases were not significantly increased in the presence of multifocality. In cases with bilateral multifocal tumors, compared to cases with unilateral multifocal tumors, capsular invasion (p = 0.02), vascular invasion (p = 0.01) and cervical lymphatic metastasis (p = 0.004) were observed to increase. Bilateral multifocal tumors have more aggressive clinicopathological features than unilateral tumors. We found that the risk of central lymph node metastasis increased significantly in bilateral multifocal tumors in our study. Prophylactic central lymph node dissection may be considered in patients with no preoperative or intraoperative lymph node metastasis but thought to have a multifocal tumor.

Bilateral multifocality is an independent predictor of patients' outcome in Middle Eastern papillary thyroid carcinoma

Background

Tumor multifocality is frequently seen in Papillary thyroid carcinoma (PTC). However, few studies have analysed the impact of bilateral multifocality in PTC. The incidence of bilateral multifocality, its clinico-pathological associations and prognostic impact in PTC from Middle Eastern ethnicity remains unestablished.

Methods

We retrospectively evaluated 1283 patients who underwent total thyroidectomy for PTC. Bilateral and unilateral multifocality were decided based on the final pathology result. Primary outcome was recurrence free survival (RFS). Risk factors for bilateral multifocality were analyzed by multivariate logistic regression analysis.

Results

Multifocal PTC was found in 54.3% (697/1283) of patients. Among the 697 multifocal PTCs, 210 patients (30.1%) had unilateral multifocal PTC and 487 patients (69.9%) had bilateral multifocality. Bilateral multifocality was significantly associated with older age at diagnosis (p = 0.0263), male gender (p = 0.0201), gross extrathyroidal extension (p = 0.0332), larger primary tumor size (>4cm; p = 0.0002), lateral lymph node metastasis (p = 0.0008), distant metastasis at diagnosis (p = 0.0195) and recurrence (p = 0.0001). Bilateral multifocality was also found to be an independent predictor of RFS (Hazard ratio = 1.60; 95% Confidence Interval = 1.05 - 2.55; p = 0.0300). Multivariate logistic regression analysis demonstrated tumor diameter >4cm to be the only independent risk factors for bilaterality in multifocal PTC (Odds ratio = 1.86; 95% Confidence Interval = 1.13 - 3.07; p = 0.0155).

Conclusions

Incidence of bilateral multifocality is high in Middle Eastern PTC. Tumor diameter >4cm can be considered as a predictive factor for bilateral multifocal PTC. Bilateral multifocality appears to be an important prognostic factor for PTC and an independent predictor of RFS. Therefore, patients with bilateral multifocal PTC may benefit from more frequent follow-up to identify recurrences earlier.

Risk factors of cervical lymph node metastasis in multifocal papillary thyroid cancer

Introduction

Identifying risk variables for cervical lymph node metastases in multifocality papillary thyroid cancer (MPTC) could assist surgeons in determining whether cervical lymph node dissection would be an appropriate surgical option.

Methods

A retrospective cohort of 2006 patients with papillary thyroid cancer were selected. MPTC (N = 460) was defined as the presence of two or more foci of PTC. The risk factors for central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) in MPTC were investigated by univariate and multivariate analyses, including the following items: age at diagnosis, gender, Hashimoto's thyroiditis, extrathyroidal extension (ETE), maximal axial diameter (MAD) and the sum of axial diameters (SAD) of tumor. In addition, CLNM was used to evaluate LLNM.

Results

The incidence of CLNM and LLNM was 44.57% and 17.17%, respectively. The multivariate analysis demonstrated that gender, extrathyroidal extension (ETE), age, maximal axial diameter (MAD), and the sum of axial diameters (SAD) were related to increased risk for CLNM in MPTC (p < 0.05). The area under the receiver operating characteristic (ROC) curve (AUC) for age at diagnosis of CLNM was 0.647, the cut-off value was 50 years old. Additionally, by multivariate analysis, CLNM, ETE, MAD, and SAD were independent risk factors for LLNM in MPTC (p < 0.05). ROC curve analysis demonstrates that AUC for MAD and SAD diagnosis of LLNM were 0.639 and 0.757, and the cut-off values were 16 and 26 mm, respectively.

Conclusions

MPTC patients who have risk factors for CLNM were advised to perform prophylactic central lymph node dissection (CLND). Additionally, the presence of risk factors for LLNM should be individually evaluated and analyzed for the necessity of lateral lymph node dissection.

ERBB2 as a prognostic biomarker correlates with immune infiltrates in papillary thyroid cancer

Epidermal growth factor receptor 2 (ERBB2) is commonly over-expressed in advanced or metastatic tissues of papillary thyroid cancer (PTC) with poor prognosis, while it remains unknown whether ERBB2 plays a role in the progression of PTC. Thus, we analyzed the data derived from online repositories, including TCGA, KEGG, GO, GeneMANIA, and STRING, to explore the relationship between ERBB2 expression and prognosis, tumor phenotypes of interest, and immune infiltrates in PTC. Compared to normal thyroid tissue, ERBB2 was up-regulated in PTC samples (p < 0.001); In comparison with the group with low expression of ERBB2, the group with high expression of ERBB2 had poorer progression-free interval in stage III/IV patients (p = 0.008) and patients aged >45 years (p = 0.019). The up-regulated ERBB2 was associated with iodine metabolism dysfunction, proliferation, metastasis, angiogenesis, and drug resistance. The expression of ERBB2 negatively correlated with enrichment scores of B cells (r = −0.176, p < 0.001), CD8⁺ T cells (r = −0.160, p < 0.001), cytotoxic cells (r = −0.219, p < 0.001), NK CD56dim cells (r = −0.218, p < 0.001), plasmacytoid dendritic cells (r = −0.267, p < 0.001), T cells (r = −0.164, p < 0.001), T follicular helper cells (r = −0.111, p = 0.012), gamma delta T cells (r = −0.105, p = 0.017), and regulatory T cells (r = −0.125, p = 0.005). In conclusion, ERBB2 may serve as a prognostic biomarker and an immunotherapeutic target in PTC, deserving further exploration.

Number of Tumor Foci as a Risk Factor for Recurrence in Papillary Thyroid Carcinoma: Does It Improve Predictability?

Multifocality in papillary thyroid carcinoma (PTC) increases the risk of recurrence. Some recent studies have suggested that multifocality-related parameters, such as the number of tumor foci, total tumor diameter (TTD), and bilaterality, are more useful for predicting recurrence than multifocality. However, it is still unclear if these factors can improve the accuracy of the recurrence prediction model. Between 2012 and 2019, 1288 patients with PTC underwent total thyroidectomy at Ewha Womans University Medical Center. The 5-year disease-free survival rate was 91.2% in patients with >3 tumor foci, 95.1% with 3 foci, and 97.6% with 2 foci; conversely, those with a unifocal tumor showed a 5-year recurrence-free survival rate of 98.0%. Cox proportional hazards analysis indicated that the number of tumor foci (HR for >3 foci, 3.214; HR for 3 foci, 2.473), bilaterality (HR, 2.530), or TTD (HR for >3 cm, 5.359; HR for 2−3 cm, 3.584) could be an independent predictor of recurrence. However, models using the number of tumor foci, bilaterality, and TTD did not show better overall predictability of recurrence than models based on multifocality. In conclusion, a simpler prediction model based on multifocality may be sufficient.

Clinical outcomes of multifocal papillary thyroid cancer: A systematic review and meta-analysis

Objective

Papillary thyroid cancer (PTC) is the most common endocrine malignancy with a steadily increasing incidence. Researches have reported that tumor multifocality occurs in an extensive number of cases. Nevertheless, the clinical characteristics and prognostic value remained controversial. This study was performed to investigate the relationship between multifocal PTC and adverse clinicopathologic features and the prognosis.

Methods

A systematic review and meta-analysis were conducted based on three electronic databases up to December 31, 2021. Parameters of interest included five clinical features (extrathyroidal extension, lymphovascular invasion, central lymph node metastasis, lateral lymph node metastasis, distant metastasis) and were pooled into risk ratios (RRs). Time-to-event data (recurrence-free survival and all-cause mortality) were evaluated using hazard ratios (HRs). Publication bias was examined using funnel plots and Egger's test.

Results

A total of 23 articles were included according to the inclusion criteria; all of the studies were retrospective cohorts. In comparison with unifocality, multifocality showed an increased risk of extrathyroidal extension (RR 1.38, 95% CI 1.25-1.53), lymphovascular invasion (RR 1.27, 95% CI 1.04-1.55), central lymph node metastasis (RR 1.21, 95% CI 1.12-1.30), lateral lymph node metastasis (RR 1.86, 95% CI 1.62-2.14), and distant metastasis (RR 1.35, 95% CI 1.03-1.76). Multifocal patients were predisposed to postoperative recurrence (HR 1.76, 95% CI 1.50-2.07). The rate of all-cause mortality did not reach a statistical difference.

Level of Evidence

2.

Conclusion

Multifocal PTC is more aggressive in contrast to unifocal PTC and is accompanied by an increased risk of recurrence. They were usually diagnosed in higher grades and stages. To achieve the maximal benefit, we recommend personalized therapy and close follow-up for multifocal PTC patients. Further prospective studies will clarify the best-fitted treatment plans.

Real-Time Elastography: A Web-Based Nomogram Improves the Preoperative Prediction of Central Lymph Node Metastasis in cN0 PTC

BACKGROUND

Given the difficulty of accurately determining the central lymph node metastasis (CLNM) status of patients with clinically node-negative (cN0) papillary thyroid carcinoma (PTC) before surgery, this study aims to combine real-time elastography (RTE) and conventional ultrasound (US) features with clinical features. The information is combined to construct and verify the nomogram to foresee the risk of CLNM in patients with cN0 PTC and to develop a network-based nomogram.

METHODS

From January 2018 to February 2020, 1,157 consecutive cases of cN0 PTC after thyroidectomy and central compartment neck dissection were retrospectively analyzed. The patients were indiscriminately allocated (2:1) to a training cohort (771 patients) and validation cohort (386 patients). Multivariate logistic regression analysis of US characteristics and clinical information in the training cohort was performed to screen for CLNM risk predictors. RTE data were included to construct prediction model 1 but were excluded when constructing model 2. DeLong's test was used to select a forecast model with better receiver operator characteristic curve performance to establish a web-based nomogram. The clinical applicability, discrimination, and calibration of the preferable prediction model were assessed.

RESULTS

Multivariate regression analysis showed that age, sex, tumor size, bilateral tumors, the number of tumor contacting surfaces, chronic lymphocytic thyroiditis, and RTE were risk predictors of CLNM in cN0 PTC patients, which constituted prediction model 1. Model 2 included the first six risk predictors. Comparison of the areas under the curves of the two models showed that model 1 had better prediction performance (training set 0.798 vs. 0.733, validation set 0.792 vs. 0.715, p < 0.001) and good discrimination and calibration. RTE contributed significantly to the performance of the prediction model. Decision curve analysis showed that patients could obtain good net benefits with the application of model 1.

CONCLUSION

A noninvasive web-based nomogram combining US characteristics and clinical risk factors was developed in the research. RTE could improve the prediction accuracy of the model. The dynamic nomogram has good performance in predicting the probability of CLNM in cN0 PTC patients.

Prevalence and Risk Factors for Multifocality in Pediatric Thyroid Cancer

Importance

Current guidelines recommend total thyroidectomy for the majority of pediatric thyroid cancer owing to an increased prevalence of multifocality. However, there is a paucity of information on the exact prevalence and risk factors for multifocal disease-knowledge that is critical to improving pediatric thyroid cancer management and outcomes.

Objective

To determine the prevalence and risk factors for multifocal disease in pediatric patients with papillary thyroid carcinoma (PTC).

Design, Setting, and Participants

This multicenter retrospective cohort study included patients 18 years or younger who underwent thyroidectomy for PTC from 2010 to 2020 at 3 tertiary pediatric hospitals and 2 tertiary adult and pediatric hospitals in the US.

Main Outcomes and Measures

Demographic and clinical variables, including age, family history of thyroid cancer, autoimmune thyroiditis, prior radiation exposure, cancer predisposition syndrome, tumor size, tumor and nodal stage, PTC pathologic variant, and preoperative imaging, were assessed for association with presence of any multifocal, unilateral multifocal, and bilateral multifocal disease using multiple logistic regression analyses. Least absolute shrinkage and selection operator analysis was performed to develop a model of variables that may predict multifocal disease.

Results

Of 212 patients, the mean age was 14.1 years, with 23 patients 10 years or younger; 173 (82%) patients were female. Any multifocal disease was present in 98 (46%) patients, with bilateral multifocal disease in 73 (34%). Bilateral multifocal disease was more accurately predicted on preoperative imaging than unilateral multifocal disease (48 of 73 [66%] patients vs 9 of 25 [36%] patients). Being 10 years or younger, T3 tumor stage, and N1b nodal stage were identified as predictors for multifocal and bilateral multifocal disease.

Conclusions and Relevance

This large, multicenter cohort study demonstrated a high prevalence of multifocal disease in pediatric patients with PTC. Additionally, several potential predictors of multifocal disease, including age and advanced T and N stages, were identified. These risk factors and the high prevalence of multifocal disease should be considered when weighing the risks and benefits of surgical management options in pediatric patients with PTC.

The Differences Between Multifocal and Unifocal Papillary Thyroid Carcinoma in Unilateral Lobe: A Meta-Analysis

Background

As many inconsistent reports on the clinical manifestations and prognosis between unilateral unifocal PTC (UUPTC) and unilateral multifocal PTC (UMPTC), identifying the difference should guide management. The purpose of this study was to investigate other additional differences between UUPTC and UMPTC in addition to their difference in the number of cancer foci.

Data Sources

A systematic literature search was conducted in the PubMed and Web of Science databases for relevant studies published before December 31, 2020. Their reference lists were also reviewed.

Review Methods

Two reviewers independently extracted data and assessed the quality of eligible studies. Studies on patients who underwent an open thyroidectomy with or without neck dissection were included. Data were analyzed using the RevMan 5.3 software.

Results

Fifteen studies comprising 9,665 patients were selected for the meta-analysis. UMPTC occurred in 10% to 36% of all PTC cases. There were no significant differences between UMPTC and UUPTC patients in age, gender, tumor size, and extrathyroidal extension (ETE). However, significant differences (P < 0.05) between UMPTC and UUPTC patients were observed in central lymph node metastasis (CLNM), lateral lymph node metastasis (LLNM), tumor-node-metastasis (TNM) stage I+II, TNM stage III+IV, the recurrence/persistence of the UMPTC group after total thyroidectomy and overall recurrence/persistence.

Conclusion

UMPTC patients are more likely to have CLNM, LLNM, more advanced TNM stage, and recurrence/persistence than UUPTC patients. Compared with UUPTC, UMPTC patients should undergo central lymph node dissection, and pay more attention to LLNM, TNM stage and recurrence/persistence during the follow-up.

Clinical Study of Virtual Reality Augmented Technology Combined with Contrast-Enhanced Ultrasound in the Assessment of Thyroid Cancer

Thyroid cancer has become the most common malignant tumor in the endocrine system, and its global incidence has been showing an upward trend. The diagnosis methods of thyroid cancer include ultrasound, fine-needle aspiration cytology, and neck CT, but the single ultrasound feature cannot simultaneously take into account the sensitivity and specificity of more than 85% when diagnosing thyroid cancer. The development of virtual technology can significantly improve the diagnosis of the thyroid gland. Based on this, this article proposes a clinical study of virtual reality technology combined with contrast-enhanced ultrasound in the assessment of thyroid cancer. This article uses a variety of methods, such as literature method, mathematical statistics, and experimental research, in-depth study of the theoretical cornerstones of virtual reality augmented technology, the application status of ultrasound contrast technology, and so on. And a fuzzy mean clustering algorithm was proposed to identify ultrasound images. Then, a clinical experiment of virtual reality augmented technology combined with contrast-enhanced ultrasound was designed to evaluate thyroid cancer, which included comparison of contrast-enhanced ultrasound signs, analysis of enhancement results, multifactor logistic analysis, and diagnostic efficacy analysis of ultrasound signs. The combined application of virtual reality augmented technology and contrast-enhanced ultrasound in the study of thyroid cancer has a sensitivity and specificity exceeding 85% as the diagnosis boundary changes, and the accuracy of the combined diagnosis is relatively high.

Multifocality and Progression of Papillary Thyroid Microcarcinoma During Active Surveillance

BACKGROUND

Prospective trials of active surveillance (AS) have shown low rates of progression in low-risk papillary thyroid microcarcinoma (PTMC; T1aN0M0). However, the significance of multifocality as a prognostic factor remains controversial.

METHODS

Data from 571 patients (mean age, 53.1 years; 495 females) who underwent AS were reviewed. PTMC was unifocal in 457 patients (80.0%) and multifocal in 114 patients (20.0%), with 2-5 lesions each (261 tumors in total). Tumor progression was defined as tumor size enlargement ≥ 3 mm and/or development of clinically evident lymph node metastasis (LNM).

RESULTS

After a mean duration of AS of 7.6 years, 53 patients (9.3%) showed tumor enlargement and 8 patients (1.4%) developed LNM. The 10-year progression rate was 13.1%. Age, sex, and calcification pattern did not differ significantly between uni- and multifocal diseases. However, anti-thyroglobulin antibody and/or anti-thyroid peroxidase antibody was more frequently positive with multifocal PTMCs (46.7%) than with unifocal disease (34.4%, p = 0.024). Patients with uni- and multifocal disease showed no significant differences in 10-year rate of tumor enlargement (11.4% vs. 14.8%), LNM development (1.1% vs. 2.4%), or progression (12.4% vs 15.9%). Multivariate analysis of predictors for progression showed multifocality was not a significant risk factor (odds ratio, 1.45; 95% confidence interval, 0.79-2.54; p = 0.22). Eventually, 9 patients (7.9%) with multifocal PTMCs underwent surgery and 7 needed total thyroidectomy, although 7 still showed T1N0M0 low-risk cancer.

CONCLUSIONS

Even patients with multiple PTMCs (T1amN0M0) are good candidates for AS. Many patients can avoid total thyroidectomy and subsequent surgical complications.

Bilateral papillary thyroid cancer in children: Risk factors and frequency of postoperative diagnosis

BACKGROUND

The recommendation for children with papillary thyroid cancer (PTC) is total thyroidectomy (TT) based on the incidence of bilateral disease. Evaluating this assumption, we reviewed the characteristics of bilateral PTC in a large cohort of children.

METHODS

A retrospective chart review for patients surgically treated for PTC from 2009 to 2018 analyzing preoperative risk factors, ultrasound findings, and pathology results was performed. Bilateral disease was defined as pathologic PTC in the contralateral lobe, including microscopic disease.

RESULTS

Of the 172 patients included, 38.4% had bilateral disease with 23% diagnosed postoperatively. Multifocal disease on ultrasound was associated with bilateral disease (OR 2.9, 95% CI 1.5-5.9, p = 0.002). Nodule dimension >2 cm was associated with increased risk for postoperative bilateral disease (OR 3.5, 95% CI 1.6-7.4, p = 0.001). Patients with bilateral disease were more likely to have extrathyroidal extension, lymphovascular invasion, positive central lymph nodes, and extranodal extension (p < 0.001 for all). Diffuse-sclerosing variant PTC was also associated with bilateral disease.

CONCLUSION

Thirty-eight percent of children were diagnosed with PTC demonstrate bilateral disease. Nearly one in four have occult bilateral disease. The features that predicted bilateral disease were multifocality, widely invasive PTC on ultrasound, and the presence of lymphadenopathy. Thus, TT is the appropriate surgical approach for pediatric patients with PTC.

TYPE OF STUDY

Clinical Research, Retrospective Review.

LEVEL OF EVIDENCE

Level IV.

Prognostic significance of the sum of the diameters of single foci in multifocal papillary thyroid cancer: the concept of new-old tumor burden

AIM

The prognostic value of multifocality (Mu) in papillary thyroid cancer (PTC) remains controversial. The present study aimed to investigate this issue and test the possible prognostic significance of the sum of the diameters of single foci (SDSF), the total number of foci (TNF), and primary tumor size (PTS) in multifocal PTC.

METHODS

We retrospectively analyzed a single-center consecutive series of 370 PTCs. For multifocal cases we analyzed bilaterality occurrence, SDSF, TNF, and PTS.

RESULTS

Mu was observed in 41.1% PTCs, and bilaterality in 30%. Mu was associated with an advanced T-category. In bilateral multifocal PTC, the PTS was larger, and microPTC was less frequent, while T-categories were higher. Mu and bilaterality per se had no impact on prognosis. At univariate analysis, PTS, SDSF, vascular invasion, lymph node metastases, distant metastases, T-categories, Initial Risk Stratification System score, second treatment and TERT promoter mutation correlated with persistence/recurrence or death in the multifocal PTC group. On multivariate Cox proportional hazards regression analyses, SDSF again independently predicted persistence/recurrence or death in multifocal PTCs. We found that a cut-off for SDSF less than 40 mm was able to identify multifocal PTC patients with a very low risk of persistence/recurrence (negative predictive value 96.9%). Disease-free survival was significantly shorter in patients with multifocal PTCs and SDSF ⩾40 mm.

CONCLUSIONS

Mu and bilaterality per se were not prognostically significant. SDSF emerged as a new independent prognostic factor for persistence/recurrence of multifocal PTC. SDSF might better represent the tumor burden in multifocal PTC, with SDSF < 40 mm identifying multifocal PTC patients with a good prognosis.

Multifocality of papillary thyroid carcinoma as a risk factor for disease recurrence

OBJECTIVES

Tumor multifocality or bilaterality is associated with increased risk of papillary thyroid carcinoma (PTC) recurrence. However, its prognostic value in clinical outcomes remains controversial. This study aimed to evaluate the association of multifocality or bilaterality with recurrence and survival after total thyroidectomy.

METHODS

This was a retrospective study of 2390 consecutive patients with pathologically confirmed PTC who underwent total thyroidectomy. Multifocality and bilaterality were decided based on the final pathology results, that is, if there were two or more tumor foci and bilateral location, respectively. Primary outcomes were recurrence-free survival (RFS). Cox proportional hazards regression analyses were used to assess the associations of multifocality, bilaterality, and other clinicopathological factors with RFS.

RESULTS

Multifocal and bilateral PTC were found in 892 (37.3%) and 593 (24.8%) patients, respectively. Multivariate analyses showed that multifocality, lymphovascular invasion, N category, and number of positive lymph node (>5) were significant independent variables predictive of RFS (all P < 0.05). Multifocality was associated with adjusted hazard ratios for RFS of 1.93 (95% confidence interval = 1.33-2.80; P = 0.001). In a subset analysis, the prognostic value of multifocality was found to be significant in those patients with PTC > 1 cm, but not in papillary thyroid microcarcinoma.

CONCLUSIONS

Tumor multifocality is an independent risk factor of PTC recurrence after total thyroidectomy. This indicate a more progressive state of disease, being included in risk stratification.

Risk of needing completion thyroidectomy for low-risk papillary thyroid cancers treated by lobectomy

Background

Low-risk differentiated thyroid cancers may, according to the American Thyroid Association (ATA) 2015 guidelines, be managed initially with lobectomy. However, definitive risk categorization requires pathological assessment of the specimen, resulting in completion thyroidectomy being recommended when discordance between preoperative and postoperative staging occurs. This study sought to establish the expected rate of completion thyroidectomy in patients with papillary thyroid cancer (PTC) treated by lobectomy.

Methods

Patients with PTC treated over 5 years (2013-2017 inclusive) and meeting the ATA criteria for lobectomy were identified from the prospectively developed database of a high-volume, university department of endocrine surgery. Concordance between the ATA initial and final recommendation, and the putative rate of completion thyroidectomy were calculated. Multivariable analysis was used to assess preoperative factors as predictors of the need for total thyroidectomy.

Results

Of 275 patients with PTC who met ATA preoperative criteria for lobectomy there was concordance between this and the final recommendation in 158 (57·5 per cent) and discordance in 117 (43·5 per cent). Most common reasons for discordance were: angioinvasion (30·8 per cent), local invasion (23·9 per cent) or both (20·5 per cent). Four patients (1·5 per cent) had permanent hypoparathyroidism. On multivariable analysis, age, sex, tumour size and family history did not independently predict the final treatment required.

Conclusion

Although many patients may be treated adequately with lobectomy, just under half would require completion thyroidectomy. Further work is needed on preoperative risk stratification but, before this, total thyroidectomy remains the treatment of choice for low-risk 1-4-cm PTC in the hands of high-volume thyroid surgeons who can demonstrate low complication rates.

Identifying risk factors for recurrence of papillary thyroid cancer in patients who underwent modified radical neck dissection

Background

Papillary thyroid cancer (PTC) patients with ipsilateral neck metastatic lymph node (LN) and those with contralateral neck metastatic LN belong to N1b. Only a few studies have reported on comparisons with regard to laterality of metastatic lateral LN. The aim of this study was to evaluate predictive factors for contralateral neck LN metastasis and to determine prognostic factors for recurrence in PTC patients with N1b.

Methods

This retrospective study reviewed the medical records of 390 PTC patients who underwent total thyroidectomy and central LN dissection plus ipsilateral or bilateral modified radical neck dissection (MRND) between January 2004 and December 2012.

Results

During a median follow-up of 81 (range, 6–156) months, 84 patients had a recurrence in any lesion. Male gender, a main tumor of more than 2 cm, number of metastatic central LN, number of harvested and metastatic lateral LN, total LN ratio, multifocality, bilaterality, and gross ETE had significance in the patients who underwent bilateral MRND. In multivariate analysis according to recurrence, patients with LN ratio > 0.44 in the central compartment (hazard ratio [HR], 1.890; 95% confidence interval [CI], 1.124–3.178; p = 0.015), LN ratio > 0.29 in the lateral compartment (HR, 2.351; 95% CI, 1.477–3.743; p < 0.001), and multifocality (HR, 1.583; 95% CI, 1.030–2.431; p = 0.036) were associated with worse RFS. However, the type of MRND was statistically significant only in univariate analysis.

Conclusions

Recurrence in N1b PTC patients is predicted by central neck LN ratio > 0.44, lateral neck LN ratio > 0.29, and multifocality of tumors. We suggest that patients with these factors should receive short-term follow-up using image modalities like ultrasonography and computed tomography.

A Rare Case of Multifocal Papillary Thyroid Cancer in Bilateral Thyroid Cysts

Papillary thyroid cancer (PTC) can present as a thyroid cyst. In its more aggressive form, PTC may be multifocal in nature and is associated with a poorer prognosis. In patients whom PTC is diagnosed incidentally after a diagnostic lobectomy, the decision whether to offer completion thyroidectomy is sometimes challenging to make if such patients fall in the 'low-to-intermediate' risk category. We present a case of a 55-year-old lady who had a predominantly cystic left thyroid nodule with no suspicious features on ultrasound as well as 2 subcentimetre simple right-sided cysts. She subsequently underwent left hemithyroidectomy, and this reported a T2 PTC in the thyroid cyst. This was followed by completion thyroidectomy which yielded the surprising finding of PTC in the two tiny right sided cysts. This case highlights the need for vigilance in managing patients with thyroid cysts even though thyroid ultrasound scan did not reveal any overt suspicious features.

The role of two tumor foci for predicting central lymph node metastasis in papillary thyroid carcinoma: A meta-analysis

BACKGROUND AND OBJECTIVE

Two tumor foci are the most common in multifocal papillary thyroid carcinoma, but whether they should be regarded as the indicator of central lymph node metastasis remains unclear. To investigate the role of two tumor foci for predicting central lymph node metastasis, we performed a meta-analysis of published studies.

METHODS

We performed a systematic literature search of PubMed, Embase and Web of Science prior to September 29, 2017. The relevant articles were examined and the eligible studies were included to assess the metastatic risk of central lymph node in papillary thyroid carcinoma with one, two and more than two (>2) tumor foci.

RESULTS

Five eligible studies included 4045 patients in this meta-analysis. Two tumor foci were the most common in multifocal papillary thyroid carcinoma (63.8%, 939/1471). Multifocality group showed a higher risk of central lymph node metastasis compared with unifocality group (odds ratio: 1.58, 95% confidence interval: 1.37-1.81). The risk of central lymph node metastasis was higher in two tumor foci group than unifocality group (odds ratio: 1.38, 95% confidence interval: 1.17-1.62). However, this risk in two tumor foci group was lower than >2 tumor foci group (odds ratio: 0.62, 95% confidence interval: 0.42-0.92). Begg's test revealed no obvious publication bias.

CONCLUSION

This meta-analysis suggested that two tumor foci should be regarded as the predictive factor of central lymph node metastasis, but the role of it was less important than three or more than three tumor foci. Understanding the role of two tumor foci for predicting central lymph node metastasis may help clinicians make an optimal decision of treatment and the extent of surgery for multifocal papillary thyroid carcinoma.

The Prognostic Value of Tumor Multifocality in Clinical Outcomes of Papillary Thyroid Cancer

CONTEXT

Multifocality is often treated as a risk factor for papillary thyroid cancer (PTC), prompting aggressive treatments, but its prognostic value remains unestablished.

OBJECTIVE

To investigate the role of tumor multifocality in clinical outcomes of PTC.

METHODS

Multicenter study of the relationship between multifocality and clinical outcomes of PTC in 2638 patients (623 men and 2015 women) with median [interquartile range (IQR)] age of 46 (35 to 58) years and median (IQR) follow-up time of 58 (26 to 107) months at 11 medical centers in six countries. Surveillance, Epidemiology and End Results (SEER) data were used for validation.

RESULTS

Disease recurrence in multifocal and unifocal PTC was 198 of 1000 (19.8%) and 221 of 1624 (13.6%) (P < 0.001), with a hazard ratio of 1.55 [95% confidence interval (CI), 1.28 to 1.88], which became insignificant at 1.13 (95% CI, 0.93 to 1.37) on multivariate adjustment. Similar results were obtained in PTC variants: conventional PTC, follicular-variant PTC, tall-cell PTC, and papillary thyroid microcarcinoma. There was no association between multifocality and mortality in any of these PTC settings, whereas there was a strong association between classic risk factors and cancer recurrence or mortality, which remained significant after multivariate adjustment. In 1423 patients with intrathyroidal PTC, disease recurrence was 20 of 455 (4.4%) and 41 of 967 (4.2%) (P = 0.892) and mortality was 0 of 455 (0.0%) and 3 of 967 (0.3%) (P = 0.556) in multifocal and unifocal PTC, respectively. The results were reproduced in 89,680 patients with PTC in the SEER database.

CONCLUSIONS

Tumor multifocality has no independent risk prognostic value in clinical outcomes of PTC; its indiscriminate use as an independent risk factor, prompting overtreatments of patients, should be avoided.

Identifying the clonal relationship model of multifocal papillary thyroid carcinoma by whole genome sequencing

PURPOSE

To evaluate the application of whole genome sequencing (WGS) in determining the inter-foci clonal relationship of multifocal papillary thyroid carcinoma (mPTC).

METHODS

After reviewing PTC patient profiles, 8 cancer foci and germline control samples from 3 mPTC patients were analyzed by WGS. Single nucleotide variations (SNVs), copy number variation (CNV), structural variation and mutational signature were examined.

RESULTS

The multifocality rate of PTC was 35.1% and mPTC were shown to have larger primary tumor diameter, higher rate of lymph node metastasis and less number of accompanying non-cancerous lesions than single PTC in one or both gender groups. Out of the 8 cancer foci, 5 foci were identified as clonal-independent model with the rest 3 foci as clonal-derived model according to exonic SNVs spectrum. Non-exonic mutations provided compelling evidence at the genome-wide level for the classification. Specific CNV and 12 mutational signatures were also identified.

CONCLUSIONS

WGS could be an impressive tool in clonal relationship determination of PTC by providing a panoramic view of genome-wide somatic mutations. The substantial sequencing data provided additional information that could help studying the mechanism of carcinogenesis.