Implications of Extrathyroidal Extension Invading Only the Strap Muscles in Papillary Thyroid Carcinomas

Risk factors and distribution pattern of lateral lymph node recurrence after central neck dissection for cN1a papillary thyroid carcinoma

BACKGROUND

The indication and extent of selective lateral neck dissection (LND) for cN1a papillary thyroid carcinoma (PTC) remain uncertain. The present study aimed to identify potential predictors and distribution pattern of lateral lymph node recurrence (LLNR) after central neck dissection in cN1a PTC patients.

METHODS

The cN1a PTC patients who underwent initial central neck dissection at our centre were retrospectively reviewed, and the median follow-up period was 6.8 years. Reoperation with LND was performed when LLNR was confirmed. Risk factors for LLNR were identified, and the metastatic status of each lateral level was recorded.

RESULTS

Of the 310 patients enrolled in the present study, fifty-eight patients (18.7%) presented with LLNR. Six independent factors, including tumour diameter, pathological T4 stage, number of involved central lymph nodes, pTNM stage, extrathyroidal extension, and I131 treatment (P values < 0.05) were identified via multivariate analysis. LLNR was found at level II in 26 patients (44.8%), level III in 38 patients (65.5%), level IV in 30 patients (51.7%), and level V in 8 patients (13.8%). The number of positive lateral lymph nodes at levels II, III, IV and V was 44 (22.9%), 76 (39.6%), 63 (32.8%), and 9 (4.9%), respectively.

CONCLUSIONS

For cN1a PTC patients who underwent central neck dissection, tumour diameter ≥ 2 cm, pathological T4 stage, number of involved central lymph nodes ≥ 3, pTNM stage III-IV, extrathyroidal extension, and failure to receive I131 treatment were independent predictors of LLNR, which was more likely to occur at levels III and IV.

Prognostic significance of T3b in papillary thyroid carcinoma: Appropriateness of classifying T3bN0M0 in patients aged 55 years or older into stage II

BACKGROUND

Papillary thyroid carcinoma (PTC) often extends to adjacent organs. According to the 8th Tumor-Node-Metastasis Classification, extension to the strap muscles was graded as T3b. We investigated the prognostic impact of T3b and the appropriateness of T3b in patients aged ≥55 years who were classified as stage II.

METHODS

We enrolled 7811 patients with M0 PTC who underwent initial surgery at the Kuma Hospital (Kobe, Japan) between January 2007 and December 2016. Tumor extension was divided into T3b, T4a1 (extension to the tracheal adventitia, tracheal cartilage, esophageal muscle layer, recurrent laryngeal nerve, cricothyroid, and inferior constrictor muscles), and sT4a2 (extension to the subcutaneous soft tissues, tracheal mucosa, esophageal mucosa, internal jugular vein, brachiocephalic vein, larynx, pharynx, and sternocleidomastoid muscle).

RESULTS

In patients ≥55 years, the local recurrence-free survival (LR-FS), distant recurrence-free survival (DR-FS), and cause-specific survival (CSS) rates of T3bN0M0 were significantly poorer than those of T1/T2N0M0 but did not significantly differ from those of T3aN0M0. The LR-FS, DR-FS, and CSS rates of T3b stage II patients did not differ from those of T4a1 stage III patients but were significantly better than those of T4a2 stage III patients. T3b was an independent predictor of local recurrence and distant recurrence but not of death due to carcinoma in the multivariate analysis. In patients aged <55 years with M0 PTC, T3b had no prognostic value in both analyses.

CONCLUSIONS

T3bM0 patients are appropriate to be classified as stage II in patients ≥55 years but be kept in stage I in patients <55 years.

Impact of Tumor Size on Prognosis in Differentiated Thyroid Cancer with Gross Extrathyroidal Extension to Strap Muscles: Redefining T3b

The prognostic significance of tumor size in T3b differentiated thyroid cancer (DTC) remains debated and underexplored. This study aimed to examine the varying impact of T3b based on tumor size, analyzing disease-specific survival, disease-free survival, and overall survival. A retrospective review of 6282 DTC patients who underwent thyroid surgery at Seoul St. Mary's Hospital from September 2000 to December 2017 was conducted. T3b was classified into three subcategories, T3b-1 (≤2 cm), T3b-2 (2-4 cm), and T3b-3 (>4 cm), using the same size criteria for T1, T2, and T3a. T3b-1 showed no significant difference in disease specific survival compared to T1, and both disease-free and disease-specific survival curves were sequentially ranked as T1, T3b-1, T2, T3a, T3b-2, and T3b-3. The modified T category, reclassifying T3b-1 as T1, demonstrated superior staging performance compared to the classic T category (c-index: 0.8961 vs. 0.8959 and AUC: 0.8573 vs. 0.8518). Tumors measuring 2 cm or less within the T3b category may require downstaging, and a modified T category could improve the precision of prognostic staging compared to the current T category.

Radiofrequency ablation for capsular-located versus noncapsular-located papillary thyroid microcarcinoma: a propensity score matching study of 1095 patients

OBJECTIVES

To assess the safety and efficacy of radiofrequency ablation (RFA) for capsular-located papillary thyroid microcarcinoma (PTMC) in a large cohort and to compare its outcomes with those of noncapsular-located PTMC.

METHODS

We retrospectively reviewed patients who underwent RFA for solitary capsular-located and noncapsular-located low-risk PTMC (n = 1095) from June 2014 to October 2020. To balance confounding variables between capsular and noncapsular groups, we employed the 1:1 propensity score matching approach. We evaluated and compared tumor changes, disease progression, and complications in both groups. Furthermore, we analyzed the association between capsular location and disease progression using multivariable Cox regression.

RESULTS

During a mean follow-up time of 29.86 ± 16.14 months and 29.73 ± 15.69 months, no substantial difference was observed between capsular and noncapsular groups in the latest volume (0.83 ± 3.66 mm3 vs. 0.85 ± 3.67 mm3, p = 0.44) and volume reduction ratio (99.29 ± 4.04% vs. 99.43 ± 3.03%, p = 0.43), and cumulative disappearance rate (87.87% vs. 86.07%, p = 0.31). In addition, no significant differences were observed in complication incidence (1.35% vs. 1.12%, p = 0.76) and progression-free survival (p = 0.53). Based on adjusted multivariate Cox proportional hazard analysis, the association between capsular location and disease progression was nonsignificant (all p > 0.05).

CONCLUSION

This study demonstrates that the short-term outcomes of RFA for capsular-located PTMCs are comparable to those of noncapsular-located PTMCs. These findings indicate that RFA may be a viable and effective alternative for eligible patients with solitary capsular-located PTMC.

CLINICAL RELEVANCE STATEMENT

Radiofrequency ablation may serve as a safe and effective alternative treatment method for eligible patients with capsular-located and noncapsular-located papillary thyroid microcarcinoma.

KEY POINTS

• The safety and efficacy of radiofrequency ablation for capsular-located and noncapsular-located papillary thyroid microcarcinomas were comparable. • Disease progression did not differ significantly between capsular-located and noncapsular-located papillary thyroid microcarcinomas. • The incidence of complications for capsular-located papillary thyroid microcarcinoma was low.

Interplay of metabolic dysfunction-associated fatty liver disease and papillary thyroid carcinoma: insights from a Chinese cohort

PURPOSE

Thyroid cancer is one of a set of extrahepatic cancers that closely linked to metabolic dysfunction-associated fatty liver disease (MAFLD). However, the connection between MAFLD and the characteristics of papillary thyroid cancer (PTC) remains unexplored.

METHODS

Between Jan 2020 and Oct 2022, surgical cases of PTC patients were examined at the first Affiliated Hospital of Wenzhou Medical University. Clinical data extracted from the electronic medical system underwent a rigorous comparison between two groups, classified based on MAFLD criteria, using logistic regression analysis.

RESULTS

In this study of 4,410 PTC patients, 18.3% had MAFLD. MAFLD emerged as a distinct risk factor for lymph node metastasis (OR = 1.230, 95% CI 1.018-1.487) in this cohort, especially in females (OR = 1.321, 95% CI 1.026-1.702) and those with BMI ≥ 23 kg/m2 (OR = 1.232, 95% CI 1.004-1.511). The presence of MAFLD was found to significantly elevate the risk of BRAF V600E mutation in both subgroups characterized by FIB-4 score ≥ 1.3 (OR = 1.968, 95% CI 1.107-3.496) and BMI < 23 kg/m2 (OR = 2.584, 95% CI 1.012-6.601). Moreover, among the subset of individuals without non-alcoholic fatty liver disease (NAFLD), it was noted that MAFLD considerably increased the likelihood of tumor multifocality (OR = 1.697, 95% CI 1.111-2.592). Nevertheless, MAFLD did not exhibit any correlation with increased tumor size, extra-thyroidal extension (ETE), or later TNM stage in PTC.

CONCLUSION

In this cross-sectional study, we discovered a significant association between MAFLD and increased occurrences of lymph node metastasis. Furthermore, MAFLD was linked to a higher chance of BRAF V600E mutation and the presence of multiple tumors in certain subgroups.

Microscopic extrathyroidal extension does not affect the prognosis of patients with papillary thyroid carcinoma: A propensity score matching analysis

Background

Extrathyroidal extension (ETE) in papillary thyroid carcinoma (PTC) can be divided into two categories based on different degrees of invasion: microscopic ETE (micro-ETE) and macroscopic ETE (macro-ETE). At present, there is a consensus that macro-ETE significantly affects PTC prognosis, while the prognostic significance of micro-ETE remains controversial.

Methods

The clinicopathological and follow-up data for PTC patients who underwent surgical treatment at the Hangzhou First People's Hospital between 2015 and 2018 were retrospectively analyzed. According to the degree of ETE, patients were divided into three groups: non-ETE, micro-ETE and macro-ETE. Cox regression analysis was performed to evaluate the effect of ETE on recurrence-free survival (RFS). The propensity score matching (PSM) method was used to reduce the interference of confounding factors, and Kaplan-Meier curves were utilized to compare the RFS.

Results

Both micro- and macro-ETE were associated with some aggressive tumor features, including tumor size, multifocality, and lymph node metastasis. Univariate and multivariate Cox regression analyses showed that macro-ETE was an independent risk factor for recurrence, while micro-ETE was not associated with recurrence. The K-M curves showed that RFS for micro-ETE and non-ETE were not statistically different before and after PSM, while RFS for macro-ETE was significantly shorter than that for non-ETE.

Conclusion

The presence of micro-ETE in PTC did not affect prognosis of patients, suggesting that its treatment should be consistent with the treatment for intrathyroidal tumors. The surgical method and the necessity for radioiodine therapy should be carefully evaluated to reduce overtreatment.

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.

Optimal Cutoff Values of the Contact Angle of Tumor on Sonography System for Predicting Extrathyroidal Extension of Papillary Thyroid Carcinoma by Tumor Location

Background

Extrathyroidal extension (ETE) significantly affects the treatment strategy for thyroid cancer. We present a new method to predict ETE of papillary thyroid carcinoma (PTC).

methods

We enrolled 1 481 patients with PTCs. The ETE was classified into minimal and gross ETE. Using the novel "contact angle of the tumor on sonography" (CATS) system, we calculated optimal cutoffs for predicting ETE according to tumor location and compared the diagnostic performance to that of previous methods.

Results

The optimal cutoff angles for predicting anterior minimal and gross ETE were 41.5° and 49.4°, respectively, while those for posterior ETE were 39.8° and 54.6°, respectively. The optimal cutoff angle predicting tracheal ETE was 88.0°. The diagnostic performance was comparable to that of previous methods.

Conclusion

The CATS method for predicting ETE is a valuable alternative.

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.

Ultrasound image-based deep learning to assist in diagnosing gross extrathyroidal extension thyroid cancer: a retrospective multicenter study

Background

The presence of gross extrathyroidal extension (ETE) in thyroid cancer will affect the prognosis of patients, but imaging examination cannot provide a reliable diagnosis for it. This study was conducted to develop a deep learning (DL) model for localization and evaluation of thyroid cancer nodules in ultrasound images before surgery for the presence of gross ETE.

Methods

From January 2016 to December 2021 grayscale ultrasound images of 806 thyroid cancer nodules (4451 images) from 4 medical centers were retrospectively analyzed, including 517 no gross ETE nodules and 289 gross ETE nodules. 283 no gross ETE nodules and 158 gross ETE nodules were randomly selected from the internal dataset to form a training set and validation set (2914 images), and a multitask DL model was constructed for diagnosing gross ETE. In addition, the clinical model and the clinical and DL combined model were constructed. In the internal test set [974 images (139 no gross ETE nodules and 83 gross ETE nodules)] and the external test set [563 images (95 no gross ETE nodules and 48 gross ETE nodules)], the diagnostic performance of DL model was verified based on the pathological results. And then, compared the results with the diagnosis by 2 senior and 2 junior radiologists.

Findings

In the internal test set, DL model demonstrated the highest AUC (0.91; 95% CI: 0.87, 0.96), which was significantly higher than that of two senior radiologists [(AUC, 0.78; 95% CI: 0.71, 0.85; P < 0.001) and (AUC, 0.76; 95% CI: 0.70, 0.83; P < 0.001)] and two juniors radiologists [(AUC, 0.65; 95% CI: 0.58, 0.73; P < 0.001) and (AUC, 0.69; 95% CI: 0.62, 0.77; P < 0.001)]. DL model was significantly higher than clinical model [(AUC, 0.84; 95% CI: 0.79, 0.89; P = 0.019)], but there was no significant difference between DL model and clinical and DL combined model [(AUC, 0.94; 95% CI: 0.91, 0.97; P = 0.143)]. In the external test set, DL model also demonstrated the highest AUC (0.88, 95% CI: 0.81, 0.94), which was significantly higher than that of one of senior radiologists [(AUC, 0.75; 95% CI: 0.66, 0.84; P = 0.008) and (AUC, 0.81; 95% CI: 0.72, 0.89; P = 0.152)] and two junior radiologists [(AUC, 0.72; 95% CI: 0.62, 0.81; P = 0.002) and (AUC, 0.67; 95 CI: 0.57, 0.77; P < 0.001]. There was no significant difference between DL model and clinical model [(AUC, 0.85; 95% CI: 0.79, 0.91; P = 0.516)] and clinical + DL model [(AUC, 0.92; 95% CI: 0.87, 0.96; P = 0.093)]. Using DL model, the diagnostic ability of two junior radiologists was significantly improved.

Interpretation

The DL model based on ultrasound imaging is a simple and helpful tool for preoperative diagnosis of gross ETE thyroid cancer, and its diagnostic performance is equivalent to or even better than that of senior radiologists.

Funding

Jiangxi Provincial Natural Science Foundation (20224BAB216079), the Key Research and Development Program of Jiangxi Province (20181BBG70031), and the Interdisciplinary Innovation Fund of Natural Science, Nanchang University (9167-28220007-YB2110).

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

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

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.

Dexamethasone for Postoperative Nausea and Vomiting in Papillary Thyroid Carcinoma Patients: A Randomized Clinical Trial

BACKGROUND

Postoperative nausea and vomiting (PONV) frequently occur after thyroidectomy. Previous studies have investigated the effects of preoperative dexamethasone for alleviating PONV in various cancers, but studies focused on papillary thyroid carcinoma (PTC) were limited. This study aimed to determine the efficacy of a single preoperative dose of dexamethasone to prevent PONV in patients with PTC.

METHODS

This single-center, parallel-group, double-blind, placebo-controlled clinical trial was conducted on patients with PTC in West China Hospital. Patients were randomized 1:1 into Group Dex (preoperative 8-mg dexamethasone) or Group Control (0.9% NaCl as control). The primary outcome was the incidence and severity of PONV. The secondary outcomes included postoperative pain, vocal dysfunction, and adverse events.

RESULTS

Six hundred participants were recruited and randomized. The total incidence of PONV was 33.3% (200 of 600 patients; 95% CI, 29.6-37.1). In the intention-to-treat analysis, PONV occurred in 81 of 300 patients (27.0%; 95% CI, 21.9-32.1) in Group Dex and in 119 of 300 patients (39.7%; 95% CI, 34.1-45.2) in Group Control (p = 0.001), and the absolute risk reduction was 12.7% (95% CI, 5.1-20.0). Patients in Group Dex reported fewer antiemetic requirements than those in Group Control (p = 0.004). Multivariate analysis indicated that dexamethasone administration (OR = 0.546; 95% CI, 0.383-0.777; p = 0.001) was associated with a reduced rate of PONV. Dexamethasone treatment also contributed to alleviating postoperative pain and improving subjective vocal dysfunction, with no increase in adverse events.

CONCLUSIONS

A single dose of dexamethasone is effective and safe for preventing PONV in PTC patients.

The clinical impact of extrathyroidal extensions on prognoses in pediatric differentiated thyroid cancers

BACKGROUND

The prognostic impact of extrathyroidal extensions (ETE) on clinical outcomes has not been well studied in pediatric thyroid cancers. The aim of this study was to analyze the clinicopathological characteristics and clinical outcomes according to the extent of ETE in pediatric and adolescent thyroid cancers.

METHODS

This study retrospectively reviewed 89 papillary thyroid carcinoma (PTC) patients less than 19 years of age who underwent total thyroidectomy with central neck dissections (CND) between 1997 and 2018. We compared the clinicopathological features among three groups: no ETE, microscopic ETE, and gross ETE.

RESULTS

The median follow-up time was 111 months. The mean age was 15.3 years and the mean tumor size was 2.4 cm. Tumor sizes larger than 2 cm (OR = 9.2, p = 0.001), exhibited bilaterality (OR = 4.3, p = 0.006), were an aggressive variant (OR = 5.8, p = 0.006), and exhibited central lymph node metastasis (OR = 1.3, p = 0.018), lateral lymph node metastasis (OR = 9.2, p = 0.001), recurrence (OR = 3.9, p = 0.038), and distant metastasis (OR = 4.4, p = 0.016) were associated with gross ETE. There was no remarkable difference in clinicopathological characteristics between the no ETE group and microscopic ETE group, except for aggressive variants (OR = 5.5, p = 0.008). There was a significant difference in recurrence-free survival (RFS) rates according to the extent of ETE (p = 0.025). Furthermore, the distant metastasis-free survival curve presented a significant difference among the three groups (p = 0.018). Both microscopic ETE and gross ETE were significantly associated with worse prognoses in pediatric thyroid cancers.

CONCLUSIONS

We recommend that microscopic ETE should be included in the intermediate risk category and that gross ETE should be stratified in the high risk group in future revisions of ATA pediatric guidelines.

Clinical and prognosis value of the number of metastatic lymph nodes in patients with papillary thyroid carcinoma

Objective

It has been reported that papillary thyroid carcinoma (PTC) patients with lymph node metastasis (LNM) are largely associated with adverse outcomes. The present study aimed to assess the correlation between the number of metastatic lymph nodes (NMLNs) and clinical prognosis in patients with PTC.

Methods

We retrospectively reviewed the medical records of patients with PTC who underwent initial thyroid cancer surgery in Renmin Hospital of Wuhan University between 2017 and 2019. A total of 694 patients with PTC and cervical lymph node dissection as well as a total checked number of lymph nodes ≥ 5 were involved in this study. The clinicopathological characteristics of patients were compared according to NMLNs, the number of central cervical lymph nodes (CLNs) and the number of lateral lymph nodes (LLNs).

Results

NMLNs > 5, CLNs > 5 and LLNs > 5 were 222 (32.0%), 159 (24.3%) and 70 (10.1%) seen in the analyzed samples, respectively. Young patients, patients with larger tumor diameter, bilaterality, multifocality and gross extrathyroidal extension (ETE) were more inclined to NMLNs > 5, CLNs > 5 and LLNs > 5 (P < 0.05). It was found that the recurrence-free survival among pN1 patients was significantly discrepant between different groups (NMLNs ≤ 5/5: P = 0.001; LLNs ≤ 5/5: P < 0.001). In multivariate logistic regression analysis, patients aged < 55 years (OR = 1.917), primary tumor size > 10 mm (OR = 2.131), bilaterality (OR = 1.889) and tumor gross ETE (OR = 2.759) were independent predictors for high prevalence of total NMLNs > 5 (P < 0.05). Specially, patients aged < 55 years (OR = 2.864), primary tumor size > 10 mm (OR = 2.006), and tumor gross ETE (OR = 2.520) were independent predictors for high prevalence of CLNs > 5 (P < 0.01); Bilaterality (OR = 2.119), CLNs > 5 (OR = 6.733) and tumor gross ETE (OR = 4.737) were independent predictors for high prevalence of LLNs > 5 (P < 0.05).

Conclusions

In conclusion, it is evident that NMLNs is related to the invasive clinicopathological features and adverse outcome of patients with PTC which should be correctly evaluated to provide an appropriate guidance for reasonable treatment and careful follow-up.

Prognostic Impact of Microscopic Extra-Thyroidal Extension (mETE) on Disease Free Survival in Patients with Papillary Thyroid Carcinoma (PTC)

Background: This study assessed the risk of reduced disease-free survival (DFS) and poor clinical outcome in patients with papillary thyroid carcinomas (PTC) with microscopic extra-thyroidal extension (mETE), as compared to PTC patients without mETE. Methods: Retrospective analysis of a prospective database of patients treated by total thyroidectomy and radioactive iodine (RAI) with a five-year follow-up and tumors < 40 mm. In total, 303 patients were analyzed: 30.7% presented tumors with mETE, and 69.3% without. mETE was defined as extra-thyroidal invasion without skeletal muscle involvement. The primary outcome, DFS, was defined as the interval between initial treatment and any subsequent PTC-related treatment. The second outcome was the clinical status at five years. Results: In univariate analyses, the five-year DFS was significantly lower for tumors with mETE (62.4% versus 88.1%, p < 0.001). In multivariate analysis, mETE and massive lymph node involvement (LNI) were independent prognostic factors, associated respectively with a hazard ratio of 2.55 (95% CI 1.48−4.40) and 8.94 (95% CI 4.92−16.26). mETE was significantly associated with a pejorative clinical outcome at five years, i.e., biochemical/indeterminate response and structural persistence (Respectively OR 1.83 (95% CI 0.83; 4.06) and OR 4.92 (95% CI 1.87; 12.97)). Conclusion: Our results suggest that mETE is an independent poor prognosis factor of reduced DFS and predictive of poor clinical outcome.

Evaluation of plasma exosomal miRNAs as potential diagnostic biomarkers of lymph node metastasis in papillary thyroid carcinoma

PURPOSE

The early diagnosis of lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC) is clinically important, as it can aid in treatment decision-making and improve prognosis. In the present study, we aimed to identify whether plasma exosomal miRNAs could be potential diagnostic markers of LNM in PTC.

METHODS

Profiles of plasma exosomal miRNAs were screened using miRNA microarrays. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed in the validation and diagnostic sets to select candidate exosomal miRNAs. Finally, receiver operating characteristic (ROC) curves were generated to evaluate the efficiency of target exosomal miRNAs in distinguishing PTC-N1 patients from PTC-N0 patients.

RESULTS

In total, 197 miRNAs were found to be differentially expressed in the testing set. Based on the qRT-PCR results, the expression of miR-6774-3p (p < 0.001) and miR-6879-5p (p < 0.001) in the PTC-N1 patients was significantly higher than that in the controls. The AUC values of plasma exosomal miR-6774-3p (0.802; 95% CI, 0.724-0.879) and miR-6879-5p (0.787; 95% CI, 0.706-0.867) and their combination (0.914; 95% CI, 0.865-0.962) were higher than those of the total miRNAs directly isolated from plasma. Moreover, the expression of exosomal miRNAs was stable after treatment with RNase A, prolonged incubation, or repeated freezing and thawing.

CONCLUSIONS

The two plasma exosomal miRNAs (miR-6774-3p and miR-6879-5p) and their combination could serve as new promising biomarkers for the diagnosis of LNM in PTC patients.

Reevaluation of Criteria and Establishment of Models for Total Thyroidectomy in Differentiated Thyroid Cancer

Introduction

After the publication of the 2015 American Thyroid Association (ATA) guidelines, the indication for total thyroidectomy (TT) was reported to be underestimated before surgery, which may lead to a substantial rate of secondary completion thyroidectomy (CTx).

Methods and Materials

We retrospectively analyzed differentiated thyroid cancer patients from Wuhan Union Hospital (WHUH). Univariate analysis was performed to evaluate all preoperative and intraoperative factors. New models were picked out by comminating and arranging all significant factors and were compared with ATA and National Comprehensive Cancer Network (NCCN) guidelines in the multicenter prospective Differentiated Thyroid Cancer in China (DTCC) cohort.

Results

A total of 5,331 patients from WHUH were included. Pre- and intraoperative criteria individually identified 906 (17.0%) and 213 (4.0%) patients eligible for TT. Among all factors, age <35 years old, clinical N1, and ultrasound reported local invasion had high positive predictive value to predict patients who should undergo TT. Accordingly, we established two new models that minorly revised ATA guidelines but performed much better. Model 1 replaced “nodule size >4 cm” with “age <35 years old” and achieved significant increase in the sensitivity (WHUH, 0.711 vs. 0.484; DTCC, 0.675 vs. 0.351). Model 2 simultaneously demands the presence of “nodule size >4 cm” and “age <35 years old,” which had a significant increase in the specificity (WHUH, 0.905 vs. 0.818; DTCC, 0.729 vs. 0.643).

Conclusion

All high-risk factors had limited predictive ability. Our model added young age as a new criterion for total thyroidectomy to get a higher diagnostic value than the guidelines.

Prognostic implications of extranodal extension in papillary thyroid carcinomas: A propensity score matching analysis and proposal for incorporation into current tumor, lymph node, metastasis staging

BACKGROUND

The current American Joint Committee on Cancer tumor, lymph node, metastasis cancer staging system for papillary thyroid carcinoma places low weight on extranodal extension. This study examined the prognostic implications of extranodal extension in papillary thyroid carcinoma patients and attempted to design a new staging system incorporating extranodal extension.

METHODS

We reviewed data from 6,165 consecutive papillary thyroid carcinoma patients from 2012 to 2018. Patients with extrathyroidal extension or extranodal extension were included and then divided into 3 groups: extrathyroidal extension (papillary thyroid carcinoma with extrathyroidal extension but without extranodal extension, N = 457); extranodal extension (papillary thyroid carcinoma with extranodal extension but without extrathyroidal extension, N = 116); and extrathyroidal extension and extranodal extension (papillary thyroid carcinoma with both extrathyroidal extension and extranodal extension, N = 116). Recurrence-free survival and cancer-specific survival were compared before and after adjusting for differences using propensity score matching owing to observed heterogeneity in baseline characteristics in the original cohort. Recurrence-free survival and cancer-specific survival were also compared between patients with and without extranodal extension after matching at a 1:1 ratio. Cox proportional hazards regression analyses were used to identify the relationships of factors associated with structural recurrent disease in the node-positive subset. Then a new staging system incorporating extranodal extension was established, and the discrimination of the new staging system for recurrence-free survival and cancer-specific survival was investigated.

RESULTS

Of the 6,165 patients with papillary thyroid carcinoma, extrathyroidal extension was found in 573 (9.3%) patients, and extranodal extension was observed in 232 (3.8%) patients. The recurrence-free survival and cancer-specific survival rates of patients with extranodal extension were similar to those of patients with extrathyroidal extension (all P > .05). Patients with extrathyroidal extension and extranodal extension experienced worse recurrence-free survival than patients with extrathyroidal extension or extranodal extension and even worse cancer-specific survival than patients with extrathyroidal extension (all P < .05). The recurrence-free survival and cancer-specific survival rates of patients with extranodal extension were worse than those of patients without extranodal extension (P = .003; P = .048). Cox proportional hazards regression analysis demonstrated that after propensity score matching, extranodal extension (hazard ratio 1.911; 95% confidence interval 1.568-3.609; P < .001) remained an independent predictor of structural recurrent disease in patients with node-positive papillary thyroid carcinoma. After incorporating extranodal extension into the current tumor, lymph node, metastasis classification, the new staging system presented a better discrimination for recurrence-free survival and cancer-specific survival for those with lymph node metastasis.

CONCLUSION

Papillary thyroid carcinoma patients with extranodal extension present worse prognosis, and incorporating extranodal extension in tumor, lymph node, metastasis classification identifies poor-risk patients more accurately.

Analysis of Risk Factors of Level V Lymphatic Metastasis for Papillary Thyroid Carcinoma with pN1b

Objective

To explore the risk factors of level V lymphatic metastasis in papillary thyroid carcinoma (PTC) patients with pN1b.

Methods

Patients were selected if they presented with a suspicious level III or IV lymph node metastasis and underwent surgery by hemi or total thyroidectomy with a lymph node dissection (levels III, IV, VI, and VII). For these patients, if frozen section showed a positive level III or IV node, then levels II and V nodes were resected. Univariate analysis was performed using the chi-square test for some factors, including age, sex, tumor location, multifocal lesions, tumor size, local invasion of primary focus, status of cervical lymphatic metastasis, TNM staging, tumor deposits (independent tumor nodules), and the metastasis to more than 5 central lymph nodes. Then, the factors with statistical significance indicated by the above univariate analysis underwent multivariate analysis.

Results

Univariate analysis indicated that the level V lymphatic metastasis was significantly associated with simultaneous metastases to levels II, III, and IV, simultaneous metastases to levels III and IV, and tumor deposits (all p < 0.05), but it was not significantly associated with age, sex, tumor location, multifocal lesions, tumor size, local invasion of primary focus, other cervical lymphatic metastasis, TNM staging, and the metastases to more than 5 central lymph nodes (all p > 0.05). Multivariate analysis suggested that the simultaneous metastases to levels III and IV and tumor deposits were the risk factors of level V lymphatic metastasis.

Conclusion

The simultaneous metastases to levels III and IV and tumor deposits are independent risk factors of level V lymphatic metastasis. The patients with pN1b PTC who have simultaneous metastases to levels III and IV or/and tumor deposits may have the risk of level V lymph node metastasis.

How to identify indolent thyroid tumors unlikely to recur and cause cancer death immediately after surgery-Risk stratification of papillary thyroid carcinoma in young patients

Current histopathological diagnosis methods cannot distinguish the two types of thyroid carcinoma: clinically significant carcinomas with a potential risk of recurrence, metastasis, and cancer death, and clinically insignificant carcinomas with a slow growth rate. Both thyroid tumors are diagnosed as "carcinoma" in current pathology practice. The clinician usually recommends surgery to the patient and the patient often accepts it because of cancer terminology. The treatment for these clinically insignificant carcinomas does not benefit the patient and negatively impacts society. The author proposed risk stratification of thyroid tumors using the growth rate (Ki-67 labeling index), which accurately differentiates four prognostically relevant risk groups based on the Ki-67 labeling index, ≥30%, ≥10 and <30%, >5 and <10%, and ≤5%. Indolent thyroid tumors with an excellent prognosis have the following four features: young age, early-stage (T1-2 M0), curatively treated, and low proliferation index (Ki-67 labeling index of ≤5%), and are unlikely to recur, metastasize, or cause cancer death. Accurate identification of these indolent tumors helps clinicians select more conservative treatments to avoid unnecessary aggressive (total thyroidectomy followed by radio-active iodine) treatments. Clinicians can alleviate the fears of patients by confirming these four features, including the low proliferation rate, in a pathology report immediately after surgery when patients are most concerned.

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.

The extent of surgery for low-risk 1-4 cm papillary thyroid carcinoma: a catch-22 situation. A retrospective analysis of 497 patients based on the 2015 ATA Guidelines recommendation 35

PURPOSE

The adequate extent of surgery for 1-4 cm low-risk papillary thyroid carcinoma (PTC) is unclear. Our objective was to analyze the applicability of the 2015 ATA Guidelines recommendation 35B (R35) for the management low-risk PTC.

METHODS

This multicentre study included patients with low-risk PTC who had undergone total thyroidectomy (TT). Retrospectively we selected those who met the R35 criteria for the performance of a thyroid lobectomy (TL). The aim was to identify the proportion of low-risk PTC patients treated using TT who would have required reintervention had they had a TL in accordance with R35.

RESULTS

We identified 497 patients (400 female; 80.5%). Median tumor size (mm): 21.2 (11-40). A tumor size ≥2 cm was found in 252 (50.7%). Most of them, 320 (64.4%), were in Stage I (AJCC 7th Edition). Following R35, 286 (57.5%) would have needed TT. Thus, they would have required a second surgery had they undergone TL. The indications for reintervention would have included lymph node involvement (35%), extrathyroidal extension (22.9%), aggressive subtype (8%), or vascular invasion (22.5%). No presurgical clinical data predict TT.

CONCLUSIONS

The appropriate management of low-risk PTC is unclear. Adherence to ATA R35 could lead to a huge increase in reinterventions when a TL is performed, though the need for them would be questionable. In our sample, more than half of patients (57.5%) who may undergo a TL for a seemingly low-risk PTC would have required a second operation to satisfy international guidelines, until better preoperative diagnostic tools become available.

Impact of Gross Strap Muscle Invasion on Outcome of Differentiated Thyroid Cancer: Systematic Review and Meta-Analysis

Background: Gross strap muscle invasion (gSMI) in patients with differentiated thyroid cancer (DTC) was defined as high-risk recurrent group in the 2015 American Thyroid Association guidelines. However, controversy persists because several studies suggested gSMI had little effect on disease outcome. Herein, a systematic review and meta-analysis was conducted to investigate impact of gSMI on outcome of DTC. Methods: A systematic search of electronic databases (PubMed, EMBASE, Cochrane Library, and MEDLINE) for studies published until February 2020 was performed. Case-control studies and randomized controlled trials that studied the impact of gSMI on outcome of DTC were included. Results: Six studies (all retrospective studies) involving 13,639 patients met final inclusion criteria. Compared with no extrathyroidal extension (ETE), patients with gSMI were associated with increased risk of recurrence (P = 0.0004, OR, 1.46; 95% CI: 1.18-1.80) and lymph node metastasis (LNM) (P < 0.00001, OR 4.19; 95% CI: 2.53-6.96). For mortality (P = 0.34, OR 1.47; 95% CI: 0.67-3.25), 10 year disease-specific survival (P = 0.80, OR 0.91; 95% CI: 0.44-1.88), and distant metastasis (DM) (P = 0.21, OR 2.94; 95% CI: 0.54-15.93), there was no significant difference between gSMI and no ETE group. In contrast with maximal ETE(extension of the primary tumor to the trachea, esophagus, recurrent laryngeal nerve, larynx, subcutaneous soft tissue, skin, internal jugular vein, or carotid artery), patients with gSMI were associated with decreased risk of recurrence (P < 0.0001, OR, 0.58; 95% CI: 0.44-0.76), mortality (P = 0.0003, OR 0.20; 95% CI: 0.08-0.48), LNM (P = 0.0003, OR 0.64; 95% CI: 0.50-0.81), and DM (P = 0.0009, OR 0.28; 95% CI: 0.13-0.59). Conclusions : DTC patients with gSMI had a higher risk of recurrence and LNM than those without ETE. However, in contrast with maximal ETE, a much better prognosis was observed in DTC patients with only gSMI.

Isthmic Papillary Thyroid Carcinoma Presents a Unique Pattern of Central Lymph Node Metastasis

Purpose

Treatment protocols for occult central lymph node metastasis (LNM) associated with papillary thyroid cancer (PTC) located in the isthmus are debatable. We aimed to analyze the pattern of occult central LNM in isthmic PTC, including risk factors for bilateral paratracheal LNM.

Patients and Methods

Consecutive patients with PTC were recruited to this study. All patients underwent total thyroidectomy and prophylactic bilateral central neck dissection. The clinicopathologic features and distribution of central LNM were compared between the two groups, and risk factors for bilateral paratracheal LNM were analyzed.

Results

A total of 174 patients with PTC were enrolled in this study, of whom 87 patients had isthmic PTC (study group) and 87 patients had lobe-originating PTC (control group). The two groups had comparable demographics and tumor features. There were higher frequencies of pretracheal LNM (P =0.001) and bilateral paratracheal LNM (P = 0.002) in the isthmic PTC group. Bilateral paratracheal LNM was significantly associated with age <55 years (P = 0.037), capsular invasion (P = 0.034), tumor location (isthmus) (P < 0.001), BRAF gene mutation (P = 0.013), and pretracheal LNM (P < 0.001). Isthmus location (odds ratio [OR]: 4.116, 95% confidence interval [CI]: 1.264–13.433, P = 0.019) and pretracheal LNM (OR: 3.422, 95% CI: 1.214–9.642, P = 0.020) were independent risk factors for bilateral paratracheal LNM.

Conclusion

Because of its unique anatomic location, isthmic PTC differs from PTC in the lobe with respect to pretracheal and bilateral paratracheal LNM, even in patients of comparable age, sex, tumor size, extrathyroidal extension, BRAF mutation, and pathologic TNM staging. The isthmus location was found to be an independent risk factor for bilateral paratracheal LNM. This information may contribute to the development of an appropriate surgical protocol for isthmic PTC.