Management of recurrent/persistent nodal disease in patients with differentiated thyroid cancer: a critical review of the risks and benefits of surgical intervention versus active surveillance

Enhancement on CT for preoperative diagnosis of metastatic lymph nodes in thyroid cancer: a comparison across experience levels

OBJECTIVES

To investigate the diagnostic performance and interobserver agreement of quantitative CT parameters indicating strong lymph node (LN) enhancement in differentiated thyroid cancer (DTC), comparing them with qualitative analysis by radiologists of varying experience.

MATERIALS AND METHODS

This study included 463 LNs from 399 patients with DTC. Three radiologists independently analyzed strong LN enhancement on CT. Qualitative analysis of strong enhancement was defined as LN cortex showing greater enhancement than adjacent muscles on the arterial phase. Quantitative analysis included the mean attenuation value (MAV) of LN on arterial phase (LNA) and venous phase (LNV), LNA normalized to the common carotid artery (NAVCCA), internal jugular vein (NAVIJV), and sternocleidomastoid muscle (NAVSCM), attenuation difference [AD; (LNA - MAVSCM)], and relative washout ratio [((LNA - LNV)/LNA) × 100]. The interobserver agreement and diagnostic performance of the quantitative and qualitative analyses were evaluated.

RESULTS

Interobserver agreement was excellent for all quantitative CT parameters (ICC, 0.83-0.94) and substantial for qualitative assessment (κ = 0.61). All CT parameters except for LNV showed good diagnostic performance for metastatic LNs (AUC, 0.81-0.85). NAVCCA (0.85, 95% CI: 0.8-0.9) and AD (0.85, 95% CI: 0.81-0.89) had the highest AUCs. All quantitative parameters except for NAVIJV had significantly higher AUCs than qualitative assessments by inexperienced radiologists, with no significant difference from assessments by an experienced radiologist.

CONCLUSION

Quantitative assessment of LN enhancement on arterial phase CT showed higher interobserver agreement and AUC values than qualitative analysis by inexperienced radiologists, supporting the need for a standardized quantitative CT parameter-based model for determining strong LN enhancement.

CLINICAL RELEVANCE STATEMENT

When assessing strong LN enhancement in DTC, quantitative CT parameters indicating strong enhancement can improve interobserver agreement, regardless of experience level. Therefore, the development of a standardized diagnostic model based on quantitative CT parameters might be necessary.

KEY POINTS

Accurate preoperative assessment of LN metastasis in thyroid cancer is crucial. Quantitative CT parameters indicating strong LN enhancement demonstrated excellent interobserver agreement and good diagnostic performance. Quantitative assessment of contrast enhancement offers a more objective model for the identification of metastatic LNs.

Thermal ablation for multifocal papillary thyroid microcarcinoma: a systematic review and meta-analysis

BACKGROUND

Clinical studies have indicated the potential safety and efficacy of thermal ablation (TA) in treating multifocal papillary thyroid microcarcinoma (MPTMC). However, a comprehensive systematic evaluation of its effectiveness was still lack.

METHODS

PubMed, EMBASE and Cochrane Library databases were systematically searched for studies published until October 23, 2023, that reported on the effectiveness of thermal ablation in the management of MPTMC. Data extraction and methodological quality assessment were independently conducted by two reviewers following the guidelines outlined in the PRISMA.

RESULTS

This systematic review and meta-analysis identified 389 tumors in 169 patients from four studies. After treatment with different TA, the combined rate of complete disappearance of MPTMC was 92.8% [95% confidence interval (CI): 68.2-100] and the combined rate of overall complications was 4.4% [95% CI: 1.5-8.5]. During the follow-up period, local tumor recurrence was observed in only 2 patients with a combined rate of 0.2% [95% CI: 0.0-2.6]; lymph node metastasis (LNM) was observed in 3 patients with a combined rate of 1.2% [95% CI: 0-4.1]. Additionally, 6 patients developed new PTMC. It is noteworthy that no patients were observed to develop distant metastases during the follow-up period, and no patients had delayed surgery after underwent ablation.

CONCLUSIONS

For patients grappling with MPTMC, TA emerges as an excellent approach for achieving localized tumor control. Nonetheless, achieving favorable outcomes necessitates stringent inclusion criteria and a profound level of expertize.

A combination of risk stratification systems for thyroid nodules and cervical lymph nodes may improve the diagnosis and management of thyroid nodules

Introduction

To assess the performance of the European Thyroid Association Thyroid Imaging and Reporting Data System (EU-TIRADS) and the Korean Thyroid Imaging Reporting and Data System (K-TIRADS), which combine risk stratification systems for thyroid nodules (TN-RSS) and cervical lymph nodes (LN-RSS) in diagnosing malignant and metastatic thyroid cancer in a single referral center.

Methods

We retrospectively analyzed 2,055 consecutive patients who underwent thyroidectomy or fine-needle aspiration (FNA) from January 2021 to December 2022. TNs and LNs were categorized according to the ultrasonography (US) features of EU-TIRADS and K-TIRADS, respectively. The diagnostic performance and postponed malignancy rate (PMR) were compared with those of EU-TIRADS and K-TIRADS. PMR was defined as the number of patients with malignant nodules not recommended for biopsy among patients with cervical LN metastasis.

Results

According to the EU-TIRADS and K-TIRADS, for TN-RSS alone, there were no significant differences in sensitivity, specificity, accuracy, unnecessary FNA rate (UFR), missed malignancy rate (MMR), and PMR between the two TIRADSs (29.0% vs. 28.8%, 50.5% vs. 51.1%, 32.3% vs. 32.2%, 23.6% vs. 23.5%, 88.6% vs. 88.5%, and 54.2% vs. 54.5%, P > 0.05 for all). Combining the LN-RSS increased the diagnostic accuracy (42.7% vs. 32.3% in EU-TIRADS; 38.8% vs. 32.2% in K-TIRADS) and decreased the PMR (54.2% vs. 33.9% in EU-TIRADS; 54.5% vs. 39.3% in K-TIRADS). EU-TIRADS had higher sensitivity and accuracy and lower PMR than K-TIRADS (41.3% vs. 36.7%, 42.7% vs. 38.8%,33.9% vs. 39.3%, P < 0.05 for all).

Conclusions

A combination of TN-RSS and LN-RSS for the management of thyroid nodules may be associated with a reduction in PMR, with enhanced sensitivity and accuracy for thyroid cancers in EU-TIRADS and K-TIRADS. These results may offer a new direction for the detection of aggressive thyroid cancers.

Active surveillance of nodal metastasis in differentiated thyroid carcinoma: a systematic review and meta-analysis

PURPOSE

Cervical lymph nodes (LN) represent the most common site of recurrence in differentiated thyroid cancer (DTC), frequently requiring repeated interventions that contribute to increase morbidity to a usually indolent disease. Data on active surveillance (AS) of nodal metastasis are limited. Therefore, we performed a systematic review and meta-analysis to evaluate AS in nodal metastasis of DTC patients.

METHODS

MEDLINE, EMBASE, and Cochrane databases were searched up to July 2023 for studies including DTC patients with metastatic LN who were followed up with AS. The primary outcome was disease progression, according to the study's definition. Additional outcomes were LN enlargement ≥3 mm, occurrence of new cervical metastasis, and conversion from AS to surgical treatment.

RESULTS

The search identified 375 studies and seven were included, comprising 486 patients with metastatic nodal DTC. Most were female (69.5%) and had papillary thyroid cancer (99.8%). The mean AS follow-up ranged from 28-86 months. Following each study's definition of progression, the pooled incidence was 28% [95% confidence interval (CI), 20-37%]. The pooled incidence of LN growth ≥ 3 mm was 21% [95% CI, 17-25%] and the emergence of new LN sites was 19% [95% CI, 14-25%]. Combining growth of 3 mm and the emergence of new LN criteria, we found an incidence of 26% [95% CI, 20-33%]. The incidence of neck dissection during AS was 18% [95% CI, 12-26%].

CONCLUSIONS

AS seems to be a suitable strategy for selected DTC patients with small nodal disease, avoiding or postponing surgical reintervention.

PROSPERO REGISTRATION

CRD42023438293.

Ethanol ablation of papillary thyroid carcinoma nodal metastases: Long-term outcomes

BACKGROUND

Percutaneous ethanol ablation has emerged as a treatment for recurrent papillary thyroid carcinoma in the lateral neck after compartment-oriented therapeutic lymphadenectomy. However, the safety and utility of percutaneous ethanol ablation as a primary treatment modality for lateral neck metastases remains undefined. We aimed to investigate long-term outcomes of percutaneous ethanol ablation of lateral neck papillary thyroid carcinoma recurrence both with and without prior lymphadenectomy.

METHODS

We conducted a retrospective study of patients with lateral neck papillary thyroid carcinoma treated with percutaneous ethanol ablation from 2013 to 2018. Patient characteristics, disease volume, morbidity, and recurrence (development of new lymphadenopathy within a percutaneous ethanol ablation-treated nodal compartment) were assessed.

RESULTS

We identified 117 patients who underwent percutaneous ethanol ablation for papillary thyroid carcinoma lateral neck metastases-67 (57%) had a prior lateral neck dissection. Median follow-up after percutaneous ethanol ablation was 5.5 years (interquartile range 3.1-7.5). On average, 1.4 lymph nodes (range: 1-6) were treated. Three patients (3%) developed transient nerve-related complications after percutaneous ethanol ablation. Of 15 patients who underwent lateral neck dissection after percutaneous ethanol ablation (including patients undergoing repeat lateral neck dissection), dissection was "difficult" in 8 (53%) (7 of whom had previously undergone lateral neck dissection), and 4 (27%) developed complications (transient nerve dysfunction = 3, lymphatic leak = 1). Thirty-three patients (28%) developed recurrent papillary thyroid carcinoma. No difference in recurrence was seen between patients who did or did not undergo pre-percutaneous ethanol ablation lateral neck dissection (no pre-percutaneous ethanol ablation lateral neck dissection: 24%, pre-percutaneous ethanol ablation lateral neck dissection, 31%; hazard ratio = 1.27, 95% confidence interval 0.62-2.58; P = .514).

CONCLUSION

Percutaneous ethanol ablation may be a safe primary treatment modality for papillary thyroid carcinoma lateral neck nodal recurrence in selected patients with low-volume nodal disease.

Management of radioiodine refractory differentiated thyroid cancer: the Latin American perspective

Radioiodine (RAI) refractory differentiated thyroid cancer is an uncommon and challenging situation that requires a multidisciplinary approach to therapeutic strategies. The definition of RAI-refractoriness is usually a clear situation in specialized centers. However, the right moment for initiation of multikinase inhibitors (MKI), the time and availability for genomic testing, and the possibility of prescribing MKI and selective kinase inhibitors differ worldwide.Latin America (LA) refers to the territories of the world that stretch across two regions: North America (including Central America and the Caribbean) and South America, containing 8.5% of the world's population. In this manuscript, we critically review the current standard approach recommended for patients with RAI refractory differentiated thyroid cancer, emphasizing the challenges faced in LA. To achieve this objective, the Latin American Thyroid Society (LATS) convened a panel of experts from Brazil, Argentina, Chile, and Colombia. Access to MKI compounds continues to be a challenge in all LA countries. This is true not only for MKI but also for the new selective tyrosine kinase inhibitor, which will also require genomic testing, that is not widely available. Thus, as precision medicine advances, significant disparities will be made more evident, and despite efforts to improve coverage and reimbursement, molecular-based precision medicine remains inaccessible to most of the LA population. Efforts should be undertaken to alleviate the discrepancies between the current state-of-the-art care for RAI-refractory differentiated thyroid cancer and the present situation in Latin America.

Wire-guided localization and surgical resection of non-palpable recurrent of thyroid carcinoma: A STROBE-compliant, retrospective cohort study

BACKGROUND

Information on hook-wire guided (HWG) surgery for non-palpable thyroid carcinoma (TC), locoregional-recurrent disease (LRRD) is scarce. We analyze the results of HWG resection compared with the traditional procedure.

METHODS

Cohort study performed between January 2016 and December 2020. Patients with TC and non-palpable LRRD were included. A "Standard cohort", patients with non-HWG resection and "HWG cohort", with HWG resection of LRRD were defined. Surgical morbidity, re-recurrent/progressive disease (RRD), and re-recurrence-free survival (RRFS) were defined.

RESULTS

43 and 23 patients were assigned to the Standard or HWG cohorts, respectively. Complications occurred in 28 % and 17.3 % of cases, in control or HWG cohorts, respectively. HWG cohort, size of primary TC, 131I dose >150 mCi, and thyroglobulin level >1 ng/ml at detection of LRRD were associated with RRD. HWG cohort, thyroglobulin level at LRRD, 131I treatment, and dose were associated with RRFS.

CONCLUSIONS

HWG surgery of non-palpable TC LRRD had improved results regarding surgical morbidity, RRD, and RRFS.

Risk Stratification of Differentiated Thyroid Cancer at King Abdullah Specialized Children's Hospital Endocrinology Clinic in Riyadh, Saudi Arabia

Background Papillary thyroid cancer (PTC), a well-differentiated form of cancer, accounts for the majority of thyroid malignancies, and the incidence of PTC is on the rise. While the rate of PTC recurrence is considered to be low, there are broad spectrums of clinical and biological behavior that can lead to disease recurrence. The American Thyroid Association (ATA) risk stratification system for differentiated thyroid cancer is used as a prognostic tool to guide decision-making and management strategies most likely to achieve a favorable outcome. Aim This study aimed to estimate the prevalence of PTC recurrence in each category of the ATA risk stratification system and determine the appropriate iodine dose to be administered at the King Abdulaziz Medical City Endocrinology Clinic in Riyadh, Saudi Arabia. Methods A cross-sectional retrospective chart review was conducted on adult patients with PTC who underwent thyroidectomy procedures at the King Abdullah Specialized Children's Hospital (KASCH) Endocrinology Clinic in Riyadh between 2015 and 2023. IBM SPSS (Statistical Package for the Social Sciences) version 25 (IBM Corp., Armonk, NY) was used for data analysis. Results Of the 697 patients included in the study, 82.4% were females. About 5% had suffered from PTC recurrence, and 54.4% had low-risk stratification. In addition, more than half (52.1%) had received radioactive iodine (RAI). The recurrence of PTC was significantly associated with age (P = 0.019), ATA risk stratification (P = 0.0001), RAI therapy (P = 0.001), and iodine dosage (P = 0.013). Conclusion Both low PTC recurrence rates and low-risk stratification were observed among the PTC patients. The risk factors relating to PTC recurrence included high-risk stratification, advanced age, RAI therapy, and the dosage of RAI administered.

Neoadjuvant tyrosine kinase inhibitor therapy in locally advanced differentiated thyroid cancer: a single centre case series

OBJECTIVE

Primary surgical resection remains the mainstay of management in locally advanced differentiated thyroid cancer. Tyrosine kinase inhibitors have recently shown promising results in patients with recurrent locally advanced differentiated thyroid cancer. This study discussed four patients with locally advanced differentiated thyroid cancer managed with tyrosine kinase inhibitors used prior to surgery in the 'neoadjuvant' setting.

METHOD

Prospective data collection through a local thyroid database from February 2016 identified four patients with locally advanced differentiated thyroid cancer unsuitable for primary surgical resection commenced on neoadjuvant tyrosine kinase inhibitor therapy.

RESULTS

All cases had T4a disease at presentation. Three cases tolerated tyrosine kinase inhibitor therapy for more than 14 months while the last case failed to tolerate treatment at 1 month. All patients subsequently underwent total thyroidectomy to facilitate adjuvant radioactive iodine treatment. Disease-specific survival remains at 100 per cent currently (range, 29-75 months).

CONCLUSION

Neoadjuvant tyrosine kinase inhibitors in locally advanced differentiated thyroid cancer can be effective in reducing primary tumour extent to potentially facilitate a more limited surgical resection for local disease control.

Validation of Ultrasound and Computed Tomography-Based Risk Stratification System and Biopsy Criteria for Cervical Lymph Nodes in Preoperative Patients With Thyroid Cancer

OBJECTIVE

This study aimed to validate the risk stratification system (RSS) and biopsy criteria for cervical lymph nodes (LNs) proposed by the Korean Society of Thyroid Radiology (KSThR).

MATERIALS AND METHODS

This retrospective study included a consecutive series of preoperative patients with thyroid cancer who underwent LN biopsy, ultrasound (US), and computed tomography (CT) between December 2006 and June 2015. LNs were categorized as probably benign, indeterminate, or suspicious according to the current US- and CT-based RSS and the size thresholds for cervical LN biopsy as suggested by the KSThR. The diagnostic performance and unnecessary biopsy rates were calculated.

RESULTS

A total of 277 LNs (53.1% metastatic) in 228 patients (mean age ± standard deviation, 47.4 years ± 14) were analyzed. In US, the malignancy risks were significantly different among the three categories (all P < 0.001); however, CT-detected probably benign and indeterminate LNs showed similarly low malignancy risks (P = 0.468). The combined US + CT criteria stratified the malignancy risks among the three categories (all P < 0.001) and reduced the proportion of indeterminate LNs (from 20.6% to 14.4%) and the malignancy risk in the indeterminate LNs (from 31.6% to 12.5%) compared with US alone. In all image-based classifications, nodal size did not affect the malignancy risks (short diameter [SD] ≤ 5 mm LNs vs. SD > 5 mm LNs, P ≥ 0.177). The criteria covering only suspicious LNs showed higher specificity and lower unnecessary biopsy rates than the current criteria, while maintaining sensitivity in all imaging modalities.

CONCLUSION

Integrative evaluation of US and CT helps in reducing the proportion of indeterminate LNs and the malignancy risk among them. Nodal size did not affect the malignancy risk of LNs, and the addition of indeterminate LNs to biopsy candidates did not have an advantage in detecting LN metastases in all imaging modalities.

Cut-off Value for Thyroglobulin Washout Concentration in the Detection of Cervical Lymph Node Metastases in Patients after Thyroidectomy Due to Differentiated Thyroid Cancer

The aim of this study was to establish the cut-off value for the thyroglobulin (Tg) concentration in washout fluid from fine needle aspiration biopsy (FNA-Tg) in the detection of cervical lymph node metastases of differentiated thyroid cancer (DTC). We evaluated the validity and clinical utility of fine needle aspiration biopsy cytology (FNAB-C), FNA-Tg, and the combined method in detecting DTC recurrences. The study included 82 patients after the total thyroidectomy and elective and, in some cases, also selective cervical lymphadenectomy. The majority of patients also underwent subsequent 131I ablative therapy. The patients presented with 1-6 enlarged and/or ultrasonographically suspicious cervical lymph nodes. One to four aspirates of each lymph node were taken, with a total of 297 samples. An FNA-Tg of 4.34 ng/mL was established as the cut-off value for detecting cervical lymph node DTC metastases for the IRMA Brahms DYNO test, Tg-S. FNAB-C is highly specific (91-99%) but not sensitive enough (53-69%) to be used as a standalone method in the detection of cervical lymph node metastases. FNA-Tg is more sensitive (91%), but caution should be taken when selecting patients for surgery with an FNA-Tg higher than the established cut-off value but lower than the serum Tg concentration. To select patients for lymphadenectomy, we recommend using the combined method (FNAB-C and FNA-Tg) with a sensitivity of 96% and specificity of up to 97%. More than one sample should be taken with each fine needle aspiration biopsy (FNAB) to obtain a representative set of samples.

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

AIMS

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Modified dynamic risk stratification system further predicts individual outcome in patients with intermediate-risk papillary thyroid cancer

OBJECTIVE

We assessed the contribution of initial treatment response to further refining prediction of individual outcomes in intermediate-risk papillary thyroid cancer (PTC) on the American Thyroid Association (ATA) risk stratification system. Dynamic risk stratification (DRS) as originally proposed by Tuttle et al. in 2010 was modified to also include serum antithyroglobulin antibodies (TgAb) as a surrogate marker of the likelihood of persistent disease, specifically in patients with thyroglobulin assay interference by TgAb.

METHODS

Three hundred and seventy-three patients with ATA intermediate-risk PTC were enrolled retrospectively upon reviewing medical records. Patients were followed at the National Cancer Institute in Bogota, Colombia after being treated with total thyroidectomy and I-131 therapy between 2009 and 2013. Best response to initial therapy was classified as excellent, indeterminate, biochemically incomplete or structurally incomplete. Final disease status after a median follow-up of 7.1 years was classified as no evidence of disease (NED), indeterminate, or persistent disease (either biochemically or structurally). The rate of recurrence was determined in excellent responders.

RESULTS

Excellent response was achieved by 164 patients (43.9%). At a median follow-up of 42 months, 19 (11.6%) had experienced recurrence. 87.4% of initially excellent responders available at the final checkpoint were NED, compared to 28% of those with biochemically or structurally incomplete response and to 60.2% of all ATA intermediate-risk PTC patients in our cohort.

CONCLUSIONS

Modified DRS further predicted individual outcomes in intermediate-risk PTC, potentially allowing ongoing management to be tailored accordingly.

Diagnosis of cervical lymph node metastasis with thyroid carcinoma by deep learning application to CT images

Introduction

The incidence of thyroid diseases has increased in recent years, and cervical lymph node metastasis (LNM) is considered an important risk factor for locoregional recurrence. This study aims to develop a deep learning-based computer-aided diagnosis (CAD) method to diagnose cervical LNM with thyroid carcinoma on computed tomography (CT) images.

Methods

A new deep learning framework guided by the analysis of CT data for automated detection and classification of LNs on CT images is proposed. The presented CAD system consists of two stages. First, an improved region-based detection network is designed to learn pyramidal features for detecting small nodes at different feature scales. The region proposals are constrained by the prior knowledge of the size and shape distributions of real nodes. Then, a residual network with an attention module is proposed to perform the classification of LNs. The attention module helps to classify LNs in the fine-grained domain, improving the whole classification network performance.

Results

A total of 574 axial CT images (including 676 lymph nodes: 103 benign and 573 malignant lymph nodes) were retrieved from 196 patients who underwent CT for surgical planning. For detection, the data set was randomly subdivided into a training set (70%) and a testing set (30%), where each CT image was expanded to 20 images by rotation, mirror image, changing brightness, and Gaussian noise. The extended data set included 11,480 CT images. The proposed detection method outperformed three other detection architectures (average precision of 80.3%). For classification, ROI of lymph node metastasis labeled by radiologists were used to train the classification network. The 676 lymph nodes were randomly divided into 70% of the training set (73 benign and 401 malignant lymph nodes) and 30% of the test set (30 benign and 172 malignant lymph nodes). The classification method showed superior performance over other state-of-the-art methods with an accuracy of 96%, true positive and negative rates of 98.8 and 80%, respectively. It outperformed radiologists with an area under the curve of 0.894.

Discussion

The extensive experiments verify the high efficiency of the proposed method. It is considered instrumental in a clinical setting to diagnose cervical LNM with thyroid carcinoma using preoperative CT images. The future research can consider adding radiologists' experience and domain knowledge into the deep-learning based CAD method to make it more clinically significant.

Conclusion

The extensive experiments verify the high efficiency of the proposed method. It is considered instrumental in a clinical setting to diagnose cervical LNM with thyroid carcinoma using preoperative CT images.

Cervical lymph node metastasis prediction of postoperative papillary thyroid carcinoma before 131I therapy based on clinical and ultrasound characteristics

BACKGROUND

The status of lymph nodes is crucial to determine the dose of radioiodine-131(¹³¹I) for postoperative papillary thyroid carcinoma (PTC). We aimed to develop a nomogram for predicting residual and recurrent cervical lymph node metastasis (CLNM) in postoperative PTC before ¹³¹I therapy.

METHOD

Data from 612 postoperative PTC patients who underwent ¹³¹I therapy from May 2019 to December 2020 were retrospectively analyzed. Clinical and ultrasound features were collected. Univariate and multivariate logistic regression analyses were performed to determine the risk factors of CLNM. Receiver operating characteristic (ROC) analysis was used to weigh the discrimination of prediction models. To generate nomograms, models with high area under the curves (AUC) were selected. Bootstrap internal validation, calibration curves and decision curves were used to assess the prediction model's discrimination, calibration, and clinical usefulness.

RESULTS

A total of 18.79% (115/612) of postoperative PTC patients had CLNM. Univariate logistic regression analysis found serum thyroglobulin (Tg), serum thyroglobulin antibodies (TgAb), overall ultrasound diagnosis and seven ultrasound features (aspect transverse ratio, cystic change, microcalcification, mass hyperecho, echogenicity, lymphatic hilum structure and vascularity) were significantly associated with CLNM. Multivariate analysis revealed higher Tg, higher TgAb, positive overall ultrasound and ultrasound features such as aspect transverse ratio ≥ 2, microcalcification, heterogeneous echogenicity, absence of lymphatic hilum structure and abundant vascularity were independent risk factors for CLNM. ROC analysis showed the use of Tg and TgAb combined with ultrasound (AUC = 0.903 for "Tg+TgAb+Overall ultrasound" model, AUC = 0.921 for "Tg+TgAb+Seven ultrasound features" model) was superior to any single variant. Nomograms constructed for the above two models were validated internally and the C-index were 0.899 and 0.914, respectively. Calibration curves showed satisfied discrimination and calibration of the two nomograms. DCA also proved that the two nomograms were clinically useful.

CONCLUSION

Through the two accurate and easy-to-use nomograms, the possibility of CLNM can be objectively quantified before ¹³¹I therapy. Clinicians can use the nomograms to evaluate the status of lymph nodes in postoperative PTC patients and consider a higher dose of ¹³¹I for those with high scores.

The outcomes and prognostic factors of patients who underwent reoperation for persistent/recurrent papillary thyroid carcinoma

BACKGROUND

While the most suitable approach for treating persistent/recurrent papillary thyroid carcinoma (PTC) remains controversial, reoperation may be considered an effective method. The efficacy of reoperation in patients with locoregional persistent/recurrent PTC, especially those with unsatisfactory radioactive iodine (RAI) ablation results, is still uncertain. This study aimed to clarify the clinical management strategies for locoregional persistent/recurrent PTC and to explore factors that may affect long-term patient outcomes after reoperation.

METHODS

In total, 124 patients who initially underwent thyroidectomy and variable extents of RAI therapy and finally received reoperation for locoregionally persistent/recurrent PTC were included. The parameters associated with recurrence-free survival (RFS) were analysed using a Cox proportional hazards model.

RESULTS

Overall, 124 patients presented with structural disease after initial therapy and underwent secondary surgical resection, of whom 32 patients developed further structural disease during follow-up after reoperation. At the time of reoperation, metastatic lymph nodes with extranodal extension (P = 0.023) and high unstimulated thyroglobulin (unstim-Tg) levels after reoperation (post-reop) (P = 0.001) were independent prognostic factors for RFS. Neither RAI avidity nor the frequency and dose of RAI therapies before reoperation affected RFS.

CONCLUSIONS

Reoperation is an ideal clinical treatment strategy for structural locoregional persistent/recurrent PTC, and repeated empirical RAI therapies performed prior to reoperation may not contribute to the long-term outcomes of persistent/recurrent PTC patients. Metastatic lymph nodes with extranodal extension and post-reop unstim-Tg > 10.1 ng/mL may predict a poor prognosis.

Active Surveillance of Small Metastatic Lymph Nodes as an Alternative to Surgery in Selected Patients with Low-Risk Papillary Thyroid Cancer: A Retrospective Cohort Study

Background: It has been suggested that small metastatic lymph nodes (LNs) detected after initial surgery in patients with differentiated thyroid cancer (DTC) can be managed with active surveillance (AS). However, there is still concern regarding the clinical outcomes of these patients. The main aims of our study were as follows: (1) to assess the frequency of growth and the need of additional treatment in a group of patients with LN recurrences selected for AS, and (2) to determine predictive factors of LN progression. Methods: We retrospectively reviewed 856 clinical records from our DTC patient's database (May 2010 to January 2022). Eighty patients had suspicious cervical LNs on consecutive ultrasound (US) after initial surgery, but we included 50 patients with cytological confirmation of metastatic disease and at least 12 months follow-up. Exclusion criteria were as follows: any LN ≥2 cm or multiple LNs ≥1.5 cm in size, proximity to vital structures, PET-positive disease (standard uptake value ≥5), aggressive histology, and distant metastasis. Patients were followed with thyroglobulin (Tg) and thyroglobulin antibodies measurements on suppressive therapy and neck US every 6-12 months. LN growth was defined as an increase of ≥3 mm in any of its diameters. Results: A total of 50 patients had a median age of 41 years (range, 18-75). Most patients were women (80%) and had classical papillary thyroid cancer (86%). The mean size of the LNs was 10.1 ± 4.4 mm. After a median follow-up of 29 months (range, 12-144), 12 patients (24%) had an increase in size of the metastatic LN, 7 (58%) of whom were surgically removed. None of these seven patients had a structural incomplete response at the end of follow-up. The only variable that predicted an increase in LN size was a rise in Tg levels ≥0.5 ng/mL (p = 0.016). Based on a multivariate analysis, patients with increase in Tg levels ≥0.5 ng/mL had a significantly higher chance of developing LN growth (odds ratio [OR] 16.2 [confidence interval, CI 1.5-120.2], p = 0.020). The median progression-free survival rate was 6.6 years [CI 5.6-9.5]. Conclusion: AS of small LNs could be a feasible alternative to immediate surgery in properly selected patients.

Real-time intraoperative near-infrared autofluorescence imaging to locate the parathyroid glands: A preliminary report

Identification and localization of parathyroid glands (PGs) remains a challenge for surgeons. The aim of this study was to evaluate the efficiency of intraoperative near-infrared autofluorescence (NIRAF) imaging to detect PGs in thyroid and parathyroid diseases. Seventy-six patients undergoing surgery for thyroid or parathyroid diseases between July 9, 2020 and August 20, 2021 were retrospectively analyzed. Intraoperative carbon nanoparticle (CN) negative imaging and handheld NIRAF imaging were successively performed for each patient. Of 206 PGs that needed to be identified for surgery, 162 were identified by NIRAF imaging, with a theoretical rate of identification of 78.64%. This was higher than the rate of identification with CN negative imaging, which was 75.73%. The number of PGs identified by NIRAF imaging and CN negative imaging did not differ significantly in either total thyroidectomy or thyroid lobectomy. In addition, the autofluorescence (AF) intensity of secondary parathyroid adenoma was weaker than that of normal PGs. NIRAF imaging is potentially a more efficient tool for identification of PGs than CN negative imaging, with a shorter learning curve and lower risk. It may not be well-suited to secondary hyperthyroidism or adenoma, but it was more efficient at identifying excised specimens than visual identification by a surgeon.

Lymph Node Metastases Identified at the Post-Ablation 131I SPECT/CT Scan Is a Prognostic Factor of Intermediate-Risk Papillary Thyroid Cancer

The intermediate-risk category of papillary thyroid cancer (PTC) comprises heterogeneous patients within a wide range of stages and varied care management. Understanding the risk features of recurrence observed after the initial therapy should be emphasized. We aimed to evaluate the prognostic significance of radioactive iodine-avid lymph nodes observed during the initial treatment of patients with PTC that were considered to be at intermediate risk. Data on patients with intermediate-risk PTC treated from 2012 to 2018 were retrospectively reviewed. Post-therapeutic SPECT/CT (Rx SPECT/CT) was evaluated in the enrolled patients. The clinical, pathologic, and incidence of radioiodine-avid (RAI-avid) lymph node metastasis (mLN) on Rx SPECT/CT were reviewed, and risk factors related to recurrent disease were analyzed. After a median follow-up of 37.26 (30.90, 46.33) months, structural persistent/recurrent disease was detected in 9.81% (36/367) of patients with intermediate-risk tumors. The incidence of recurrence was higher in patients who demonstrated RAI-avid mLN after the initial therapy than in those who did not (p < 0.001). In a multivariate Cox proportional hazard regression analysis, RAI-avid mLN appeared to be a robust risk factor for recurrent disease after the initial therapy (HR: 8.967, 95% CI: 3.433−23.421, p = 0.000). RAI-avid mLN is a significant risk factor for recurrent intermediate-risk PTC after the initial treatment.

Radiomics Profiling Identifies the Value of CT Features for the Preoperative Evaluation of Lymph Node Metastasis in Papillary Thyroid Carcinoma

Background: The aim of this study was to identify the increased value of integrating computed tomography (CT) radiomics analysis with the radiologists’ diagnosis and clinical factors to preoperatively diagnose cervical lymph node metastasis (LNM) in papillary thyroid carcinoma (PTC) patients. Methods: A total of 178 PTC patients were randomly divided into a training (n = 125) and a test cohort (n = 53) with a 7:3 ratio. A total of 2553 radiomic features were extracted from noncontrast, arterial contrast-enhanced and venous contrast-enhanced CT images of each patient. Principal component analysis (PCA) and Pearson’s correlation coefficient (PCC) were used for feature selection. Logistic regression was employed to build clinical–radiological, radiomics and combined models. A nomogram was developed by combining the radiomics features, CT-reported lymph node status and clinical factors. Results: The radiomics model showed a predictive performance similar to that of the clinical–radiological model, with similar areas under the curve (AUC) and accuracy (ACC). The combined model showed an optimal predictive performance in both the training (AUC, 0.868; ACC, 86.83%) and test cohorts (AUC, 0.878; ACC, 83.02%). Decision curve analysis demonstrated that the combined model has good clinical application value. Conclusions: Embedding CT radiomics into the clinical diagnostic process improved the diagnostic accuracy. The developed nomogram provides a potential noninvasive tool for LNM evaluation in PTC patients.

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

Simple Summary

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

Abstract

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

State of the Art in the Current Management and Future Directions of Targeted Therapy for Differentiated Thyroid Cancer

Two-thirds of differentiated thyroid cancer (DTC) patients with distant metastases would be classified as radioactive iodine-refractory (RAIR-DTC), evolving into a poor outcome. Recent advances underlying DTC molecular mechanisms have shifted the therapy focus from the standard approach to targeting specific genetic dysregulations. Lenvatinib and sorafenib are first-line, multitargeted tyrosine kinase inhibitors (TKIs) approved to treat advanced, progressive RAIR-DTC. However, other anti-angiogenic drugs, including single targeted TKIs, are currently being evaluated as alternative or salvage therapy after the failure of first-line TKIs. Combinatorial therapy of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) signalling cascade inhibitors has become a highly advocated strategy to improve the low efficiency of the single agent treatment. Recent studies pointed out targetable alternative pathways to overcome the resistance to MAPK and PI3K pathways’ inhibitors. Because radioiodine resistance originates in DTC loss of differentiation, redifferentiation therapies are currently being explored for efficacy. The present review will summarize the conventional management of DTC, the first-line and alternative TKIs in RAIR-DTC, and the approaches that seek to overcome the resistance to MAPK and PI3K pathways’ inhibitors. We also aim to emphasize the latest achievements in the research of redifferentiation therapy, immunotherapy, and agents targeting gene rearrangements in advanced DTC.

Revision Thyroid Surgery

The incidence of recurrence in well-differentiated thyroid malignancies range from 10 to 30%. It is estimated that about 31-46% of patients with differentiated thyroid cancer will have the persistent disease and 1.2-6.8% will have structural recurrences during post-operative monitoring, depending on the initial therapy and prognostic variables. It is challenging to decide on treatment versus active monitoring following repeated or persistent tumour detection. The biological factors of the tumour and the patient guide us in the overall decision-making. Revision thyroid surgery is technically challenging. The morbidity encountered during the revision surgery is related to the anatomy of the region undergoing dissection, the degree of fibrosis and scarring from prior surgery and the operating surgeon's experience. Successful comprehensive management of revision thyroid surgery needs a multi-disciplinary approach. This review article highlights the definition, indications for revision surgery, identification of recurrent disease, management of parathyroid and recurrent laryngeal nerves with neuromonitoring.

Imaging of Cervical Lymph Nodes in Thyroid Cancer: Ultrasound and Computed Tomography

Sonographic evaluation of cervical lymph nodes in patients with thyroid malignancy is important both for preoperative staging and for post-treatment surveillance, and contrast-enhanced computed tomography plays a complementary role. Knowledge of anatomy and surgical approaches, combined with an understanding of the various imaging features that distinguish malignant from benign lymph nodes, allows for accurate staging, thereby enabling complete surgical initial resection.

Radiofrequency ablation versus total thyroidectomy in patients with papillary thyroid microcarcinoma located in the isthmus: a retrospective cohort study

OBJECTIVE

This retrospective study aimed to examine the benefits and complications of radiofrequency ablation (RFA) in patients with papillary thyroid microcarcinoma (PTMC) in the isthmus.

METHODS

This retrospective study included patients with PTMC in the isthmus and treated at the Chinese People's Liberation Army hospital from 05/2014 to 05/2018. The patients were divided into the RFA and total thyroidectomy (TT) groups. The outcomes were operation-related complications, rate of recurrence, metastasis rate, and thyroid carcinoma-specific questionnaire of quality of life (THYCA-QOL).

RESULTS

Among 218 patients, 115 patients underwent RFA, and 103 underwent TT. The rates of disappearance of the ablation zone at 1, 3, 6, 12, and 18 months after RFA were 0.8% (1/115), 10.4% (12/115), 51.3% (59/115), 90.4% (104/115), and 100% (115/115), respectively. Surgical time, blood loss, hospital stays, and treatment costs were higher with TT than with RFA (all p < 0.001). The final THYCA-QOL score of the RFA group was significantly higher than in the TT group (p < 0.001). Minor pain at the operation site was seen in all patients in the RFA group. No distant metastasis was detected in all patients, but one patient in the RFA group had a recurrence after 6 months. The final THYCA-QOL score of the RFA group was significantly lower than in the TT group (p < 0.001).

CONCLUSION

These results suggest that RFA for PTMC in the isthmus had similar outcomes than TT. It will have to be confirmed in future studies.

The Growth Kinetics of Collision Nodal Metastasis from Medullary and Papillary Thyroid Carcinomas: A Case Report

INTRODUCTION

The collision of medullary (MTC) and papillary thyroid carcinoma (PTC) in the same cervical lymph node can occur, but its growth kinetics has not been reported.

CASE PRESENTATION

We report a 27-year-old male patient who had collision nodal metastases from PTC and sporadic MTC in the central compartment. This was treated with total thyroidectomy and central neck dissection. The collision nodal metastasis persisted and presented with a single sonographically enlarging central compartmental lymph node postoperatively. The volume of the collision nodal metastasis increased from 226 to 507 mm³ over the first 8 months, from 507 to 572 mm³ over the next 6 months, and from 572 to 762 mm³ over the next 31 months. The calcitonin and carcinoembryonic antigen (CEA) fluctuated in the first 19 months followed by a steady increase at a doubling time of 1.97 and 8.42 years, respectively. Unstimulated thyroglobulin remained at 0.2 ng/mL or lower during the same period while thyrotropin (TSH) was not suppressed. Revision central neck dissection performed 4.5 years later resulted in undetectable serum calcitonin, CEA of 2 ng/mL, and thyroglobulin of 0.1 ng/mL from a preoperative calcitonin of 212 ng/L, CEA of 10 ng/mL, and thyroglobulin of 0.2 ng/mL. Further structural imaging 13.5 months later revealed no evidence of disease.

DISCUSSION

The growth kinetics of collision nodal metastasis from PTC and MTC can be similar to conventional PTC and MTC. Furthermore, the growth rate of such collision nodal metastases can be slow. Guided by tumor marker doubling time and regular structural imaging, surgical salvage performed after a period of active surveillance may still result in biochemical and structural remission.

Five-year follow-up results of thermal ablation for low-risk papillary thyroid microcarcinomas: systematic review and meta-analysis

OBJECTIVES

Confidence in long-term treatment results of thermal ablation for papillary thyroid microcarcinoma (PTMC) is required in comparison with active surveillance. The objective of this meta-analysis is to report 5-year follow-up results of thermal ablation for PTMC.

METHODS

Ovid MEDLINE and EMBASE databases were searched through May 30, 2020, for studies reporting outcomes in patients with PTMC treated with thermal ablation and followed up for at least 5 years. Data were extracted and methodological quality was assessed independently by two radiologists according to the PRISMA guidelines.

RESULTS

Three studies, involving 207 patients with 219 PTMCs, met the inclusion criteria through database searches. None of these patients experienced local tumor recurrence, lymph node metastasis, or distant metastasis or underwent delayed surgery during a mean pooled 67.8-month follow-up. Five new tumors appeared in the remaining thyroid gland of four patients, with four of these tumors successfully treated by repeat thermal ablation. The pooled mean major complication rate was 1.2%, with no patient experiencing life-threatening or delayed complications.

CONCLUSIONS

Thermal ablation is an excellent local tumor control method in patients with low-risk PTMC, with low major complication rates at 5 years.

KEY POINTS

• No local tumor recurrence, lymph node metastasis, or distant metastasis was noted by thermal ablation during follow-up of 5 years and none underwent delayed surgery. • The pooled mean major complication rate was 1.2%.

Role of Sonographic Characteristics of Thyroid Bed Lesions Identified Following Thyroidectomy in the Diagnosis or Exclusion of Recurrent Cancer

Background US of the thyroid bed in patients with thyroid cancer often depicts small lesions, but it is unclear whether US characteristics of lesions can help predict cancer recurrence. Purpose To determine whether size or US features of lesions in the thyroid bed after thyroidectomy in conjunction with clinical features can help predict thyroid cancer recurrence. Materials and Methods With use of a US reporting database, all patients imaged between July 2006 and June 2016 with an indication of post-thyroidectomy follow-up were retrospectively identified. Recorded data included patient demographic characteristics; date of thyroidectomy; thyroid cancer type; presence, size, and US characteristics of thyroid bed lesions; and results of fine-needle aspiration (FNA). Images were reviewed for lesions that underwent FNA. The Fisher exact test was used for analysis. Results A total of 1885 patients (mean age ± standard deviation, 48 years ± 15; 1493 female patients) underwent 5732 US examinations. Most patients (1541 of 1885 [82%]) had papillary cancer. Overall, 3163 thyroid bed lesions were reported in 5732 US examinations (40.4%). More than half of these lesions (1860 of 3163 [58.8%]) had a maximum measurement of 6 mm or greater. FNA was performed in 144 of the 3163 lesions (4.6%), of which 61 (42.4%) were malignant, 33 (22.9%) were benign, and 50 (34.7%) were nondiagnostic. Five nondiagnostic lesions eventually proved malignant. Only the presence of punctate echogenicities in the lesion (28 of 61 malignant lesions [45.9%]; three of 33 benign lesions [9%]; 12 of 50 nondiagnostic lesions [24%]; P < .001) or the history of positive lymph nodes at thyroidectomy (44 of 61 malignant lesions [72.1%]; 10 of 33 benign lesions [30%]; 19 of 50 nondiagnostic lesions [38%]; P < .001) were associated with malignancy. Of 3019 thyroid bed lesions that did not undergo FNA, three were malignant and 2248 showed no growth at follow-up US ranging from 6 months to 10 years and are presumed benign. Of the 1303 lesions smaller than 6 mm, only two (0.2%) were malignant. Conclusion Small lesions are commonly found in the thyroid bed after thyroidectomy, and most are likely to be benign. Lesions smaller than 6 mm with no punctate echogenicities had a minimal risk for malignancy. © RSNA, 2021 See also the editorial by Grant and Malhi in this issue.

A comparison of the efficiency of diagnostic ultrasound and magnetic resonance imaging of cervical lymph nodes in papillary thyroid carcinoma

OBJECTIVE

To compare and evaluate diagnostic capabilities of preoperative ultrasonography (US) and magnetic resonance imaging (MRI) in the cervical lymph nodes of patients with papillary thyroid cancer.

METHODS

A retrospective dataset involving 156 patients who had undergone thyroidectomy and preoperative US and MRI was assembled. Among these, 69 had cervical lymph node metastasis and 87 did not. At least four radiologists unilaterally and spontaneously investigated the US and MRI attributes of the cervical lymph nodes. The efficiency of diagnostic imaging for cervical lymph nodes, including their true-positive rate or sensitivity, true-negative rate or specificity, positive predictive value, negative predictive value, and predictive accuracy were analysed and assessed.

RESULTS

In the assessment of cervical lymph node metastases of papillary thyroid cancer, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of diagnostic US vs. MRI were 58.0% vs. 79.7%, 69.0% vs. 83.9%, 59.7% vs. 79.7%, 67.4% vs. 83.9%, and 64.1% vs. 82.1%, respectively. The accuracy consistency of the two imaging modalities was 83.5%.

CONCLUSIONS

MRI is more effective than US in diagnosing and assessing cervical lymph node metastases of papillary thyroid cancer.

Computed Tomography-Based Radiomics Model to Predict Central Cervical Lymph Node Metastases in Papillary Thyroid Carcinoma: A Multicenter Study

OBJECTIVES

This study aimed to develop a computed tomography (CT)-based radiomics model to predict central lymph node metastases (CLNM) preoperatively in patients with papillary thyroid carcinoma (PTC).

METHODS

In this retrospective study, 678 patients with PTC were enrolled from Yantai Yuhuangding Hot3spital (n=605) and the Affiliated Hospital of Binzhou Medical University (n=73) within August 2010 to December 2020. The patients were randomly divided into a training set (n=423), an internal test set (n=182), and an external test set (n=73). Radiomics features of each patient were extracted from preoperative plain scan and contrast-enhanced CT images (arterial and venous phases). One-way analysis of variance (ANOVA) and least absolute shrinkage and selection operator algorithm were used for feature selection. The K-nearest neighbor, logistics regression, decision tree, linear-support vector machine (linear-SVM), Gaussian-SVM, and polynomial-SVM algorithms were used to establish radiomics models for CLNM prediction. The clinical risk factors were selected by ANOVA and multivariate logistic regression. Incorporated with clinical risk factors, a combined radiomics model was established for the preoperative prediction of CLNM in patients with PTCs. The performance of the combined radiomics model was evaluated using the receiver operating characteristic (ROC) and calibration curves in the training and test sets. The clinical usefulness was evaluated through decision curve analysis (DCA).

RESULTS

A total of 4227 radiomic features were extracted from the CT images of each patient, and 14 non-zero coefficient features associated with CLNM were selected. Four clinical variables (sex, age, tumor diameter, and CT-reported lymph node status) were significantly associated with CLNM. Linear-SVM led to the best prediction model, which incorporated radiomic features and clinical risk factors. Areas under the ROC curves of 0.747 (95% confidence interval [CI] 0.706-0.782), 0.710 (95% CI 0.634-0.786), and 0.764 (95% CI 0.654-0.875) were obtained in the training, internal, and external test sets, respectively. The linear-SVM algorithm also showed better sensitivity (0.702 [95% CI 0.600-0.790] vs. 0.477 [95% CI 0.409-0.545]) and accuracy (0.670 [95% CI 0.600-0.738] vs. 0.642 [95% CI 0.569-0.712]) than an experienced radiologist in the internal test set in the combined radiomics model. The calibration plot reflected a favorable agreement between the actual and estimated probabilities of CLNM. The DCA indicated the clinical usefulness of the combined radiomics model.

CONCLUSION

The combined radiomics model is a non-invasive preoperative tool that incorporates radiomic features and clinical risk factors to predict CLNM in patients with PTC.

Long-Term Follow-Up Results of Ultrasound-Guided Radiofrequency Ablation for Low-Risk Papillary Thyroid Microcarcinoma: More Than 5-Year Follow-Up for 84 Tumors

Background: Despite reports describing favorable short-term results for thermal ablation of thyroid cancer, there remains a need to evaluate long-term results because of its indolent characteristics. The purpose of this study was to evaluate the long-term efficacy and safety of ultrasound (US)-guided radiofrequency ablation (RFA) for low-risk papillary thyroid microcarcinoma (PTMC) over a follow-up period of more than five years. Methods: From a cohort of patients under surveillance after US-guided RFA for primary low-risk PTMC, those with a record of follow-up data of more than five years were selected for this study. Before RFA, all patients underwent US and computed tomography to evaluate the PTMC and the presence of neck metastasis. RFA was performed using thyroid-dedicated electrodes. Follow-up US was performed 6 and 12 months after initial RFA, and then every 12 months. The status of ablated tumors was evaluated according to volume reduction, local tumor progression, newly developed cancers, lymph node (LN) or distant metastasis, and delayed surgery during follow-up. Complications during the procedure and follow-up period were evaluated. Results: A total of 84 nodules from 74 patients were included in this study. All patients tolerated RFA, and the mean follow-up duration was 72 months. After RFA, complete disappearance rates of 98.8% and 100% were achieved at 24 and 60-month follow-up, respectively. Additional ablations were performed in 13 of 84 tumors. The mean number of RFA sessions was 1.2. There were four newly developed cancers in three patients, and these were also treated with RFA and completely disappeared. During the follow-up period, there was no local tumor progression, no LN or distant metastasis, and no patients underwent delayed surgery. The major complication rate was 1.4% (1/74), and there was no delayed complication or procedure-related death. Conclusions: RFA is effective for treating low-risk PTMC patients, without occurrence of local tumor progression, LN or distant metastasis, delayed complications, procedure-related death, or delayed surgery over more than five years of follow-up.

Investigating the demographic characteristics and pathological manifestations of thyroid Cancer during the last two decades (1997-2017) in patients referred to Baqiyatallah hospital, Tehran, Iran

Background & Objective

Thyroid cancer is among the most common endocrine cancers, and its incidence in our country is in progress over the past decades. This aggravates the necessity to evaluate the changes in thyroid cancer.

Materials & methods

Through accessing the information of the records of all patients with a diagnosis of thyroid cancer between 1996 and 2017, the present study was conducted at Baqiyatallah Hospital (Tehran, Iran) according to scientific criteria. After the diagnosis, most of them also underwent surgery and were evaluated in terms of the rate of the involvement and the type of thyroid cancer, and the pathology report was recorded in their records. Information about the intended patients such as age, gender, pathologic type of cancer, associated with the patient (except thyroid cancer), and history of radiation to the patient were recorded in a standard form and subjected to statistical analysis. Demographic changes and pathological manifestations of cancers in the two decades (1997-2007) and (2007-2017) were compared. But comparisons have been made over five years.

Results

The incidence of thyroid cancer, especially papillary thyroid cancer type, was increasing at an early age, and the incidence of tumor size measuring 2-4 cm was rising. But the incidence of tumor sizes less than one centimeter declined. The amount of vascular and capsule involvement was about 3 times, and lymph node involvement was nearly 2 times. The increasing incidence of 2-4 cm tumor size in the age group of 20-50 years was more than other age groups.

Conclusion

The incidence of thyroid cancer was increasing at an early age, and the enhancement of papillary thyroid type was higher than other types. As well as, in this study, it was found that the incidence of 2-4 cm tumor sizes was rising.

Unusual locations for differentiated thyroid cancer nodal metastasis

Lymph node metastasis is common in differentiated thyroid cancer especially papillary thyroid cancer. Presence of lymph node metastasis does not have an impact on survival in younger patients. Therapeutic central and lateral neck dissection in the presence of clinically or radiologically evident lymph nodes has resulted in good overall survival. However, disease persistence in the lymph node/early recurrences may be seen in patients owing to lymph nodes that may be missed during the initial neck dissection. These observed locations are retropharyngeal and parapharyngeal nodal location, retro carotid location, sublingual, axillary, and intraparotid locations, supraclavicular and superficial to the sternothyroid muscle. We aim to highlight these locations with the goal to minimize persistence or early recurrence of disease at these locations.

Selective Neck Dissection Guided by a Radioactive I125 Seed for Papillary Thyroid Carcinoma Recurrence

Lymph nodes are the most common place of recurrence of papillary thyroid cancer, and surgery can be considered a therapeutic option. The risks of surgery increase with every intervention. We present 3 cases of cervical non palpable thyroid cancer recurrence managed with I125 seed radioguided cervical dissection from 2017 to 2019. Two of the cases had already a thyroidectomy and central compartment lymphadenectomy performed. The seed was placed guided by US on the lesion and its position was confirmed afterwards. The target was successfully localized in 100% of cases. There was no post surgery complications. There was no evidence of recurrence with a mean follow up of 15 months. Radioguided surgery using I125 seed it is a save technique and it offers a precise localization of the non palpable thyroid cancer recurrence.

The American Association of Endocrine Surgeons Guidelines for the Definitive Surgical Management of Thyroid Disease in Adults

OBJECTIVE

To develop evidence-based recommendations for safe, effective, and appropriate thyroidectomy.

BACKGROUND

Surgical management of thyroid disease has evolved considerably over several decades leading to variability in rendered care. Over 100,000 thyroid operations are performed annually in the US.

METHODS

The medical literature from 1/1/1985 to 11/9/2018 was reviewed by a panel of 19 experts in thyroid disorders representing multiple disciplines. The authors used the best available evidence to construct surgical management recommendations. Levels of evidence were determined using the American College of Physicians grading system, and management recommendations were discussed to consensus. Members of the American Association of Endocrine Surgeons reviewed and commented on preliminary drafts of the content.

RESULTS

These clinical guidelines analyze the indications for thyroidectomy as well as its definitions, technique, morbidity, and outcomes. Specific topics include Pathogenesis and Epidemiology, Initial Evaluation, Imaging, Fine Needle Aspiration Biopsy Diagnosis, Molecular Testing, Indications, Extent and Outcomes of Surgery, Preoperative Care, Initial Thyroidectomy, Perioperative Tissue Diagnosis, Nodal Dissection, Concurrent Parathyroidectomy, Hyperthyroid Conditions, Goiter, Adjuncts and Approaches to Thyroidectomy, Laryngology, Familial Thyroid Cancer, Postoperative Care and Complications, Cancer Management, and Reoperation.

CONCLUSIONS

Evidence-based guidelines were created to assist clinicians in the optimal surgical management of thyroid disease.

Diagnostic performance of MRI to detect metastatic cervical lymph nodes in patients with thyroid cancer: a systematic review and meta-analysis

AIM

To evaluate the diagnostic performance of magnetic resonance imaging (MRI) in the diagnosis of metastatic cervical lymph nodes.

MATERIALS AND METHODS

Ovid-MEDLINE and EMBASE databases were searched up until 12 June 2018. Eleven articles were included in the qualitative systematic review and nine of the 11 in the quantitative analysis. Two radiologists independently performed data extraction and methodological quality assessment using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. A qualitative systematic review and quantitative analysis were performed, followed by a meta-regression analysis to determine factors causing heterogeneity.

RESULTS

The pooled sensitivity and specificity in the diagnosis of metastatic cervical lymph nodes were 80% (95% confidence interval [CI]: 68-88%) and 85% (95% CI: 63-95%), respectively. The sensitivity and false-positive rate (correlation coefficient, 0.655) showed a positive correlation due to a threshold effect, which was responsible for heterogeneity across the studies, as indicated by a Q-test (p<0.01) and Higgins I² statistic (sensitivity, I²=90.11%; specificity, I²=92.49%). In the meta-regression analysis, fat-suppressed imaging, and the analysis method were significant factors influencing the heterogeneity in diagnostic performance.

CONCLUSIONS

MRI shows moderate diagnostic performance in the diagnosis of metastatic lymph nodes in patients with thyroid cancer in the neck. MRI may be an optional or complementary imaging method to ultrasound or computed tomography (CT) in thyroid cancer patients.

Efficacy of Low-Dose Radioiodine Ablation in Low- and Intermediate-Risk Differentiated Thyroid Cancer: A Retrospective Comparative Analysis

(1) Background-low-dose radioiodine ablation is an accepted strategy for the treatment of low- and intermediate-risk thyroid carcinomas, although there is no international consensus. The aim of this study is to describe the clinical experience with low-dose radioiodine ablation in patients with low- and intermediate-risk thyroid cancer compared to high-dose ablation. (2) Methods-174 patients with low- and intermediate-risk thyroid cancer, 90 treated with low-dose ablation and 84 treated with high-dose ablation, were included. The primary endpoint was response to treatment one year after ablation, defined by stimulated thyroglobulin, whole body scan and ultrasound imaging. (3) Results-an excellent response rate of 79.8% in the low-dose group and 85.7% in the high-dose group was observed (p = 0.049). Stimulated thyroglobulin at the moment of ablation (p = 0.032) and positive antithyroglobulin antibodies (p < 0.001) were independent predictive factors for nonexcellent response. Young age (p = 0.023), intermediate initial recurrence risk (p < 0.001) and low-dose ablation (p = 0.004) were independent predictive factors for recurrence. (4) Conclusion-low-dose ablation seemed to be less effective than high-dose ablation, especially in those patients with positive antithyroglobulin antibodies or higher stimulated thyroglobulin levels at the moment of ablation. Low dose was associated with higher recurrence rates, and lower age and intermediate initial recurrence risk were independent risk factors for recurrence in our sample.

Thermal Ablation for Small Papillary Thyroid Cancer: A Systematic Review

Background: Although clinical studies indicate that thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), the effectiveness of this treatment in patients with low-risk PTMC has not yet been systematically evaluated. Methods: Ovid-MEDLINE and EMBASE databases were searched for studies published through May 1, 2019, which report the efficacy of thermal ablation in patients with low-risk PTMCs. Data were extracted and methodological quality was assessed independently by two radiologists according to PRISMA guidelines. Results: This systematic review identified 503 low-risk PTMCs in 470 patients treated by thermal ablation from 9 studies. During follow-up, no patient experienced local tumor recurrence or distant metastasis, whereas two patients (0.4%) experienced lymph node (LN) metastasis. One patient (0.2%) developed a new PTMC, which was successfully treated by additional ablation. Five patients (1.1%) underwent delayed surgery after ablation, including the two patients with LN metastasis and three additional patients with unknown etiology. Conclusions: Thermal ablation is an excellent local tumor control method in patients with low-risk PTMCs. Strict inclusion criteria and technical expertise are required to obtain favorable results.

Active Surveillance of Papillary Thyroid Microcarcinoma: Where Do We Stand?

The recent sharp increase in thyroid cancer incidence is mainly due to increased detection of small papillary thyroid microcarcinoma (PTMC). Due to the indolent nature of the disease, active surveillance (AS) of low-risk PTMCs is suggested as an alternative to immediate surgery to reduce morbidity from surgery. For appropriately selected PTMC patients, AS can be a good management option and surgical intervention can be safely delayed until progression occurs. Many considerations must be taken into account at the time of initiation of AS, including radiological tumor characteristics and clinical characteristics of the patient. A specialized medical team should be assembled to monitor patients during AS with an appropriate follow-up protocol. The fact that some patients require surgery for disease progression after long-term follow-up is a major drawback of the current AS protocol. Evaluation of tumor kinetics by three-dimensional tumor volume measurement during the initial 2-3 years of AS may be helpful for discrimination of PTMCs that need early surgical intervention. In this review, we will discuss the clinical outcomes of surgical intervention and AS, considerations during AS, and unresolved questions about AS.

Active Surveillance for Small Papillary Thyroid Cancer: A Systematic Review and Meta-Analysis

Background: The rapid increase in the incidence of small papillary thyroid carcinoma (PTC) appears to be caused by the detection of small thyroid cancers. Active surveillance (AS) was therefore suggested to overcome this problem. As the results were favorable with low rates of size enlargement and lymph metastasis, the 2015 American Thyroid Association Management Guidelines endorsed AS as an alternative to immediate surgery. As the clinical value of AS is a subject of ongoing active discussions and surveys, we considered a systematic review and meta-analysis to be timely and necessary. Methods: Ovid-MEDLINE and EMBASE databases were searched up to January 5, 2019, for studies reporting patients who were followed up with AS for PTC. Data extraction and methodological quality assessment were performed independently by two radiologists. The primary outcomes were to identify the annual pooled proportions of size enlargement of 3 mm or more and the detection of lymph node metastases at a 5-year follow-up period. These were calculated using an inverse-variance weighting model. An additional outcome was evaluation of the reasons for surgery during AS. Results: The pooled proportion of size enlargement occurring at 5 years was 5.3% [95% confidence interval (CI), 4.4-6.4%], and the pooled proportion of 5-year lymph node metastasis was 1.6% [CI, 1.1-2.4%]. In many subjects undergoing delayed operations, the reasons for operation were often other than those of size enlargement or lymph node metastasis. Conclusions: AS is effective for the management of small PTC, with a low proportion of size enlargement or lymph node metastasis occurring at 5 years. However, a substantial proportion of the causes of delayed surgery were other than size enlargement or lymph node metastasis, and these situations need to be optimally managed.

Time-Varying Pattern of Mortality and Recurrence from Papillary Thyroid Cancer: Lessons from a Long-Term Follow-Up

Background: Little is known about annual hazard rates of cancer mortality and recurrence for papillary thyroid cancer (PTC). This study investigated the time-varying pattern of cancer death and recurrence from PTC and independent prognostic factors for cause-specific mortality (CSM) and recurrence of PTC. Methods: This retrospective chart review enrolled 466 patients diagnosed with PTC who underwent curative initial surgery between April 1981 and December 1991 with a median follow-up of 18.4 years. Clinical characteristics, cancer mortality (primary endpoint), and recurrence (secondary endpoint) were ascertained. The failure rates of either death or recurrence were estimated using the Kaplan-Meier methods, and annual death/recurrence hazard was depicted using hazard function. Results: In this Japanese cohort where only 1.5% of patients received radioactive iodine therapy, the 10-, 20-, and 30-year CSM rates were 2.7%, 6.2%, and 8.6%, respectively. Eleven (44.0%) cases of death occurred within the first 10 years, whereas 10 (40.0%) and 4 (16.0%) cases occurred within 10-20 and 20-30 years after surgery, respectively. The 10-, 20-, and 30-year recurrence rates were 11.3%, 21.8%, and 29.4%, respectively. Forty-six (54.8%) cases of recurrence occurred within the first 10 years, predominantly within the first five years (31 cases; 36.9%), whereas 29 (34.5%), 7 (8.3%), and 2 (2.4%) cases occurred within 10-20, 20-30, and ≥30 years after surgery, respectively. Age ≥55 years was the only independent prognostic factor for CSM. Age ≥55 years, male, tumor size > 4 cm, extranodal extension, and positive pathological lymph node metastasis were independent prognostic factors for recurrence. The annual hazard curve of cancer mortality presented a double-peaked distribution, with a first peak at the 10th year, and the second peak reaching the maximum at the 20th year after surgery for the entire population. The annual hazard curve of recurrence showed a triple-peaked pattern, with surges at about 12, 22, and 29 years after surgery. Conclusions: Patients with PTC harboring at least one of the prognostic characteristics may be at persistent risk of cancer mortality and recurrence even 10 or more years after initial treatment. Understanding the hazard rate of PTC is key to creating more tailored treatment and surveillance.

Radioguided occult lesion localization in patients with recurrent thyroid cancer

PURPOSE

Well planned re-surgery is critical for recurrent/persistent thyroid cancer (TC). We aimed to investigate the clinical outcome of radioguided-occult lesion localization (ROLL) guided surgery in patients with recurrent/persistent TC.

METHODS

This study includes 29 patients [F/M: 22/7, median age 43 ± 12 years (18-58)] with a diagnosis of TC (22 papillary, 2 follicular and 5 medullary). Before surgery, all patients underwent ultrasonography (USG) guided mapping and intra-lesional radioactivity injection. Surgery was performed based on the excision of radioactivity injected lesions by a gamma probe and non-injected tumor foci via USG-neck map. Researchers determined surgical success by post-operative tumor markers and neck-USG.

RESULTS

Among 29 patients, 60 metastatic lesions were identified by USG [median size 10 ± 6.3 mm (range 5-30)]. Neck-USG performed after surgery provided no evidence of disease (NED) in %97 (28/29) of TC patients. In the follow-up, stimulated thyroglobulin (Tg) levels were less than 1 ng/ml in 79%(19/24) of DTC patients and suppressed Tg < 0.2 ng/ml was noted in 92% (22/24).In patients with DTC with an incomplete structural response, we dramatically changed the American Thyroid Association (ATA) response category and achieved an excellent response in 92% (22/24) of patients. Among patients with MTC, 5/5 patients had normal USG and calcitonin levels were reduced by 60-80% in 4/5 and > 80% in1/5 patients.

CONCLUSIONS

In this study we have shown that, ROLL-guided surgery yielded NED rate of %97 (28/29) and increased excellent response rates according to ATA guidelines. Further studies with larger patient groups and longer follow-up should be performed to confirm the efficacy of this surgery.

Application of deep learning to the diagnosis of cervical lymph node metastasis from thyroid cancer with CT

PURPOSE

To develop a deep learning-based computer-aided diagnosis (CAD) system for use in the CT diagnosis of cervical lymph node metastasis (LNM) in patients with thyroid cancer.

METHODS

A total of 995 axial CT images that included benign (n = 647) and malignant (n = 348) lymph nodes were collected from 202 patients with thyroid cancer who underwent CT for surgical planning between July 2017 and January 2018. The datasets were randomly split into training (79.0%), validation (10.5%), and test (10.5%) datasets. Eight deep convolutional neural network (CNN) models were used to classify the images into metastatic or benign lymph nodes. Pretrained networks were used on the ImageNet and the best-performing algorithm was selected. Class-specific discriminative regions were visualized with attention heatmap using a global average pooling method.

RESULTS

The area under the ROC curve (AUROC) for the tested algorithms ranged from 0.909 to 0.953. The sensitivity, specificity, and accuracy of the best-performing algorithm were all 90.4%, respectively. Attention heatmap highlighted important subregions for further clinical review.

CONCLUSION

A deep learning-based CAD system could accurately classify cervical LNM in patients with thyroid cancer on preoperative CT with an AUROC of 0.953. Whether this approach has clinical utility will require evaluation in a clinical setting.

KEY POINTS

• A deep learning-based CAD system could accurately classify cervical lymph node metastasis. The AUROC for the eight tested algorithms ranged from 0.909 to 0.953. • Of the eight models, the ResNet50 algorithm was the best-performing model for the validation dataset with 0.953 AUROC. The sensitivity, specificity, and accuracy of the ResNet50 model were all 90.4%, respectively, in the test dataset. • Based on its high accuracy of 90.4%, we consider that this model may be useful in a clinical setting to detect LNM on preoperative CT in patients with thyroid cancer.

Long-Term Efficacy of Lymph Node Reoperation for Persistent Papillary Thyroid Cancer: 13-Year Follow-Up

BACKGROUND

Current recommendations for persistent or recurrent locoregional papillary thyroid cancer (PTC) include consideration of surgical resection versus active surveillance. The purpose of this study is to determine long-term outcomes after surgical resection of recurrent or persistent metastatic PTC in cervical lymph nodes after failure of initial surgery and radioactive iodine therapy using newer validated clinical outcomes measures.

METHODS

Outcomes of 70 patients who underwent cervical lymphadenectomy (n = 110) from 1999 to 2013 for recurrent or persistent locoregional PTC metastases were reviewed. Measures included biochemical remission (BCR) based on Tg levels, American Thyroid Association classifications for response to treatment [biochemical incomplete response (BIR), structural incomplete response (SIR), indeterminate response (IR), and excellent response (ER)], need for reoperation, surgical complications, disease progression, and death.

RESULTS

The median follow-up was 13.1 years, with only two additional reoperations since 2010, one of which had no metastasis on pathology with the other developing anaplastic thyroid cancer in background PTC. ER was achieved in 31 (44%) patients, all of whom remained in ER at time of last follow-up (median 14.1 years). There were no structural recurrences in patients with persistent BIR or IR after reoperation. Patients with SIR had stable disease, except for one who died due to anaplastic thyroid cancer.

CONCLUSIONS

Patients who achieved ER after reoperation had no need for further treatment. Patients with persistent detectable Tg levels after reoperation rarely developed structural recurrence. ATA outcomes can be safely used to guide treatment decisions over a decade after reoperation for PTC.