Management of patients with low-risk papillary thyroid carcinoma

Follow-up and Outcomes of 186 Patients With Follicular Cell-Derived Thyroid Cancer Seen at a Referral Center by One Thyroidologist in 2015

OBJECTIVE

To study the profile, management, and outcomes of follicular cell-derived thyroid cancer (FCDTC) before publication of the 2016 American Thyroid Association guidelines recommending less-aggressive thyroid cancer procedures.

METHODS

Patients with FCDTC were seen by one thyroidologist at Mayo Clinic during the 2015 calendar year. Patients underwent surgical procedures for FCDTC in 2015 or earlier at Mayo Clinic or another institution. Follow-up data were collected from January 1, 2016, through July 20, 2022. Outcomes measured included tumor characteristics, treatment methods, adverse effects, diagnostic imaging methods, and primary tumor/metastasis status at the last follow-up.

RESULTS

Of 186 included patients, 85 had total or near-total thyroidectomy. Bilateral disease was present in 35.5% of these patients, and contralateral involvement would have been missed by lobectomy for 9 (10%) patients with low-risk thyroid cancer. Additionally, 57% had positive neck lymph nodes identified during their surgical procedure, 25% (21% in central compartment) of which were undetected by preoperative ultrasonography. At the last follow-up, 65.6% of patients had no evidence of disease and 10.7% had distant metastases.

CONCLUSION

This report outlines the profile and outcomes of patients with FCDTC who were treated at a referral center before the revised 2016 American Thyroid Association guidelines. Lobectomy for low-risk FCDTC may miss some cancer in the contralateral lobe. However, the clinical importance of these missed microcarcinomas is unclear. Preoperative ultrasonography effectively predicts lateral, but not central compartment, nodal metastases.

Clinical and molecular features of progressive papillary thyroid microcarcinoma

In recent decades, the prevalence of thyroid cancer has risen substantially, with papillary thyroid microcarcinoma (PTMC) constituting over 50% of cases. Although most PTMCs exhibit indolent growth and a favorable prognosis, some present an increased risk of recurrence and an unfavorable prognosis due to high-risk characteristics such as lymph node metastasis, extrathyroidal extension, and distant metastasis. The early identification of clinically progressing PTMC remains elusive. In this review, the authors summarize findings from PTMC progression-related literature, highlighting that factors such as larger tumor size, cervical lymph node metastasis, extrathyroidal extension, younger age, higher preoperative serum thyroid-stimulating hormone levels, family history, and obesity positively correlate with PTMC progression. The role of multifocality in promoting PTMC progression; however, remains contentious. Furthermore, recent studies have shed light on the impact of mutations, such as BRAF and TERT mutations, on PTMC progression. Researchers have identified several mRNAs, noncoding RNAs, and proteins associated with various features of PTMC progression. Some studies propose that peripheral and tumor tissue-infiltrating immune cells could serve as biomarkers for the clinical progression of PTMC. Collectively, these clinical and molecular features offer a rationale for the early detection and the development of precision theranostic strategies of clinically progressive PTMC.

The frequency of risk pathological characteristics in clinically low-risk papillary thyroid microcarcinoma suitable for active surveillance

PURPOSE

Active surveillance has emerged as an initial management strategy for patients with low-risk papillary thyroid microcarcinoma (PTMC). The main objective of this research was to investigate the frequency of risk pathological characteristics among patients with clinically low-risk PTMC who are suitable for Active Surveillance.

METHODS

A retrospective review was conducted on patients who underwent lobectomy for PTMC between January 2013 and December 2018. Patients with bilateral tumors, macroscopic multifocal tumors, macroscopic extrathyroidal extension (ETE), clinical lymph node metastases, macroscopic extranodal extension (ENE), distant metastases, a history of neck radiation or familial thyroid cancer were excluded. Pathological characteristics were collected from the postoperative pathological results. Aggressive variants, multifocality, ETE, lymphovascular invasion (LVI), perineural invasion (PNI), metastatic lymph nodes (LNs) ≥ 5, and ENE were defined as risk characteristics.

RESULTS

The study included 4923 patients, of whom 1229 (25.0%) were male. The mean age was 43 years. A total of 2250 patients (45.7%) exhibited risk characteristics. Among them, 15 patients presented with aggressive variants, and 1813 patients (36.8%) had ETE. Multifocality, LVI, and PNI were observed in 551 (11.2%), 21 (0.4%), and 40 (0.8%) patients, respectively. A total of 139 patients (2.8%) had five or more metastatic LNs, and ENE was identified in 140 patients. Notably, 172 patients (3.5%) fulfilled the criteria for completion thyroidectomy, as they had aggressive variants, LVI, or five or more metastatic LNs.

CONCLUSIONS

Nearly half of the patients diagnosed with clinically low-risk PTMC exhibited risk pathological characteristics, and a small proportion of patients met the criteria for completion thyroidectomy.

Efficacy and safety of thermal ablation modalities for the treatment of papillary thyroid microcarcinoma: Systematic Review and network meta-analysis

Background

Thermal ablation (TA) modalities such as radiofrequency ablation (RFA), microwave ablation (MWA), and laser ablation (LA) have been widely used in the treatment of papillary thyroid microcarcinoma (PTMC) patients. Based on previous small-sample meta-analyses, this network meta was designed to further compare the efficacy and safety of these thermal ablation methods in PTMC patients.

Methods

China National Knowledge Infrastructure (CNKI), Wanfang, PubMed, Embase, and the Cochrane Library databases were searched to retrieve relevant studies published before May 2022. The efficacy outcomes was recurrence and lymph node metastasis (LNM), the safety outcome included operation time, intra-operative blood loss, hospital stays and complications. The Newcastle-Ottawa Scale (NOS) was selected for the risk of bias assessment. Stata 14.0 was used for statistical analysis.

Results

Twenty-nine articles were included. Based on as least 6 months follow up, our analysis discovered no significant statistical differences in all efficacy and safety outcomes between MWA, RFA, and LA groups. Moreover, three TA treatments all produced significant least operation time, hospital stays, and complications than surgery group. Additionally, our study found that RFA showed relatively less complications, LNM, operation time and intra-operative blood loss, compared with other TA treatments. MWA indicated the lowest probability of recurrence, LA showed the longest hospital stays.

Conclusions

MWA, RFA, and LA are all effective treatment strategies for patients with PTMC, but could not completely replace conventional surgical treatment.

Active Surveillance for Low-Risk Thyroid Cancers: A Review of Current Practice Guidelines

The indolent nature and favorable outcomes associated with papillary thyroid microcarcinoma have prompted numerous prospective studies on active surveillance (AS) and its adoption as an alternative to immediate surgery in managing low-risk thyroid cancer. This article reviews the current status of AS, as outlined in various international practice guidelines. AS is typically recommended for tumors that measure 1 cm or less in diameter and do not exhibit aggressive subtypes on cytology, extrathyroidal extension, lymph node metastasis, or distant metastasis. To determine the most appropriate candidates for AS, factors such as tumor size, location, multiplicity, and ultrasound findings are considered, along with patient characteristics like medical condition, age, and family history. Moreover, shared decision-making, which includes patient-reported outcomes such as quality of life and cost-effectiveness, is essential. During AS, patients undergo regular ultrasound examinations to monitor for signs of disease progression, including tumor growth, extrathyroidal extension, or lymph node metastasis. In conclusion, while AS is a feasible and reliable approach for managing lowrisk thyroid cancer, it requires careful patient selection, effective communication for shared decision-making, standardized follow-up protocols, and a clear definition of disease progression.

Long-term efficacy of microwave ablation for multifocal papillary thyroid microcarcinoma: a 5-year follow-up study

OBJECTIVES

Microwave ablation (MWA) has achieved excellent long-term efficacy in treating unifocal papillary thyroid microcarcinoma (UPTMC). The therapeutic effect of this treatment on multifocal papillary thyroid microcarcinoma (MPTMC) is unknown. Therefore, we evaluated the long-term efficacy of MWA for low-risk MPTMC and to provide evidence-based medicine for the revision of clinical guidelines.

METHODS

This study included 66 MPTMC patients with a total of 158 lesions, all of whom received MWA. We collected and retrospectively analyzed the patients' follow-up data before MWA, at 1, 3, 6, and 12 months posttreatment and every 6 months thereafter until 5 years posttreatment. We evaluated the MWA complication rate, technical success rate (TSR), lesion volume reduction rate (VRR), and complete disappearance rate (CDR) during follow-up and in those patients with tumor progression and delayed surgery.

RESULTS

After 60 months of follow-up, all 158 lesions disappeared in 66 patients, and the volume was reduced from 43.82 mm3 to 0.00 mm3. The TSR and VRR were both 100%. The CDRs at 1 year, 2 years, and 3 years were 57.59%, 93.67%, and 100%, respectively. The complication rate was 3.03% (2/66), and the incidence of tumor progression was 3.03% (2/66), including one new intrathyroidal lesion and one cervical lymph node metastasis (LNM). These lesions were retreated with MWA, and the lesions disappeared during the follow-up period.

CONCLUSIONS

Ultrasound-guided MWA for low-risk MPTMC is safe and effective and may serve as an alternative option for patients who refuse surgery or active surveillance (AS).

CLINICAL RELEVANCE STATEMENT

This study concludes that ultrasound-guided microwave ablation for low-risk multifocal papillary thyroid microcarcinoma is safe and effective and may serve as an alternative option for patients who refuse surgery or active surveillance.

KEY POINTS

• Ultrasound-guided microwave ablation for low-risk multifocal papillary thyroid microcarcinoma is safe and effective. • During 5 years of follow-up, multifocal papillary thyroid microcarcinoma patients treated with microwave ablation had a favorable prognosis. • To provide evidence-based medicine for the revision of clinical guidelines.

A prediction model for identifying high-risk lymph node metastasis in clinical low-risk papillary thyroid microcarcinoma

BACKGROUND

The presence of high-volume lymph node metastasis (LNM) and extranodal extension (ENE) greatly increases the risk of recurrence in patients with low-risk papillary thyroid microcarcinoma (PTMC). The goal of this research was to analyze the factors that contribute to high-risk lymph node metastasis in patients with low-risk PTMC.

METHODS

We analyzed the records of 7344 patients who were diagnosed with low-risk PTMC and treated at our center from January 2013 to June 2018.LNM with a high volume or ENE was classified as high-risk lymph node metastasis (hr-LNM). A logistic regression analysis was conducted to identify the risk factors associated with hr-LNM. A nomogram was created and verified using risk factors obtained from LASSO regression analysis, to predict the likelihood of hr-LNM.

RESULTS

The rate of hr-LNM was 6.5%. LASSO regression revealed six variables that independently contribute to hr-LNM: sex, age, tumor size, tumor location, Hashimoto's thyroiditis (HT), and microscopic capsular invasion. A predictive nomogram was developed by integrating these risk factors, demonstrating its excellent performance. Upon analyzing the receiver operating characteristic (ROC) curve for predicting hr-LNM, it was observed that the area under the curve (AUC) had a value of 0.745 and 0.730 in the training and testing groups showed strong agreement, affirming great reliability.

CONCLUSION

Sex, age, tumor size, tumor location, HT, and microscopic capsular invasion were determined to be key factors associated with hr-LNM in low-risk PTMC. Utilizing these factors, a nomogram was developed to evaluate the risk of hr-LNM in patients with low-risk PTMC.

Dynamic Risk Stratification Integrated with ATA Risk System for Predicting Long-Term Outcome in Papillary Thyroid Cancer

BACKGROUND

In recent years, there has been a renewed interest in thyroid cancer management paradigms that use individualized risk assessments as the basis for treatment and follow-up recommendations. In this study, we assumed that the long-term follow-up of differentiated thyroid cancer patients might be better tailored by integrating the response to initial therapy with the America Thyroid Association (ATA) risk classes.

METHODS

This retrospective study included low- and intermediate-risk papillary thyroid cancer (PTC) patients followed up for a median time of 8 years and classified according to the response to initial therapy assessed 6-12 months after initial treatment.

RESULTS

After a median follow-up of 8 years, in the initial excellent response subgroup of PTC patients (n = 522), the rate of recurrent disease was significantly higher in intermediate-risk patients than in low-risk PTC patients (6.9% versus 1.2%, p = 0.0005). Similarly, in the initial biochemical incomplete response subgroup (n = 82), the rate of excellent response was significantly higher in low-risk PTC patients (58.0%) than in intermediate-risk PTC patients (33.3%) (p = 0.007). Finally, in the initial structural incomplete response subgroup (n = 66), the rate of excellent response was higher in low-risk patients (80.0%) than in intermediate-risk patients (46.4%) (p = 0.08). Moreover, all patients with initial indeterminate response had an excellent response at the last follow-up visit. ATA risk classes were independently associated with long-term outcome in each subgroup of patients classified dynamically after initial therapy and the overall prognostic performance, defined via ROC curve analysis, of response to initial therapy integrated with the ATA risk system (AUC: 0.89; 95% CI: 0.86-0.92) was significantly higher compared to the ATA risk stratification (AUC 0.69; 95% CI: 0.65-0.74, p < 0.001) or the dynamic risk stratification (DRS) systems alone (AUC: 0.86 95% CI: 0.82-0.90, p = 0.007).

CONCLUSIONS

This study of a large cohort of PTC patients showed that the initial ATA risk criteria may be useful for improving the risk-adapted management of PTC patients based on the response to initial therapy.

Clinical and ultrasonic risk factors for high-volume central lymph node metastasis in cN0 papillary thyroid microcarcinoma: A retrospective study and meta-analysis

OBJECTIVE

Papillary thyroid microcarcinoma (PTMC) comprises more than 50% of all newly detected cases of papillary thyroid carcinoma (PTC). High-volume lymph node metastasis (involving >5 lymph nodes) (hv-LNM) is associated with PTMC recurrence. In half of the clinically node-negative (cN0) PTMC patients, central lymph node metastasis (CLNM) is pathologically present. However, clinical risk factors for high-volume CLNM (hv-CLNM) in cN0 PTMC have not been defined well. Therefore, we aimed to obtain evidence for hv-CLNM risk factors in cN0 PTMC.

DESIGN

Data on patients who visited our hospital between January 2020 and December 2021 were collected; a preoperative diagnosis of cN0 and a postoperative pathological confirmation of PTMC were obtained. After filtering by inclusion versus exclusion criteria, the obtained data (N = 2268) were included in the meta-analysis. Relevant studies published as of 10 April 2022, were identified from the Web of Science, PubMed, WANFANG, and CNKI databases. These eligible studies were included in the meta-analysis and the association between clinicopathological factors and hv-CLNM in cN0 PTMC was assessed. SPSS and MetaXL were used for statistical analyses.

RESULTS

The meta-analysis included 10 previous studies (11,734 patients) and 2268 patients enroled in our hospital for a total of 14,002 subjects. The results of which suggested that younger age (<40, odds ratio [OR] = 3.28, 95% confidence interval [CI] = 2.75-3.92, p < .001 or <45 odds ratio [OR] = 2.93, 95% CI = 2.31-3.72, p < .001), male sex (OR = 2.81, 95% CI = 2.25-3.52, p < .001), tumour size >5 mm (OR = 1.85, 95% CI = 1.39-2.47, p < .001), multifocality (OR = 1.88, 95% CI = 1.56-2.26, p < .001), extrathyroidal extension (OR = 2.58, 95% CI = 2.02-3.30, p < .001), capsule invasion (OR = 2.02, 95% CI = 1.46-2.78, p < .001), microcalcification (OR = 3.25, 95% CI = 2.42-4.36, p < .001) and rich blood flow (OR = 1.65, 95% CI = 1.21-2.25, p = .002) were the significant factors related to an elevated hv-CLNM risk in cN0 PTMC patients. Hashimoto thyroiditis (OR = 0.76, 95% CI = 0.55-1.07, p = .114), irregular margin (versus regular margin, OR = 0.96, 95% CI = 0.68-1.33, p = .787) and hypoechoic (versus nonhypoechoic, OR = 1.27, 95% CI = 0.84-1.92, p = .261) showed no significant association with hv-CLNM.

CONCLUSIONS

Younger age, tumour size >5 mm, males, extrathyroidal extension, multifocality, microcalcification, capsular invasion, and rich blood flow were the significant clinicopathological risk factors for hv-CLNM risk in cN0 PTMC patients. These predictors may compensate for the sensitivity of imaging diagnosis in the preoperative period, thus helping in the effective identification of PTMCs with an invasive phenotype.

Ultrasound-guided thermal ablation for papillary thyroid microcarcinoma: A systematic review

OBJECTIVE

Thyroidectomy is the first-line treatment for papillary thyroid microcarcinoma (PTMC), but often involves aggressive overtreatment. Thermal ablation (TA) has been gradually used for the treatment of recurrent PTMC. However, it is not recommended for the treatment of primary PTMC according to the Korean and Italian guidelines. Therefore, this systematic review aimed to analyse the indications, efficacy, and safety of TA in the treatment of PTMC.

DESIGN

Systematic review.

PATIENTS AND MEASUREMENTS

A search strategy was developed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. A total of 27 articles were included in this study until January 2022.

RESULTS

According to current guidelines and studies, we divided the indications of TA for PTMC into six primary and three secondary indications. Laser ablation (LA) has the advantages of a small needle, accurate output energy and precision ablation, and it is safe to important organs around the lesion. The patients recover quickly after radiofrequency ablation (RFA), with no major complications, recurrence, or lymph node metastasis. The volume reduction rate after RFA was the highest, followed by microwave ablation and LA, and the improvement in patient quality of life after TA was significantly better than after thyroidectomy.

CONCLUSIONS

TA is an effective alternative method for surgery in the treatment of low-risk PTMC and has the advantages of being minimally invasive, economical, having less bleeding and having a high postoperative quality of life.

Histogram-based analysis of diffusion-weighted imaging for predicting aggressiveness in papillary thyroid carcinoma

BACKGROUND

To assess the potential of apparent diffusion coefficient (ADC) map in predicting aggressiveness of papillary thyroid carcinoma (PTC) based on whole-tumor histogram-based analysis.

METHODS

A total of 88 patients with PTC confirmed by pathology, who underwent neck magnetic resonance imaging, were enrolled in this retrospective study. Whole-lesion histogram features were extracted from ADC maps and compared between the aggressive and non-aggressive groups. Multivariable logistic regression analysis was performed for identifying independent predictive factors. Receiver operating characteristic curve analysis was used to evaluate the performances of significant factors, and an optimal predictive model for aggressiveness of PTC was developed.

RESULTS

The aggressive and non-aggressive groups comprised 67 (mean age, 44.03 ± 13.99 years) and 21 (mean age, 43.86 ± 12.16 years) patients, respectively. Five histogram features were included into the final predictive model. ADC_firstorder_TotalEnergy had the best performance (area under the curve [AUC] = 0.77). The final combined model showed an optimal performance, with AUC and accuracy of 0.88 and 0.75, respectively.

CONCLUSIONS

Whole-lesion histogram analysis based on ADC maps could be utilized for evaluating aggressiveness in PTC.

Radioiodine remnant ablation in stage I adult papillary thyroid carcinoma: does it improve postoperative outcome?

Objective

To determine whether radioiodine remnant ablation (RRA) reduces cause-specific mortality (CSM) or tumor recurrence rates (TRR) after potentially curative bilateral thyroidectomy (BT) in low-risk adult papillary thyroid carcinoma (APTC) patients, we compared postoperative outcomes in 1836 pTNM stage I APTC patients having BT alone with 832 having BT+RRA during two consecutive 25-year periods.

Methods

The THEN cohort (consecutively managed during 1966-1990) comprised 809 patients (36% having BT+RRA) and the NOW cohort (1991-2015) comprised 1859 patients (29% BT+RRA). Analyses of differences in occurrence rates between BT alone and BT+RRA patients were performed with SAS software.

Results

During 1966-1990, when RRA rates rose ten-fold, 20-year CSM after BT alone was 0.6% and after BT+RRA was 1.2% (P = 0.66); during 1991-2015, when RRA rates progressively fell, no PTC deaths occurred in 1859 patients. In the THEN cohort, RRA did not significantly improve TRR at local, regional, or distant sites (P > 0.1), when compared to BT alone. RRA in NOW cohort was administered to 49% of node-positive (pN1) patients and 17% of node-negative (pN0/NX) patients (P < 0.0001); TRR therefore, were examined separately for pN0/NX and pN1 patients. In 1157 pN0/NX cases, 20-year locoregional TRR were 3.1% after BT and were higher (P = 0.049) at 8.6% after BT+RRA. In four pN1 groups, stratified by metastatic nodal burden, RRA did not significantly reduce the locoregional TRR observed after BT with curative intent (P > 0.5).

Conclusions

In a 5-decade experience, RRA administered postoperatively to stage I APTC patients did not reduce either CSM or TRR and should probably not be indicated when such patients undergo potentially curative BT.

The 2015 American Thyroid Association guidelines and trends in hemithyroidectomy utilization for pediatric thyroid cancer

BACKGROUND

In 2015, the American Thyroid Association (ATA) released its inaugural recommendations for the management of thyroid cancer in children. We aim to evaluate whether there has been a change in hemithyroidectomy utilization for pediatric differentiated thyroid cancer, and the association between those changes and the release of the ATA guidelines.

METHODS

The National Cancer Database was queried and identified 4776 patients ≤18 years old with differentiated thyroid cancer. Causal impact time-series analysis and logistic analysis were utilized to assess factors associated with use of hemithyroidectomy.

RESULTS

Post-2015 hemithyroidectomy rate was greater than predicted based on preguideline trends (predicted: 8.4%, actual: 12.6%, p = 0.001). In logistic analysis of factors associated with hemithyroidectomy use, we find that Papillary histology, tumor size >1 cm, nodal examination, and positive nodes were associated with lower rate of hemithyroidectomy (OR: 0.23, 0.51, 0.62, and 0.18, respectively).

CONCLUSION

There has been a significant increase in hemithyroidectomy utilization for pediatric differentiated thyroid cancer.

A cohort study of microwave ablation and surgery for low-risk papillary thyroid microcarcinoma

BACKGROUND

The optimal treatment method for papillary thyroid microcarcinoma (PTMC) is lacking consensus. Here we aimed to compare the efficacy and safety of surgery and microwave ablation (MWA) for PTMC.

METHODS

The clinical data of 644 patients with PTMC treated between July 2013 and June 2020 were retrospectively analyzed. A total of 320 and 324 patients underwent MWA and surgery, respectively. We observed lesion changes in the MWA group and compared the recurrence, metastasis, complications, and other health economic indicators between the 2 groups.

RESULTS

The mean follow-up time was 890.7 ± 532.9 (187.9-2679.0) days in the MWA group and 910.9 ± 568.4 (193.8-2821.5) days in the surgery group. In the MWA group, lesion volume increased significantly after ablation and then gradually decreased. The final lesion volume reduction rate was 90.73% ± 7.94%, and 193 lesions (60.3%) disappeared completely. There were no significant intergroup differences in recurrence or metastasis. The incidence of main complications (temporary hypothyroidism, hypoparathyroidism, and temporary hoarseness) was significantly lower in the MWA group than in the surgery group (p < 0.001). The treatment time, intraoperative blood loss, and hospital stay were significantly lower in the MWA group than in the surgery group (p < 0.001).

CONCLUSIONS

MWA is effective for treating PTMC, with a low incidence of complications and less trauma. The rates of post-treatment recurrence and metastasis are similar to those of surgery, indicating that MWA is a suitable alternative to surgery.

Comparison of Thermal Ablation and Surgery for Low-Risk Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Objective

Although thermal ablation is effective in treating low-risk papillary thyroid microcarcinomas (PTMCs), comparison of treatment outcomes between thermal ablation and surgery has not yet been systematically evaluated. This study aimed to compare the efficacy and safety of thermal ablation and surgery for the treatment of low-risk PTMCs.

Materials and Methods

Ovid-MEDLINE and EMBASE databases were searched for studies reporting comparisons of treatment results between thermal ablation and surgery for patients with low-risk PTMC published up to April 6, 2020. The analysis evaluated the efficacy (local tumor recurrence, occurrence of new tumor, metastasis, and rescue surgery) and safety (complication rate) of thermal ablation and surgery.

Results

This systematic review included four studies with a total of 339 PTMCs in 339 patients who underwent thermal ablation and 320 PTMCs in 314 patients who underwent surgery. There was no local tumor recurrence or distant metastasis in either group. There was no significant difference in the pooled proportion of lymph node metastasis (2.6% with thermal ablation vs. 3.3% with surgery, p = 0.65), occurrence of new tumors (1.4% with thermal ablation vs. 1.3% with surgery, p = 0.85), or rescue surgery (2.6% with thermal ablation vs. 1.6% with surgery, p = 0.62). However, the pooled complication rate was significantly higher in the surgery group than in the ablation group (3.3% with thermal ablation vs. 7.8% with surgery, p = 0.03).

Conclusion

Both thermal ablation and surgery are effective and safe options for the management of low-risk PTMCs, with thermal ablation achieving a lower complication rate. Therefore, thermal ablation may be considered as an alternative treatment option for low-risk PTMC in patients who refuse surgery and active surveillance or are ineligible for surgery.

Inability of Radioiodine Remnant Ablation to Improve Postoperative Outcome in Adult Patients with Low-Risk Papillary Thyroid Carcinoma

OBJECTIVE

To determine whether radioiodine remnant ablation (RRA) reduces cause-specific mortality (CSM) or tumor recurrence (TR) rate after bilateral lobar resection (BLR).

PATIENTS AND METHODS

There were 2952 low-risk adult papillary thyroid cancer (LRAPTC) patients (with MACIS scores <6) who underwent potentially curative BLR during 1955-2014. During 1955-1974, 1975-1994, and 1995-2014, RRA was administered in 3%, 49%, and 28%. Statistical analyses were performed using SAS software.

RESULTS

During 1955-1974, the 20-year CSM and TR rates after BLR alone were 1.0% and 6.8%; rates after BLR+RRA were 0% (P=.63) and 5.9% (P=.82). During 1975-1994, post-BLR 20-year rates for CSM and TR were 0.3% and 7.5%; after BLR+RRA, rates were higher at 0.9% (P=.31) and 12.8% (P=.01). When TR rates were examined separately for 448 node-negative and 317 node-positive patients, differences were nonsignificant. In 1995-2014, post-BLR 20-year CSM and TR rates were 0% and 9.2%; rates after BLR+RRA were higher at 1.4% (P=.19) and 21.0% (P<.001). In 890 pN0 cases, 15-year locoregional recurrence rates were 3.4% after BLR and 3.7% after BLR+RRA (P=.99). In 740 pN1 patients, 15-year locoregional recurrence rates were 10% higher after BLR+RRA compared with BLR alone (P=.01). However, this difference became nonsignificant when stratified by numbers of metastatic nodes.

CONCLUSION

RRA administered to LRAPTC patients during 1955-2014 did not reduce either the CSM or TR rate. We would therefore not recommend RRA in LRAPTC patients undergoing BLR with curative intent.

Predictive Value of a Prognostic Model Based on Lymphocyte-to-Monocyte Ratio Before Radioiodine Therapy for Recurrence of Papillary Thyroid Carcinoma

BACKGROUND

The aim of this study was to investigate the predictive value of a prognostic model based on the lymphocyte-to-monocyte ratio (LMR) before radioiodine treatment for the recurrence of papillary thyroid carcinoma (PTC).

METHODS

Clinicopathological data of 441 patients with papillary thyroid cancer were collected retrospectively. The Receiver operating characteristic (ROC) was used to determine the optimal cut-off value for predicting PTC recurrence by LMR before radioiodine treatment. Recurrence was the endpoint of the study, and survival was estimated by the Kaplan-Meier method, and any differences in survival were evaluated with a stratified log-rank test. Univariate and multifactorial analyses were performed using Cox proportional-hazards models to identify risk factors associated with PTC recurrence.

RESULTS

The ROC curve showed that the best cut-off value of LMR before radioiodine treatment to predict recurrence in patients with PTC was 6.61, with a sensitivity of 54.1%, a specificity of 73%, and an area under the curve of 0.628. The recurrence rate was significantly higher in the low LMR group (16%) than in the high LMR group (5%) (P = 0.001, χ² = 12.005). Multifactorial analysis showed that LMR < 6.61 (P = 0.006; HR = 2.508) and risk stratification (high risk) (P = 0.000; HR = 5.076) before radioiodine treatment were independent risk factors predicting recurrence in patients with PTC. Patients with preoperative LMR < 6.61 and high risk stratification had the lowest recurrence-free survival rate and the shortest recurrence-free survival time.

CONCLUSIONS

The LMR-based prognostic model before radioactive iodine treatment is valuable for early prediction of PTC recurrence and it can be used in clinical practice as a supplement to risk stratification and applied in combination to help screen out patients with poorer prognosis early.

A Stepwise Approach Using Metastatic Lymph Node Ratio-Combined Thyroglobulin for Customization of [18F]FDG-PET/CT Indication to Detect Persistent Disease in Patients with Papillary Thyroid Cancer

We investigated whether an indication for [¹⁸F]FDG-PET/CT to detect FDG-avid persistent disease (PD) could be identified precisely using the extent of metastatic lymph nodes (MLNs) and serum thyroglobulin (Tg) in papillary thyroid cancer (PTC) patients. This retrospective study included 429 PTC patients who underwent surgery and radioactive iodine (RAI) therapy. [¹⁸F]FDG-PET/CT and serum Tg were evaluated just before RAI therapy. The MLN ratio (LNR) was defined as the ratio of the number of MLNs to the number of removed LNs. To derive the LNR-combined criteria, different Tg cut-off values for identifying the PET/CT-indicated group for PD detection were applied individually to subgroups initially classified based on LNR cut-off values. The cut-off values for serum Tg, the number of MLNs, and LNR for a PET/CT indication were 6.0 ng/mL, 5, and 0.51, respectively. Compared to a single parameter (serum Tg, total number of MLNs, and LNR), the LNR-combined criteria showed significantly superior diagnostic performance in detecting FDG-avid PD (p < 0.001). The diagnostic performance of PET/CT in detecting FDG-avid PD was significantly improved when the PET/CT-indicated group was identified through the LNR-combined criteria in a stepwise manner; this can contribute to a customized PET/CT indication in PTC patients.

Added Value of Postoperative Radioiodine Scan for Staging and Risk Stratification in Papillary Thyroid Microcarcinoma

Objective

The complete staging and risk stratification of Papillary thyroid microcarcinoma (PTMC) is usually not done due to its theoretically low recurrence rates. This study aimed to determine the value of postoperative radioiodine diagnostic scan and SPECT/CT for the accurate staging and risk stratification in PTMC patients.

Methodology

This study was a retrospective review of PTMC patients from January 2014 to May 2017 who underwent I-131 scans. All PTMC patients were initially staged by the 8^th edition AJCC/TNM staging system and risk-stratified, based on clinical information, histopathology and stimulated thyroglobulin (sTg). After I-131 scan, staging and risk stratification were re-assessed. The proportion of patients who ended up with a higher stage and risk stratification were reported.

Results and Conclusion

Fifty-two patients were included. The overall upgrading of cancer stage was 7.7 %. The overall higher risk stratification was 19.2% with radioiodine-avid lymph node, lung, and bone metastases. Neck and paratracheal node metastases were found in 37.3% of the initial low-risk patients with sTg less than 5 ng/mL. Lung metastasis was found in the initial intermediate-risk patient. The I-131 scan helps to localize metastatic lesions and results in a higher stage in 50% of the initial high-risk patients. This study provides some evidence showing the value of postoperative radioiodine WBS for accurate staging and risk stratification in PTMC patients. Larger studies with analytical design should be further performed to prove its significant utility.

Microcarcinoma papilar de tiroides: ¿es adecuada la selección para protocolo de vigilancia activa?

Introducción. Los microcarcinomas papilares de tiroides son tumores de hasta 10 mm en su diámetro mayor. Su tratamiento es sujeto de debate y se propone, desde seguimiento clínico, hasta intervención quirúrgica temprana. Este estudio buscó identificar factores de riesgo relacionados con compromiso ganglionar, que permitan una mejor selección de los pacientes en nuestro medio, en quienes se propone manejo quirúrgico inmediato o vigilancia activa, en consonancia con la clasificación del riesgo de progresión. Métodos. Estudio de cohorte analítica ambispectiva que incluyó pacientes con microcarcinoma papilar de tiroides llevados a tiroidectomía más vaciamiento central. Se caracterizó la población y se realizó un análisis de regresión logística multivariado para definir factores preoperatorios asociados al compromiso ganglionar. Adicionalmente, se evaluó de manera retrospectiva la eventual asignación a grupos de riesgo de progresión, según los criterios de Miyauchi, y su comportamiento respecto al estado nodal. Resultados. Se incluyeron 286 pacientes. El 48,9 % presentó compromiso ganglionar, y de estos, el 33,5 % presentó compromiso ganglionar significativo, que modificó su clasificación de riesgo de recaída. De estos últimos, el 59,5 % hubiesen sido manejados con vigilancia activa, según los criterios propuestos por Miyauchi. Se identificó que la edad menor de 55 años, los ganglios sospechosos en la ecografía y los nódulos mayores de 5 mm, se relacionan con compromiso ganglionar significativo. Discusión. El manejo quirúrgico inmediato parece ser una opción adecuada para pacientes con sospecha de compromiso ganglionar en ecografía preoperatoria, pacientes menores de 55 años y nódulos mayores de 5 mm. Es posible que los actuales criterios para definir vigilancia activa no seleccionen adecuadamente a los pacientes en nuestro medio.

Interobserver Reproducibility in Sonographic Measurement of Diameter and Volume of Papillary Thyroid Microcarcinoma

Background: Active surveillance is recommended as an alternative to immediate surgery for low-risk papillary thyroid microcarcinoma (PTMC), and determining meaningful changes in diameter and volume on ultrasonography (US) is critical. However, interobserver reproducibility of the sonographic measurement of maximum diameter and volume of PTMC has not been well established. We aimed to determine the reproducibility in the measurement of maximum diameter and volume of PTMC on US. Methods: Consecutive patients who underwent US for pathologically proven PTMC between December 2018 and December 2019 were retrospectively reviewed. Two observers independently performed sonographic measurement of each nodule using standardized measurement methods. Each observer measured maximum transverse, anteroposterior, and longitudinal nodule diameters, and using these, nodule volume was calculated using the ellipsoid formula. Interobserver reproducibility in the measurement of the maximum diameter and volume was assessed using percentage reproducibility coefficient (RC). Z-tests of the intraclass correlation coefficients (ICCs) were used to compare the interobserver reproducibility in subgroups defined according to sonographic characteristics, such as the presence of microcalcification, nodule size, and parenchymal heterogeneity. Results: A total of 197 thyroid nodules from 188 patients were included in the study series. The percentage RCs were 71.8% [95% confidence interval, CI 65.4-79.7%] and 23.7% [CI 21.6-26.3%] for volume and maximum diameter measurements, respectively. There were no significant differences noted in the ICC values according to nodule orientation, presence of calcifications, size, or parenchymal heterogeneity. Conclusion: For PTMC, a difference of up to 24% in the maximum diameter and 72% in the volume may be considered to be within measurement error on US. This value may be used to determine the cutoff for defining meaningful change in the maximum diameter and volume for PTMC during active surveillance.

Comparison of ultrasound guided percutaneous radiofrequency ablation and open thyroidectomy in the treatment of low-risk papillary thyroid microcarcinoma: A propensity score matching study

PURPOSE

The aim of this study was to evaluate the efficacy, safety and costs of ultrasound guided percutaneous radiofrequency ablation (RFA) versus open thyroidectomy for treating low-risk papillary thyroid microcarcinoma (PTMC) by using propensity score matching (PSM).

PATIENTS AND METHODS

157 patients who underwent RFA and 206 patients who underwent surgery for low-risk PTMC were included in the study. The patients were followed up at 1, 3, 6, 12 months after treatment, and every half year thereafter. A 1:1 PSM method was applied to balance the pretreatment data of the two groups. In the matched group (133 patients for each), the operative time, length of hospital stay, hospitalization expenses, cosmetic results, complications were assessed and compared between two groups.

RESULTS

At last follow-up, 39 tumors (29.3%) in the RFA group completely disappeared. Between the well-matched groups, no local recurrence, lymph node metastasis or distant metastases were detected in either group during the follow-up period. After matching, the operation time and hospitalization time in RFA group were shorter than those in surgery group (both P <  0.05). The average hospitalization expense of the patients in RFA group was cheaper than that in surgery group (P <  0.05). Moreover, the cosmetic score was found to be higher in RFA group than that observed in surgery group (P <  0.05).

CONCLUSIONS

RFA may be an effective and safe method for treating low-risk PTMC with a superior advantage of being low-cost and having a shorter operation time and hospital stay versus surgery.

Analysis of Curative Effect and Influencing Factors of N1 Stage Papillary Thyroid Micro-Carcinoma and Papillary Thyroid Non-Micro Carcinoma After Initial Radioactive Iodine Ablation Therapy

Objective

To compare the efficacy and influencing factors of initial radioactive iodine (RAI) ablation therapy for postoperative N1 stage papillary thyroid micro-carcinoma (PTMC) and papillary thyroid non-micro carcinoma (PTC), and to explore the necessity of RAI for N1 stage PTMC.

Methods

A retrospective analysis of patients with N1 stage papillary thyroid cancer who underwent RAI in our department from January 2018 to June 2019. According to the tumor diameter, papillary thyroid carcinoma was divided into PTMC group (≤ 1.0cm) with 129 patients and PTC group (> 1.0 cm) with 214 patients. According to the 2015 ATA guidelines, the patient’s treatment response was evaluated 6–8 months after discharge from the hospital: excellent response (ER), indeterminate response (IDR), biochemical incomplete response (BIR), and structural incomplete response (SIR). IDR, BIR, and SIR were classified into NER group. Chi-squared test, independent sample t-test, Mann–Whitney U test, and binary logistic regression analysis were used to compare the differences between PTMC and PTC patients.

Results

The ps-Tg of the PTMC group was significantly lower than that of the PTC group (P = 0.001), and the ER ratio of the PTMC group was higher (χ² = 5.445, P < 0.05). The ER ratio of PTMC patients in the N1a group was significantly higher than that of PTC patients (80%, 66.7%, χ² = 4.076, P < 0.05), while the ER ratio of PTMC in the N1b group was not significantly different from that of PTC. Gender, N stage, and ps-Tg were found to be independent factors of RAI treatment response.

Conclusion

The efficacy of the initial RAI of PTMC patients was significantly better than that of PTC patients. There was no significant difference in the efficacy of RAI between males with PTMC, N1b stage, ps-Tg ≥ 5.87ng/mL and PTC patients, which suggested that RAI is necessary for these patients.

Radiomics based on multiparametric MRI for extrathyroidal extension feature prediction in papillary thyroid cancer

BACKGROUND

To determine the predictive capability of MRI-based radiomics for extrathyroidal extension detection in papillary thyroid cancer (PTC) pre-surgically.

METHODS

The present retrospective trial assessed individuals with thyroid nodules examined by multiparametric MRI and subsequently administered thyroid surgery. Diagnosis and extrathyroidal extension (ETE) feature of PTC were based on pathological assessment. The thyroid tumors underwent manual segmentation, for radiomic feature extraction. Participants were randomized to the training and testing cohorts, at a ratio of 7:3. The mRMR (maximum correlation minimum redundancy) algorithm and the least absolute shrinkage and selection operator were utilized for radiomics feature selection. Then, a radiomics predictive model was generated via a linear combination of the features. The model's performance in distinguishing the ETE feature of PTC was assessed by analyzing the receiver operating characteristic curve.

RESULTS

Totally 132 patients were assessed in this study, including 92 and 40 in the training and test cohorts, respectively). Next, the 16 top-performing features, including 4, 7 and 5 from diffusion weighted (DWI), T2-weighted (T2 WI), and contrast-enhanced T1-weighted (CE-T1WI) images, respectively, were finally retained to construct the radiomics signature. There were 8 RLM, 5 CM, 2 shape, and 1 SZM features. The radiomics prediction model achieved AUCs of 0.96 and 0.87 in the training and testing sets, respectively.

CONCLUSIONS

Our study indicated that MRI radiomics approach had the potential to stratify patients based on ETE in PTCs preoperatively.

Clinical management of low-risk papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) is well known to have an indolent nature with an excellent prognosis. Surgery has been the standard treatment during the past several decades, with metastasis or recurrence being exceedingly rare. Active surveillance (AS) is a new risk-adapted approach alternative to surgery that involves just watching, but not giving any treatment unless needed, not addressing the tumor itself. The patients for whom AS is adopted spend their time "with tumors." In follow-up, it is possible that alarming factors such as tumor progression appear, causing anxiety about progression. Furthermore, endless follow-up is needed. However, considering the indolent nature and unfavorable events such as surgical complications caused by surgery, AS is a good management plan for selected PTMC patients. Decision making balancing between the prognosis and unfavorable events is needed for the treatment plan. Consideration of the factors and timing of surgical conversion is also needed. In this review article, how AS should be adopted as a new management option that is an alternative to surgery, which has been the absolute choice of treatment up to recently, is discussed. Concurrently, the characteristics of the two treatment strategies are reviewed, while introducing the background that explains how AS came to attention.

Effect of Prophylactic Central Lymph Node Dissection on Locoregional Recurrence in Patients with Papillary Thyroid Microcarcinoma

There is a consensus that central compartment lymph node dissection or modified radical lateral neck dissection should be performed in papillary thyroid microcarcinoma (PTMC) patients with lymph node metastases. Prophylactic central lymph node dissection (PCLND) in patients with clinically node-negative (cN0) PTMC to reduce locoregional recurrence (LRR) rate and improve prognosis remains controversial. The present study aimed to analyze the effect of PCLND on LRR and postoperative complications of PTMC in cN0 patients. We reviewed a cohort of patients with cN0 PTMC who underwent surgery between January 1997 and October 2019. The patients were divided into the PCLND and no lymph node dissection (NLND) groups. Kaplan-Meier curves were constructed to estimate 15-year locoregional recurrence-free survival rate of the two groups, and the difference was compared by the log-rank test. Three Cox regression models were performed to evaluate the correlation between PCLND and LRR. All patients underwent thyroidectomy, and 25 patients developed LRR; of whom, 23 underwent PCLND at initial surgery and 2 went without lymph node dissection. Cox regression analysis showed that PCLND had no effect on LRR. Postoperative hematoma and permanent recurrent laryngeal nerve injury did not occur in the NLND group, and their incidences were 0.5% and 0.3% in the PCLND group, respectively. PCLND had no significant correlation with LRR in patients with cN0 PTMC, and the absolute benefit for PTMC was small.

Recurrence Factors and Characteristic Trends of Papillary Thyroid Cancer over Three Decades

BACKGROUND

The prevalence of thyroid cancer is rising worldwide. Although thyroid cancer has a favorable prognosis, up to 20% of patients experienced recurrent disease during the follow-up period. The present study aimed to examine the trend of incidence and factors associated with recurrence and outcomes of papillary thyroid cancer (PTC) in Thai patients over the last 30 years.

METHODS

We reviewed the clinical data of all patients with PTC who were treated between 1987 and 2019 at Theptarin Hospital. Clinical characteristics, epidemic trend, factors associated with the persistence/recurrence of the disease, overall disease-specific survival rate, and overall disease-free survival rate were analysed.

RESULTS

A total of 235 patients with PTC who were registered between 1987 and 2019 were reviewed. The mean age was 42.5 ± 14.3 years, with a mean follow-up of 9.5 years. Papillary thyroid microcarcinoma (PTMC) was consistently increased and accounted for 21.4% (50/235) of total cases. The American Thyroid Association (ATA) risk stratification was high in 24% of all PTMCs in the last decade, and 16.0% of these patients experienced local recurrence during the follow-up period. Coexistence with Hashimoto's thyroiditis (HT) was found in one-fifth of the patients with PTC and was correlated with a low recurrence rate (HR: 0.16, P=0.013). Only age ≥55 years associated with the persistence/recurrence of the disease. The overall disease-free survival and disease-specific survival rates were 77.4% and 98.3%, respectively.

CONCLUSIONS

The prognosis of PTC is generally considered favorable. However, approximately one-fourth of patients with PTMC demonstrated more aggressive clinical behavior, particularly in the last decade of the study. Coexistence of HT contributed to a better prognosis.

Lymphocyte-to-monocyte ratio prior to radioiodine ablation in low- and intermediate-risk, papillary thyroid cancer

PURPOSE

We aimed to investigate inflammation indices based on preablation hematological parameter of the lymphocyte-to-monocyte ratio (LMR) to predict the clinical outcome in papillary thyroid cancer (PTC) patients with low- and intermediate-risk stratification.

METHODS

This retrospective study analyzed 772 patients with low- and intermediate-risk PTC who underwent total thyroidectomy followed by radioiodine therapy between July 2005 and July 2009 with a median of 10 years. Kaplan-Meier statistics were used to test differences in recurrence-free survival (RFS) between groups based on the optimal cutoff point of biomarkers identified using receiver operating characteristic curves.

RESULTS

With an optimal cutoff point of 7.05, 215 patients (29.8%) were classified as having low LMR and 557 patients (71.2%) were classified as having high LMR. High LMR was significantly associated with a prolonged RFS (hazard ratio [HR]: 2.048, 95% confidence interval [CI]: 1.062-4.359, p = 0.001). Multivariate analysis showed that low LMR (HR = 2.035, 95% CI: 1.011-4.095, p = 0.012), tumor size over 2 cm (HR = 2.762, 95% CI: 1.303-5.852, p = 0.008), and high preablative simulated thyroglobulin level over 10 ng/ml (HR = 7.826, 95% CI: 2.353-26.033, p < 0.001) were independent prognostic markers for worse RFS in the enrolled PTC patients.

CONCLUSIONS

LMR at the time of radioiodine therapy has comparable predictor for the clinical outcome with both tumor size and preablative simulated thyroglobulin level in low- to intermediate-risk PTC patients.

Completion Total Thyroidectomy Is Not Necessary for Papillary Thyroid Microcarcinoma with Occult Central Lymph Node Metastasis: A Long-Term Serial Follow-Up

Simple Summary

The necessity of completion total thyroidectomy is unclear in patients with papillary thyroid microcarcinoma (PTMC) with only pathological central lymph node metastasis (pCLNM). The aim of our study was to determine the necessity of completion total thyroidectomy after an initial surgery by comparing the prognosis according to the presence of pCLNM during a long-term follow-up. We retrospectively compared the pathological central lymph node (pCLN)-positive group of 165 patients who underwent thyroid lobectomy with the pCLN-negative group of 711 patients and found no difference between the two groups in the recurrence rate and disease-free survival rates. Therefore, PTMC patients who underwent thyroid lobectomy with prophylactic central compartment neck dissection and were diagnosed with pCLNM after surgery do not require completion total thyroidectomy.

Abstract

The necessity of completion total thyroidectomy in patients with papillary thyroid microcarcinoma (PTMC) and pathological central lymph node metastasis (pCLNM) who underwent thyroid lobectomy with central compartment neck dissection (CCND) is unclear. We determined the necessity of completion total thyroidectomy by retrospectively comparing the prognosis according to the presence of pCLNM during a long-term follow-up. We enrolled 876 patients with PTMC who underwent thyroid lobectomy with prophylactic CCND from January 1986 to December 2009. Patients were divided according to central lymph node (CLN) metastasis: 165 (18.8%) and 711 (81.2%) in the CLN-positive and CLN-negative groups, respectively. Medical records were reviewed retrospectively, and clinicopathologic characteristics and recurrence rates were analyzed. The CLN-positive group was associated with male sex (p = 0.001), larger tumor size (p < 0.001), and more microscopic capsular invasion (p < 0.001) compared with the CLN-negative group. There was no significant difference between the two groups’ recurrence (p = 0.133) or disease-free (p = 0.065) survival rates. Univariate and multivariate analyses showed no factors associated with tumor recurrence except male sex (hazard ratio = 3.043, confidence interval 1.117–8.288, p = 0.030). Patients who were diagnosed with pCLNM after undergoing thyroid lobectomy with prophylactic CCND do not require completion total thyroidectomy; however, frequent follow-up is necessary for patients with PTMC and pCLNM.

Association between BRAFV600E mutation and the clinicopathological features in incidental papillary thyroid microcarcinoma: A single-center study in Turkish patients

OBJECTIVE:

In this study, we evaluated the influences of BRAF^V600E mutation on clinicopathological features in incidentally found papillary thyroid microcarcinomas (PTMCs).

METHODS:

This retrospective cohort study included 72 patients with PTMC who underwent surgery from 2008 to 2012. The mean follow-up of the whole cohort was three years. DNA was isolated using QIAamp DNA formalin-fixed, paraffin-embedded (FFPE) tissue kit. BRAF gene was amplified by the polymerase chain reaction-restriction fragment length (PCR-RFL) polymorphism method with the following primers. The clinicopathologic features (age, gender, histologic subtype, tumor size, presence of tumor capsule, bilaterality, multifocality, extrathyroidal extension (ETE), thyroid capsular invasion, presence of Hashimoto’s thyroiditis, lymph node metastasis (LNM) and distant metastasis) were compared between the BRAF (+) and BRAF (-) patient groups.

RESULTS:

BRAF^V600E mutation was detected in 30 of the 72 patients (41.6%). The presence of the mutation was statistically significantly associated with classic variant (p=0.046), invasion of thyroid capsule (p=0.002) and absence of tumor capsule (p=0.003).

CONCLUSION:

Although incidental PTMCs positive for the BRAF^V600E mutation had more invasive behavior, the presence of the mutation was not associated with recurrences within three years of follow-up.

Clinical, Pathological, and Molecular Characteristics Correlating to the Occurrence of Radioiodine Refractory Differentiated Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Background: Recently, radioiodine refractory differentiated thyroid cancer (RR-DTC) has received increasing attention due to its poor prognosis. The roles of clinical, pathological, and molecular features in the development of RR-DTC remain controversial and require additional investigation. This study aimed to evaluate the association between these risk factors and the occurrence of RR-DTC.

Methods: We performed a systematic search for relevant literature following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) in PubMed, EMBASE, Medline, SCOPUS, and Web of Science up to the July 15, 2020. Observational studies that investigated the risk factors for RR-DTC were included. Fixed- or random-effects models were used to calculate pooled odds ratios (ORs) or mean differences (MD) with corresponding 95% confidence intervals.

Results: We included 13 eligible studies incorporating 1,431 cases, of which 603 were patients with RR-DTC. The pooled analysis indicated that four parameters significantly increased the risk of RR-DTC: extrathyroidal extension (ETE) (OR: 2.28, 95% CI: 1.43–3.64, I² = 14%), BRAF^V600E mutation (OR: 3.60, 95% CI: 1.74–7.46, I² = 69%), TERT promoter mutation (OR: 9.84, 95% CI: 3.60–26.89, I² = 61%) and high-risk histological subtype (OR: 1.94, 95% CI: 1.15–3.27, I² = 15%), including tall cell variant papillary thyroid carcinoma (PTC), sclerosing diffuse PTC, hobnail variant PTC, follicular thyroid carcinoma (FTC) (including Hürthle cell), and poorly differentiated thyroid carcinoma (PDTC). However, there was no statistical significance regarding sex, age, tumor size, multifocality, or lateral lymph node metastasis. Subgroup and sensitivity analyses were conducted to further confirm the robustness of the results.

Conclusions: Histological subtype, ETE, BRAF^V600E mutation, and TERT promoter mutation could be considered clinicopathological factors and biomarkers. They could assist in risk stratification, prognostic prediction, and individual therapy options for RR-DTC.

Predicting non-small-volume central lymph node metastases (>5 or ≥2 mm) preoperatively in cN0 papillary thyroid microcarcinoma without extrathyroidal extension

The ability to identify patients with aggressive papillary thyroid microcarcinoma (PTMC) from the low-risk patients is critical to planning proper management of PTMC. Lymph node metastases showed association with recurrence and low survival rate, especially in patients with >5 or ≥2 mm metastatic lymph nodes. Therefore, this study aimed to investigate the preoperatively predictive factors of non-small-volume (metastatic lymph nodes >5 or ≥2 mm in size) central lymph node metastases (NSVCLNM) in PTMC patients. A total of 420 patients with clinically node-negative (cN0) PTMC without extrathyroidal extension underwent thyroidectomy plus central neck dissection (CND) between January 2013 and December 2015, were retrospectively analyzed. Of the 420 patients, 33 (7.9%) had NSVCLNM. The 5-year recurrence-free survival was significantly less in cN0 PTMC patients with NSVCLNM, when compared with patients without NSVCLNM (80.8% vs 100%, P < .001). Multivariate logistic regression revealed age ≤36 years (P < .001), male sex (P = .002), ultrasonic tumor sizes of >0.65 cm (P < .001), and ultrasonic multifocality (P = .039) were independent predictive factors of NSVCLNM. A prediction equation (Y = 1.714 × age + 1.361 × sex + 1.639 × tumor size + 0.842 × multifocality -5.196) was developed, with a sensitivity (69.7%) and a specificity (84.0%), respectively, at an optimal cutoff point of -2.418. In conclusion, if the predictive value was >-2.418 according to the equation, immediate surgery including CND rather than active surveillance might be considered for cN0 PTMC patients.

BRAF Status in Papillary Microcarcinomas of the Thyroid Gland: a Brief Review

Papillary thyroid microcarcinoma (PTMC) is defined by the World Health Organization as papillary cancer measuring 10 mm or less in diameter. Generally, PTMC shows an indolent clinical behavior with a good prognosis, although a minority of PTMC is characterized by an aggressive course. However, efforts to identify this aggressive subset of PTMC after surgery remain inconclusive. Several oncogenic pathways have been identified in thyroid cancer and have been applied translationally to improve prognosis and clinical management. In particular, the BRAFV600E mutation was found more frequently in large, aggressive, recurrent and advanced tumors. We aimed at reviewing studies on BRAFV600E mutation as a prognostic factor in PTMC.

The importance of risk of neoplasm as an outcome in cytologic-histologic correlation studies on thyroid fine needle aspiration

BACKGROUND

The introduction of noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) altered the practice of thyroid pathology and reduced the risk of malignancy (ROM) associated with the indeterminate categories in the Bethesda system for reporting thyroid cytopathology (TBSRTC). It has been proposed that the evaluation of the risk of neoplasm (RON) is important in cytologic-histologic correlation studies.

METHODS

A total of 5224 thyroid aspirates were performed at our institution during an 8-year period. Of the 1475 cases (28%) with surgical follow-up, the histologic diagnoses comprised benign non-neoplastic (BNN, n = 669), follicular adenoma (FA, n = 188), NIFTP (n = 42), papillary microcarcinoma (PMC) (n = 223), and malignant neoplasm excluding PMC (n = 353). The RON was calculated to include neoplasia with low risk biologic behavior (FA, NIFTP, PMC) and malignant neoplasms. In contrast, the ROM was reserved for malignant neoplasms excluding PMC.

RESULTS

The RON for each TBSRTC category was: nondiagnostic (ND) 38.3%, benign 20.9%, atypia of undetermined significance/follicular lesion of undetermined significance (AUS/FLUS) 63.2%, follicular neoplasm or suspicious for follicular neoplasm (FN/SFN) 83.9%, suspicious for malignancy (SFM) 94%, and malignant 100%. The ROM excluding PMC was: ND 14%, benign 1.6%, AUS/FLUS 17.8%, FN/SFN 28.4%, SFM 84.4%, and malignant 99.5%.

CONCLUSIONS

The RON and ROM support the recommended management guidelines from TBSRTC for all categories, except for FN/SFN. Histopathologic follow-up of FN/SFN aspirates in our study contain a very high rate of neoplasm (83.9%), which might support the management preference of conservative surgery.

The Impact of BRAF Mutation on the Recurrence of Papillary Thyroid Carcinoma: A Meta-Analysis

Previous meta-analyses indicated that the BRAF V600E mutation was associated with an increased recurrence rate of papillary thyroid carcinoma (PTC). However, with recent publications of large cohort studies, the need for an updated meta-analysis increases. Therefore, we conducted a comprehensive meta-analysis to assess the impact of the BRAF V600E mutation on PTC recurrences. We performed a literature search using PubMed, SCOPUS, the Cochrane Database of Systematic Reviews, and the Web of Science Core Collection, from their inception to May 31, 2020. The relevant studies compared recurrence rates using the hazard ratio (HR) of BRAF mutations; 11 studies comprising 4674 patients were identified and included. Recurrence rates in patients with the BRAF V600E mutation were comparable with BRAF wild-type patients (HR 1.16, 95% CI 0.78–1.71), after adjustment for possible confounders. In subgroup analysis, both geographical region (HRs for America, Asia, and Europe were 2.16, 1.31 and 0.66, respectively) and tumor stage (HRs for stage I and II were 1.51 and 4.45, respectively) can affect the HRs of the BRAF mutation for recurrence. In conclusion, the BRAF mutation does not increase the risk of recurrences in patients with PTC. Differences in the geographical region or tumor stage should be considered when interpreting the impact of a BRAF mutation on recurrence.

Limitations of ultrasound in predicting bilaterality vs unilaterality of well-differentiated carcinoma of the thyroid

PURPOSE

The purpose of this study is to assess the efficacy of ultrasonography in the differentiation of a bilateral and a unilateral WDTC to help physicians decide on performing a total or a partial thyroidectomy.

MATERIALS AND METHODS

Retrospective chart review of all patients diagnosed with papillary thyroid carcinoma following a total thyroidectomy or a complete thyroidectomy between January 2013 and December 2015 at the Department of Otorhinolaryngology and Head and Neck Surgery in Soroka University Medical Center in southern Israel. The preoperative ultrasound images of the thyroid were compared to the final pathology in the contralateral lobe.

RESULTS

Seventy seven patients (77) were included in this study, There was no correlation between the sonography in the contralateral lobe and the malignancy on that side (p = 0.479). US had a 39% false negative rate and 69% false positive rate.

CONCLUSION

The patients with a well-differentiated carcinoma of the thyroid, a benign nodule detected sonographically in the contralateral lobe should not bear a high weight in decision making regarding the extent of surgery.

Predicting large-volume lymph node metastasis in the clinically node-negative papillary thyroid microcarcinoma: a retrospective study

OBJECTIVE

Large-volume lymph node metastasis (LNM) has been believed to be an important predictor for recurrence in papillary thyroid microcarcinoma (PTMC). However, the clinical predictors for large-volume LNM have yet to be established. This study aimed to determine clinical predictors for large-volume LNM in clinically node-negative PTMC.

METHODS

A total of 947 clinically N0 PTMC patients who received total thyroidectomy with lymph node dissection and radioiodine therapy were included. Based on the LNM status, they were divided into two groups: large-volume LNM and small-volume LNM including those patients without LNM. The association between age, gender and other clinical factors and large-volume LNM were investigated. The recurrence-free survival was also compared among these groups.

RESULTS

We found that male gender [odds ratio (OR) = 1.865, P = 0.015], young age (OR = 2.743, P < 0.001) and extrathyroid extension (OR = 5.352, P < 0.001) were independent predictors for high prevalence of large-volume LNM. Young (<40 years) and male patients tended to have large-volume LNM with the highest prevalence of 17.20%, whereas old (≥55 years) and female patients had the lowest prevalence of 2.02%. After median follow-up of 71 months, the recurrence rate was significantly higher for large-volume LNM compared with small-volume LNM (15.48 vs 0.72%, P < 0.05). Large-volume LNM status was significantly associated with decreased recurrence-free probability, while small-volume LNM had little effect on the recurrence-free survival.

CONCLUSIONS

This study showed that in clinically node-negative PTMC, young male patients had a greater incidence of large-volume LNM.

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.

Efficacy and Safety of Thermal Ablation Techniques for the Treatment of Primary Papillary Thyroid Microcarcinoma: A Systematic Review and Meta-Analysis

Background: The increased incidence of primary papillary thyroid microcarcinoma (PTMC) has led to increased research in the field of nonsurgical therapeutic options for those who refuse surgery or are at high risk for surgery. The study aimed at comprehensively evaluating the efficacy and safety of thermal ablation techniques for the treatment of PTMC via a systematic review and meta-analysis. Methods: The Pubmed MEDLINE and EMBASE databases were searched for studies reporting the efficacy and safety of thermal ablations (radiofrequency-, laser-, and microwave-ablations [RFA, LA, and MWA]) until August 10, 2019. A review of 105 potential papers identified 11 eligible papers, including 715 patients. The pooled proportions of complete disappearance and recurrence, and the pooled estimates of mean volume reduction and its rate of the treated PTMC were assessed by using random-effects modeling. The pooled proportions of overall and major complications were calculated. Subgroup analysis was performed according to the treatment modality. Between-study heterogeneity was explored by using χ² statistic for pooled estimates and inconsistency index I². Quality of the studies was evaluated by using the Risk of Bias Assessment Tool for Nonrandomized Studies. Results: The pooled proportions of complete disappearance and recurrence of PTMC were 57.6% [95% confidence interval (CI): 35.4-79.8] and 0.4% [95% CI: 0-1.1], respectively. The pooled estimates of mean volume reduction and its rate were 73.5 mm³ [52.4-94.6 mm³] and 98.1% [95% CI: 96.7-99.5], respectively. The pooled proportions of overall and major complications were 3.2% [95% CI: 1.1-5.2] and 0.7% [95% CI: 0-1.5], respectively. Significant between-study heterogeneity was observed for complete disappearance (p < 0.001, I²: 99%), mean volume reduction (p < 0.001, I²: 93%), and its rate (p < 0.001, I²: 86%). Subgroup analysis revealed heterogeneity of the complete disappearance proportion among the treatment modality (I² range: 95-100%). RFA showed the highest mean volume reduction rate (99.3%), followed by MWA (95.3%) and LA (88.6%) (p < 0.001). Conclusions: All thermal ablation techniques were effective and safe for the treatment of PTMC. However, each treatment modality had significant heterogeneity with respect to complete disappearance of PTMC. Compared with RFA and MWA, LA was less effective in reducing the volume of PTMC.

Predictive factors for central lymph node metastases in papillary thyroid microcarcinoma

Papillary thyroid microcarcinoma (PTMC) measures 1 cm or less in its longest dimension. The incidence of PTMC is increasing worldwide. Surgery is the primary treatment; however, prophylactic central lymph node dissection is controversial, and discrepancies between different guidelines have been noted. Routine prophylactic central lymph node dissection may result in hypoparathyroidism and recurrent laryngeal nerve injury in some patients without lymph node metastasis, while simple thyroidectomy may leave metastatic lymph nodes in high-risk patients. To selectively perform prophylactic lymph node dissections in high-risk patients, it is important to identify predictive factors for lymph node metastases in patients with PTMC. Several studies have reported on this, but their conclusions are not entirely consistent. Several clinicopathologic characteristics have been identified as risk factors for central lymph node metastases, and the most commonly reported factors include age, gender, tumor size and location, multifocality, bilaterality, extrathyroidal extension, and abnormal lymph node found using ultrasound. Here, we provide an overview of previous studies along with a favorable opinion on or against these factors, with the aim of increasing the understanding of this topic among the medical community. In addition, current opinions about prophylactic central lymph node dissection are reviewed and discussed.

Ultrasound-Guided Laser Ablation Versus Microwave Ablation for Patients With Unifocal Papillary Thyroid Microcarcinoma: A Retrospective Study

BACKGROUND AND OBJECTIVES

The objective of this study is to compare the efficacy and the safety of ultrasound-guided microwave ablation (MWA) and laser ablation (LA) for the treatment of papillary thyroid microcarcinoma (PTMC).

STUDY DESIGN/MATERIALS AND METHODS

A total of 67 patients with unifocal PTMC were studied retrospectively, including 33 cases who underwent MWA (MWA group) and 34 cases who received LA (LA group). The follow-up consisted of thyroid function tests, ultrasonography, contrast-enhanced ultrasonography (CEUS), and chest X-ray or computed tomography scan. The treatment response and complications were compared between the two groups.

RESULTS

The follow-up time for the MWA and LA group was 23.3 ± 4.4 and 22.8 ± 4.1 months, respectively. All the ablations were successfully performed as planned without complementary ablations, and it was confirmed by CEUS after treatment in both groups. It was observed that, at the last follow-up, the mean largest diameter decreased from 5.0 ± 1.4 mm to 0.1 ± 0.4 mm (MWA group) and from 4.5 ± 1.6 mm to 0.6 ± 1.2 mm(LA group) (P < 0.05 for both). The average volume reduced from 51.9 ± 40.8 to 0.2 ± 1.0 mm³ (MWA group) and from 38.5 ± 43.0 to 1.3 ± 3.8 mm³ (LA group) (P < 0.05 for both). The complication rates did not differ between the MWA group (9.1%) and the LA group (2.9%) (P > 0.05). No local recurrence or distant metastasis occurred in either group.

CONCLUSIONS

During the short-term follow-up period, ultrasound-guided MWA and LA were both safe and effective methods in treating patients with unifocal PTMC. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Ultrasound-Guided Radiofrequency Ablation Versus Surgery for Low-Risk Papillary Thyroid Microcarcinoma: Results of Over 5 Years' Follow-Up

Background: Papillary thyroid microcarcinoma (PTMC) typically carries an excellent prognosis regardless of the treatment option pursued. Radiofrequency ablation (RFA) for thyroid disease has been utilized for benign lesions and in patients who are poor surgical candidates for thyroid cancers with compression symptoms, but the efficacy and limitations of RFA as first-line therapy for PTMC has not been described in adequate detail. The purpose of our study was to investigate RFA versus thyroidectomy in terms of efficacy, oncologic outcomes, quality of life, complications, and costs over a 5-year period of follow-up. Methods: From January 2013 to November 2013, 174 consecutive patients with an isolated, solitary intrathyroidal PTMC were identified in a Chinese teaching hospital. Those with more aggressive or advanced PTMCs were not included. Ninety-four patients elected RFA and 80 patients elected surgery for treatment of these PTMC. Nodules were confirmed to be PTMC without an aggressive histological type by core needle biopsy in the RFA group and by final surgical pathology in the surgery group. The extent of surgery was decided based on patient preferences in consultation with the surgeons. Of all the patients, 58 (72.5%) underwent lobectomy, 22 (27.5%) underwent total thyroidectomy, and 53 (66.3%) underwent lymph node dissection. Pre- and post-treatment variables were compared between the two groups, including demographics, tumor characteristics, treatment, local tumor progression, lymph node metastasis, distant metastasis, local recurrence, complications, and quality-of-life findings. Results: Patient-specific variables were similar between groups, as were oncologic outcomes after 5 years of follow-up. When compared with RFA, surgery took longer, had a longer hospitalization time, and was costlier (all p < 0.001). The surgery group had three complications, with 2 (2.5%) permanent recurrent laryngeal nerve injuries and 1 (1.3%) case of permanent hypoparathyroidism, while none was reported in the RFA group (p = 0.095). The surgery group had a lower post-treatment thyroid-related quality of life. Conclusions: For carefully selected low-risk intrathyroidal PTMC, RFA was not oncologically inferior to open surgery, and it was associated with a higher quality of life and lower overall costs.

Dynamic contrast-enhanced MRI model selection for predicting tumor aggressiveness in papillary thyroid cancers

The purpose of this study was to identify the optimal tracer kinetic model from T1 -weighted dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) data and evaluate whether parameters estimated from the optimal model predict tumor aggressiveness determined from histopathology in patients with papillary thyroid carcinoma (PTC) prior to surgery. In this prospective study, 18 PTC patients underwent pretreatment DCE-MRI on a 3 T MR scanner prior to thyroidectomy. This study was approved by the institutional review board and informed consent was obtained from all patients. The two-compartment exchange model, compartmental tissue uptake model, extended Tofts model (ETM) and standard Tofts model were compared on a voxel-wise basis to determine the optimal model using the corrected Akaike information criterion (AICc) for PTC. The optimal model is the one with the lowest AICc. Statistical analysis included paired and unpaired t-tests and a one-way analysis of variance. Bonferroni correction was applied for multiple comparisons. Receiver operating characteristic (ROC) curves were generated from the optimal model parameters to differentiate PTC with and without aggressive features, and AUCs were compared. ETM performed best with the lowest AICc and the highest Akaike weight (0.44) among the four models. ETM was preferred in 44% of all 3419 voxels. The ETM estimates of Ktrans in PTCs with the aggressive feature extrathyroidal extension (ETE) were significantly higher than those without ETE (0.78 ± 0.29 vs. 0.34 ± 0.18 min-1 , P = 0.005). From ROC analysis, cut-off values of Ktrans , ve and vp , which discriminated between PTCs with and without ETE, were determined at 0.45 min-1 , 0.28 and 0.014 respectively. The sensitivities and specificities were 86 and 82% (Ktrans ), 71 and 82% (ve ), and 86 and 55% (vp ), respectively. Their respective AUCs were 0.90, 0.71 and 0.71. We conclude that ETM Ktrans has shown potential to classify tumors with and without aggressive ETE in patients with PTC.

BRAF V600E status may facilitate decision-making on active surveillance of low-risk papillary thyroid microcarcinoma

INTRODUCTION

Conservative active surveillance has been proposed for low-risk papillary thyroid microcarcinoma (PTMC), defined as ≤1.0 cm and lacking clinical aggressive features, but controversy exists with accepting it as not all such PTMCs are uniformly destined for benign prognosis. This study investigated whether BRAF V600E status could further risk stratify PTMC, particularly low-risk PTMC, and can thus help with more accurate case selection for conservative management.

METHODS

This international multicenter study included 743 patients treated with total thyroidectomy for PTMC (584 women and 159 men), with a median age of 49 years (interquartile range [IQR], 39-59 years) and a median follow-up time of 53 months (IQR, 25-93 months).

RESULTS

On overall analyses of all PTMCs, tumour recurrences were 6.4% (32/502) versus 10.8% (26/241) in BRAF mutation-negative versus BRAF mutation-positive patients (P = 0.041), with a hazard ratio (HR) of 2.44 (95% CI (confidence interval), 1.15-5.20) after multivariate adjustment for confounding clinical factors. On the analyses of low-risk PTMC, recurrences were 1.3% (5/383) versus 4.3% (6/139) in BRAF mutation-negative versus BRAF mutation-positive patients, with an HR of 6.65 (95% CI, 1.80-24.65) after adjustment for confounding clinical factors. BRAF mutation was associated with a significant decline in the Kaplan-Meier recurrence-free survival curve in low-risk PTMC.

CONCLUSIONS

BRAF V600E differentiates the recurrence risk of PTMC, particularly low-risk PTMC. Given the robust negative predictive value, conservative active surveillance of BRAF mutation-negative low-risk PTMC is reasonable whereas the increased recurrence risk and other well-known adverse effects of BRAF V600E make the feasibility of long-term conservative surveillance uncertain for BRAF mutation-positive PTMC.

Isthmusectomy in selected patients with well-differentiated thyroid carcinoma

BACKGROUND

Isthmusectomy in the treatment of well-differentiated thyroid carcinoma (WDTC) is controversial. In this study, we analyze the outcomes of WDTC managed by isthmusectomy alone.

METHODS

Forty-three patients treated with isthmusectomy alone were identified from an institutional database of 6259 surgically treated patients with WDTC. Patient and tumor characteristics were analyzed. Disease-specific survival (DSS) and recurrence-free survival (RFS) were calculated using the Kaplan-Meier method.

RESULTS

The pT classification was T1 for 41 and T2 for two patients. All were clinical N0, but 10 pts were pN1a. Using the American Thyroid Association risk stratification system, 9 patients were low-risk and 22 were intermediate-risk. One patient developed local recurrence, and two developed regional lymph node metastases; the 5- and 10-year DSS was 100.0%. The 5- and 10-year RFS was 93.1%.

CONCLUSIONS

Isthmusectomy alone is an acceptable procedure in selected patients with low- and intermediate-risk WDTC limited to the isthmus.

Population-based study evaluating and predicting the probability of death resulting from thyroid cancer among patients with papillary thyroid microcarcinoma

BACKGROUND

Papillary thyroid microcarcinoma (PTMC) is an indolent carcinoma. The cumulative incidence of death from patients with PTMC and the nomogram built based on the competing risks model have not been described.

METHODS

Patients diagnosed with PTMC were selected from the Surveillance, Epidemiology, and End Results (SEER) program (1983-2015). Cumulative incidence function was utilized to calculate the likelihood of death resulting from thyroid cancer. Gray's test was conducted to examine the difference in the cumulative incidence of death between groups. A proportional subdistribution hazard model was constructed and we further built a nomogram to quantify the likelihood of death using the model. A 10-fold cross-validation procedure was adopted to validate the model.

RESULTS

A total of 46 662 patients diagnosed with PTMC were included. The median follow-up time was 81 months (range, 1 to 407 months). The 5-year, 10-year, and 20-year probabilities of death from thyroid carcinoma were 0.3%, 0.6%, and 1.4%, respectively. The age at diagnosis, sex, tumor extension, and lymph node involvement were related to the cumulative incidence of death. A proportional subdistribution hazard model was developed. The performance of the model was good. A nomogram was built based on the model to predict the likelihood of death in patients with PTMC.

CONCLUSION

The survival rate of patients with PTMC is excellent. The nomogram constructed based on the well-performed competing risks model is helpful for both patients and clinicians.

Risk factors for high-volume lymph node metastases in cN0 papillary thyroid microcarcinoma

Background

Lymph node metastasis (LNM) often occurs in clinical lymph node negative (cN0) papillary thyroid microcarcinoma (PTMC). The risk factors for LNM, especially for high-volume LNM, were investigated in this study.

Methods

The medical records of 1,974 consecutive PTMC patients admitted to the Peking Union Medical College Hospital (PUMCH) from 2013 to 2015 were reviewed. Their clinicopathological features were collected. Univariate and multivariate analyses were performed to identify the risk factors for LNM/high-volume LNM.

Results

Of all the patients, cervical lymph node metastases were detected in 690 patients (34.95%), and high-volume LNM was detected in 75 patients (3.80%). The results of univariate analysis revealed that sex, age, chronic thyroiditis, multifocality, and tumor diameter were significantly correlated with LNM (P<0.05) and that sex, age, multifocality, and tumor diameter were significantly correlated with high-volume LNM (P<0.05). Multivariate logistic regression analysis demonstrated that male sex [odds ratio (OR) =1.657, P<0.001], multifocality (OR =1.601, P<0.001), and tumor diameter >0.5 cm (OR =1.770, P<0.001) were independent risk factors for LNM; age of 40-59 years old (OR =0.427, P<0.001), age ≥60 years old (OR =0.291, P<0.001), and chronic thyroiditis (OR =0.562, P<0.001) were independent protective factors for LNM. For high-volume LNM, male sex (OR =2.250, P=0.002), tumor diameter >0.5 cm (OR =3.664, P=0.013) and multifocality (OR =2.034, P=0.004) were independent risk factors, whereas age ≥40 years old (OR =0.240, P<0.001) was an independent protective factor.

Conclusions

Lymph node metastases are common in cN0 PTMC, whereas high-volume LNM is rare. Active surveillance may be reasonable for patients with tumor diameter ≤0.5 cm, age ≥40 years old, female sex and isolated lesions.

Clinical Analysis of Pediatric Thyroid Cancer: A Single Medical Institution Experience of 18 Years

OBJECTIVE

The incidence of pediatric thyroid cancer is relatively low compared to the disease in adults. This study aims to present the data in our institution on pediatric thyroid cancer patients, with particular emphasis on the risk factors of recurrence together with treatment outcomes.

SUBJECTS AND METHODS

Between January 2000 and July 2018, patients <20 years who were diagnosed with thyroid carcinoma and primarily treated with surgery at a major large-volume tertiary medical center specializing in thyroid cancer were enrolled. A total of 83 patients were eligible for this study.

RESULTS

The majority of the studied patients were girls and adolescents (age ≥13 years). Papillary thyroid carcinoma (PTC) was the most common pathology (n = 74). PTC tumors >1 cm showed higher rate of lymph node metastasis and extrathyroidal extension than tumors ≤1 cm. All patients survived with nine PTC patients who displayed treatment failure. Age, tumor size, multifocality, lateral lymph node metastasis, and postoperative thyroglobulin levels were significant prognosticators for disease recurrence.

CONCLUSION

Pediatric thyroid cancer is relatively rare and should be considered a specific disease entity with respect to the thyroid cancer in adults, since there are several distinctive characteristics.

FACTORS INFLUENCING THE SUCCESSFUL MAINTENANCE OF EUTHYROIDISM AFTER LOBECTOMY IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA: A SINGLE-CENTER STUDY

Objective: This study aimed to evaluate factors influencing the successful maintenance of postoperative euthyroidism in patients who did not undergo immediate thyroid hormone replacement after lobectomy for papillary thyroid microcarcinoma (PTMC). Methods: From September 2015 to June 2017, 186 patients underwent lobectomy for PTMC in our hospital. Patients taking medications for hypothyroidism and hyperthyroidism before and after lobectomy were excluded. Multiple parameters, including sex, age, pre-operative free thyroxine (T4), thyroid-stimulating hormone (TSH), thyroglobulin (TG), and thyroid autoantibody levels, body mass index (BMI), postoperative histopathology of the thyroid gland, remnant thyroid gland volume, and session number of levothyroxine discontinuation were retrospectively evaluated. These factors were compared between groups based on the maintenance of postoperative euthyroidism. Results: In 88 of the 175 patients (50.3%), postoperative euthyroidism was successfully maintained without thyroid hormone replacement during the first year after lobectomy. There were significant differences in sex (P = .003), pre-operative TSH levels (P = .002), and histopathology of the thyroid gland (P = .035) between the groups showing maintenance success and failure. The group showing successful maintenance had a higher percentage of male patients, lower levels of pre-operative TSH, and normal parenchymal histology of the thyroid gland. However, there were no significant between-group differences in age, pre-operative free T4, TG, and thyroid autoantibody levels, BMI, remnant thyroid gland volume, and session number of levothyroxine discontinuation. Conclusion: Patient sex, pre-operative TSH levels, and histopathology of the thyroid gland may influence the maintenance of postoperative euthyroidism after lobectomy. Abbreviations: BMI = body mass index; PTMC = papillary thyroid microcarcinoma; RR = reference range; T4 = thyroxine; TFT = thyroid function test; TG = thyroglobulin; TSH = thyroid-stimulating hormone.

Efficacy of apparent diffusion coefficient in predicting aggressive histological features of papillary thyroid carcinoma

PURPOSE

We aimed to evaluate preoperative diffusion-weighted magnetic resonance imaging (DWI) for predicting aggressive histological features in papillary thyroid cancer (PTC).

METHODS

This prospective study included 141 PTC patients, who underwent DWI prior to thyroidectomy; 88 patients with 88 PTC lesions were finally analyzed. Multiple comparisons of mean and minimum apparent diffusion coefficient (ADC) values (ADCmean and ADCmin) and ADC of the solid component (ADCsolid) between the lowly aggressive PTC, highly aggressive PTC without hobnail, and hobnail variant PTC groups were performed by one-way ANOVA or the Welch test. The nonparametric Kruskal-Wallis H-test was used to assess lesion size differences. Receiver-operating characteristic (ROC) curve analysis was also performed.

RESULTS

ADC values in the lowly aggressive PTC group were found to be significantly higher than those in the highly aggressive PTC without hobnail group (ADCmean: 1.35±0.20×10-3 mm2/s vs. 1.16±0.17×10-3 mm2/s, P = 0.003; ADCmin: 1.10±0.17×10-3 mm2/s vs. 0.88±0.16×10-3 mm2/s, P < 0.001; ADCsolid: 1.26±0.23×10-3 mm2/s vs. 1.04±0.17×10-3 mm2/s, P < 0.001). No significant differences for the ADCmean, ADCmin, and ADCsolid were observed between the lowly aggressive and hobnail variant PTC groups (all P > 0.05). Lesion sizes in the hobnail variant PTC group was significantly elevated compared with the lowly aggressive PTC group (2.19±1.21 cm vs. 0.93±0.37 cm, P < 0.001). Areas under the curves (AUCs) for ADCmean, ADCmin, and ADCsolid between the lowly aggressive PTC and highly aggressive PTC group without hobnail were 0.758, 0.851, and 0.787, respectively. The AUC for size between the lowly aggressive and hobnail variant PTC group was 0.896.

CONCLUSION

ADCmin from DWI could potentially provide quantitative information to differentiate lowly aggressive PTC from highly aggressive PTC lesions without hobnail variants.