Microcarcinoma of the thyroid gland: the Gustave-Roussy Institute experience

Development and Validation of a Computed Tomography-Based Radiomics Nomogram for the Preoperative Prediction of Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

RATIONALE AND OBJECTIVES

This study aims to develop and validate a computed tomography (CT)-based radiomics nomogram for pre-operatively predicting central lymph node metastasis (CLNM) in patients with papillary thyroid microcarcinoma (PTMC) and explore the underlying biological basis by using RNA sequencing data.

METHODS

This study trained 452 PTMC patients across two hospitals from January 2012 to December 2020. The sets were randomly divided into the training (n = 339), internal test (n = 86), external test (n = 27) sets. Radiomics features were extracted from primary lesion's pre-operative CT images for each patient. After screening for features, five algorithms such as K-nearest neighbor, logistics regression, linear-support vector machine (SVM), Gaussian SVM, and polynomial SVM were used to establish the radiomics models. The performance of these five algorithms was evaluated and compared directly to radiologist's interpretation (CT-reported lymph node status). The radiomics signature score (Rad-score) was generated using a linear combination of the selected features. By combining the clinical risk factors and Rad score, a radiomics nomogram was established and compared with Rad-score and clinical model. The performance of the nomogram was evaluated based on the receiver operating characteristic (ROC) curve, calibration curve, and the decision curve analysis (DCA). The potential biological basis of nomogram was revealed by performing genetic analysis based on the RNA sequencing data.

RESULTS

A total of 25 radiomic features were ultimately selected to train the machine learning models, and the five machine learning models outperformed the radiologists' interpretation by achieving area under the ROC curves (AUCs) ranging from 0.606 to 0.730 in the internal test set. By incorporating the Rad score and clinical risk factors (sex, age, tumor-diameter, and CT-reported lymph node status), this nomogram achieved AUCs of 0.800 and 0.803 in the internal and external test set, which were higher than that of the Rad-score and clinical model, respectively. Calibration curves and DCA also showed that the nomogram had good performance. As for the biological basis exploration, in patients predicted by nomogram to be PTC patients with CLMN, 109 genes were dysregulated, and some of them were associated with pathways and biological processes such as tumor angiogenesis.

CONCLUSION

This radiomics nomogram successfully identified CLNM on pretreatment imaging across multiple institutions, exceeding the diagnostic ability of radiologists and had the potential to be integrated into clinical decision making as a non-invasive pre-operative tool.

Papillary Thyroid Microcarcinoma: Differences between Lesions in Incidental and Nonincidental Settings-Considerations on These Clinical Entities and Personal Experience

Papillary thyroid microcarcinoma (PTMC) represents 35-40% of all papillary cancers; it is defined as a nodule ≤ 10 mm at the time of histological diagnosis. The clinical significance of PTMC is still controversial, and it may be discovered in two settings: incidental PTMC (iPTMC), in which it is identified postoperatively upon histological examination of thyroid specimens following thyroid surgery for benign disease, and nonincidental PTMC (niPTMC), in which it is diagnosed before surgery. While iPTMC appears to be related to mild behavior and favorable clinical outcomes, niPTMC may exhibit markers of aggressiveness. We retrospectively review our experience, selecting 54 PTMCs: 28 classified as niPTMC (52%) and 26 classified as iPTMC (48%). Patients with niPTMC showed significant differences, such as younger age at diagnosis (p < 0.001); a lower male/female ratio (p < 0.01); a larger mean nodule diameter (p < 0.001); and a higher rate of aggressive pathological findings, such as multifocality, capsular invasion and/or lymphovascular invasion (p = 0.035). Other differences found in the niPTMC subgroup included a higher preoperative serum TSH level, higher hospital morbidity and a greater need for postoperative iodine ablation therapy (p < 0.05), while disease-free long-term survival did not differ between subgroups (p = 0.331) after a mean follow-up (FU) of 87 months, with one nodal recurrence among niPTMCs. The differences between iPTMC and niPTMC were consistent: patients operated on for total thyroidectomy and showing iPTMC can be considered healed after surgery, and follow-up should be designed to properly calibrate hormonal supplementation; conversely, niPTMC may sometimes exhibit aggressive behavior, and so the FU regimen should be closer and aimed at early detection of cancer recurrence.

Diagnosis of thyroid micronodules on ultrasound using a deep convolutional neural network

To assess the performance of deep convolutional neural network (CNN) to discriminate malignant and benign thyroid nodules < 10 mm in size and compare the diagnostic performance of CNN with those of radiologists. Computer-aided diagnosis was implemented with CNN and trained using ultrasound (US) images of 13,560 nodules ≥ 10 mm in size. Between March 2016 and February 2018, US images of nodules < 10 mm were retrospectively collected at the same institution. All nodules were confirmed as malignant or benign from aspirate cytology or surgical histology. Diagnostic performances of CNN and radiologists were assessed and compared for area under curve (AUC), sensitivity, specificity, accuracy, positive predictive value, and negative predictive value. Subgroup analyses were performed based on nodule size with a cut-off value of 5 mm. Categorization performances of CNN and radiologists were also compared. A total of 370 nodules from 362 consecutive patients were assessed. CNN showed higher negative predictive value (35.3% vs. 22.6%, P = 0.048) and AUC (0.66 vs. 0.57, P = 0.04) than radiologists. CNN also showed better categorization performance than radiologists. In the subgroup of nodules ≤ 5 mm, CNN showed higher AUC (0.63 vs. 0.51, P = 0.08) and specificity (68.2% vs. 9.1%, P < 0.001) than radiologists. Convolutional neural network trained with thyroid nodules ≥ 10 mm in size showed overall better diagnostic performance than radiologists in the diagnosis and categorization of thyroid nodules < 10 mm, especially in nodules ≤ 5 mm.

Predictive Factors of Recurrence of Papillary Thyroid Microcarcinomas: Analysis of 2,538 Patients

Introduction  The incidence of papillary thyroid microcarcinoma (PTMC) has increased, and its treatment remains controversial.

Objective  To identify the clinical and pathological factors predictive of tumor recurrence.

Methods  We retrospectively analyzed 2,538 consecutive patients treated for PTMC, most submitted to total thyroidectomy (98%) followed by radioactive iodine (RAI) ablation (51.7%) at a cancer center from 1996 to 2015. The patients were stratified according to the American Thyroid Association (ATA) risk categories (low, intermediate, or high), and the clinicopathological features were evaluated by multivariate Cox regression analysis to identify independent prognostic factors for recurrence.

Results  After a mean follow-up of 58 months (range: 3 to 236.5 months), tumor recurrence was diagnosed in 63 (2.5%) patients, mostly in the lymph nodes. Distant metastasis occurred in 2 (0.1%) patients. There were no cancer-related deaths. The multivariate analysis showed that age < 55 years ( p  = 0.049; hazard ratio [HR]: 2.54; 95% confidence interval [95%CI]: 0.95 to 0.99), multifocality ( p  = 0.032; HR: 1.76; 95%CI: 1.05 to 2.96), and the presence of lymph-node metastasis ( p  < 0.001; HR: 3.69; 95%CI: 2.07–6.57) were independent risk factors for recurrence. Recurrence was observed in 29 (1.5%) out of 1,940 low-risk patients, 32 (5.4%) out of 590 intermediate-risk patients, and in 2 (25%) out of 8 high-risk patients.

Conclusions  The prognosis of PTMC is excellent, favoring a conservative treatment for most patients. Age < 55 years, multifocality, and node metastasis at diagnosis, as well the ATA staging system effectively predict the risk of recurrence. The presence of these risk factors can help identify patients who should be considered for more aggressive management and more frequent follow-up.

Management of Low-Risk Thyroid Cancers: Is Active Surveillance a Valid Option? A Systematic Review of the Literature

Thyroid cancer is the most common endocrine malignancy, representing 2.9% of all new cancers in the United States. It has an excellent prognosis, with a five-year relative survival rate of 98.3%.Differentiated Thyroid Carcinomas (DTCs) are the most diagnosed thyroid tumors and are characterized by a slow growth rate and indolent course. For years, the only approach to treatment was thyroidectomy. Active surveillance (AS) has recently emerged as an alternative approach; it involves regular observation aimed at recognizing the minority of patients who will clinically progress and would likely benefit from rescue surgery. To better clarify the indications for active surveillance for low-risk thyroid cancers, we reviewed the current management of low-risk DTCs with a systematic search performed according to a PRISMA flowchart in electronic databases (PubMed, Web of Science, Scopus, and EMBASE) for studies published before May 2021. Fourteen publications were included for final analysis, with a total number of 4830 patients under AS. A total of 451/4830 (9.4%) patients experienced an increase in maximum diameter by >3 mm; 609/4830 (12.6%) patients underwent delayed surgery after AS; metastatic spread to cervical lymph nodes was present in 88/4213 (2.1%) patients; 4/3589 (0.1%) patients had metastatic disease outside of cervical lymph nodes. Finally, no subject had a documented mortality due to thyroid cancer during AS. Currently, the American Thyroid Association guidelines do not support AS as the first-line treatment in patients with PMC; however, they consider AS to be an effective alternative, particularly in patients with high surgical risk or poor life expectancy due to comorbid conditions. Thus, AS could be an alternative to immediate surgery for patients with very-low-risk tumors showing no cytologic evidence of aggressive disease, for high-risk surgical candidates, for those with concurrent comorbidities requiring urgent intervention, and for patients with a relatively short life expectancy.

The role of the size in thyroid cancer risk stratification

Only a minority of cases of differentiated thyroid carcinoma (DTC) have a poor clinical outcome. Clinical outcomes and molecular aspects were assessed in: 144 DTC ≤ 40 mm without distant metastases (group 1); 50 DTC > 40 mm without distant metastases (group 2); and 46 DTC with distant metastases (group 3). Group 3 had a worse outcome than the other two groups: during the follow-up, patients more frequently had persistent disease, died, or underwent further treatment. The outcomes did not differ between groups 1 and 2. Group 3 had a higher prevalence of TERT promoter mutations than group 2 (32.6% vs 14%). Group 1 had a higher frequency of BRAF mutations than groups 2 or 3 (61.1% vs 16.0% and 26.1%, respectively), while RAS mutations were more common in group 2 than in groups 1 and 3 (16.0% vs 2.1% and 6.5%, respectively). Groups 1 and 2 shared the same outcome, but were genetically distinct. Only lymph node involvement, distant metastases, older age and (among the molecular markers) TERT promoter mutations were independent predictors of a worse outcome. Metastatic DTC had the worst outcome, while the outcome was identical for large and small non-metastatic DTC, although they showed different molecular patterns. TERT promoter mutations emerged as an independent factor pointing to a poor prognosis.

Associations of BRAF V600E, clinical pathology and imaging factors with the recurrence rate of papillary thyroid microcarcinoma

In the present study, the recurrence rate of papillary thyroid microcarcinoma (PTMC) was assessed by analyzing postoperative follow-up data of affected patients and its associations with BRAF V600E, clinical pathology and imaging factors were explored. A total of 506 patients with PTMC were selected who underwent surgery from January 2014 to March 2016. The maximal diameter of thyroid nodules was ≤1 cm and all patients who underwent BRAF V600E testing and evaluation for lymph node metastasis. Postoperatively, each patient was regularly followed up to detect recurrence. Categorical variables were comparatively analyzed using univariate Cox linear regression analysis to screen for protective and adverse factors influencing recurrence of PTMC. A stepwise Cox proportional hazards regression model analysis was performed to explore risk factors affecting recurrence. Among the 506 patients, 477 were followed up, 29 were lost to follow-up and 26 patients experienced recurrence. The 5-year recurrent rate of PTMC was 5.45%. The univariate Cox regression analysis indicated that PTMC recurrence was influenced by BRAF V600E, sex, multifocality, capsular invasion and lateral cervical lymph node metastasis (P<0.05), but not by age, tumor location on the thyroid, size, single central lymph node metastasis, distant metastasis and operative approach (P>0.05). The significant factors associated with recurrent PTMC were subjected to stepwise multivariate Cox proportional hazards regression model analysis and the results indicated that BRAF V600E, sex, multifocality and lateral cervical lymph node metastasis were independent factors influencing recurrence in patients with PTMC, with a statistically significant difference (P<0.05). In conclusion, BRAF V600E, sex, multifocality and lateral cervical lymph node metastasis are independent risk factors for recurrent PTMC.

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.

Impact of thyroid ultrasonography combined ultrasound-guided fine-needle aspiration biopsy in detection thyroid microcarcinoma: A protocol of systematic review

BACKGROUND

This study aims to explore the accuracy of thyroid ultrasonography (TUS) combined ultrasound-guided fine-needle aspiration biopsy (UGFNAB) for detection of thyroid microcarcinoma (TMC).

METHODS

A comprehensive search in PUBMED, EMBASE, Cochrane Library, Web of Science, Scopus, Chinese Biomedical Literature Database, and China National Knowledge Infrastructure from the beginning to the June 1, 2020 without language and publication status limitations. Two authors will independently perform articles identification, data extraction and assessment of study quality. Any disagreements will be resolved by discussion with a third author. We will carry out study quality evaluation using Quality Assessment of Diagnostic Accuracy Studies tool, and will employ statistical analysis using RevMan V.5.3 and Stata V.12.0 softwares.

RESULTS

We will summarize current evidence to investigate the accuracy of TUS combined UGFNAB in detection of TMC.

CONCLUSION

The findings of this study may provide helpful evidence of TUS combined UGFNAB in detection of TMC.

STUDY REGISTRATION

INPLASY202070048.

Unilateral Multifocality and Bilaterality Could Be Two Different Multifocal Entities in Patients with Papillary Thyroid Microcarcinoma

OBJECTIVE

Multifocality within an affected lobe (unilateral multifocality) or two lobes (bilaterality) is commonly denoted as multifocality without differentiation. Recently, there has been molecular evidence indicating that unilateral multifocality and bilaterality could be two different entities. However, few studies concerning the comparison between these two different multifocality entities have been reported.

DESIGN

A retrospective cohort study.

METHODS

From 2010 to 2013, in total, 949 consecutive patients with papillary thyroid microcarcinoma (PTMC) were enrolled and further divided into four groups based on multifocality status. Unilateral multifocality and bilaterality were analyzed by binary logistic regression along with other clinicopathological factors.

RESULTS

Unilateral multifocality, instead of bilaterality, was correlated with central neck metastasis (CNM) in both univariate and multivariate analyses. Group IV (unilateral multifocality and bilaterality coexist) had the highest CNM rate. Group III (unilateral multifocality) had a higher CNM rate than group II (bilaterality, single lesion in each lobe), with a significant difference (p = 0.032). Similar lateral neck metastasis tendency was observed among the four groups. In the multivariate analysis, only unilateral multifocality and bilaterality which coexisted were correlated with CNM. Moreover, 9 cases had a recurrence, with the recurrence rate ranking top in group IV (3.6%), second in group III (2.8%), and third in group II (1.2%). The difference was significant (p = 0.021).

CONCLUSION

Unilateral multifocality and bilaterality could be two different multifocal entities in patients with PTMC. Unilateral multifocality serving as a prognostic factor indicated a worse prognosis than bilaterality on neck metastasis. When the two factors coexisted in PTMC, patients had the highest risk of CNM and possibly local recurrence compared with those with either risk factor alone.

Papillary thyroid microcarcinoma presenting as a metastasis to the brain

The brain is a particularly rare site of metastasis from papillary microcarcinoma, with only few cases described in the literature. We present a case of 59-year-old man who presented with seizures and dysphasia due to left frontal lobe cystic mass, which was excised and turned out on histopathology to be of thyroid origin. Total thyroidectomy was performed and histology showed multifocal papillary microcarcinoma with the largest focus of 3mm with no other adverse features. The patient had ablative radioactive iodine postoperatively, with subsequent exit scan showing no uptake in the brain. Follow-up brain magnetic resonance imaging showed continuous regression of the surgical cavity. Although rare, such cases should be aggressively treated and followed up over the long term, because of reported associated high mortality.

Recurrence following hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma

BACKGROUND

This study evaluated the incidence, patterns and risk factors for recurrence after hemithyroidectomy in patients with low- and intermediate-risk papillary thyroid carcinoma (PTC), and verified the predictive role of the risk staging systems in current use.

METHODS

The clinicopathological characteristics and risk categories were analysed according to recurrence in patients who underwent hemithyroidectomy for low- and intermediate-risk conventional PTC, and were followed up for at least 24 months. Five risk staging systems were used to stratify risk: the 2015 American Thyroid Association (ATA) system; Age, Metastases, Extent and Size (AMES) system; Metastases, Age, Complete resection, Invasion and Size (MACIS) system; Grade, Age, Metastases, Extent and Size (GAMES) system; and the eighth AJCC system.

RESULTS

The study included 561 patients; 93·9 per cent of the study population (527 of 561) had a papillary thyroid microcarcinoma 1 cm or smaller in size. At a mean follow-up of 83 months, 25 patients (4·5 per cent) had recurrence; among these patients, 23 (92%) presented with a remaining thyroid lobe. Multifocality was significantly associated with recurrence in univariable and multivariable analyses (adjusted hazard ratio 3·16, 95 per cent c.i. 1·25 to 7·98; P = 0·015). Disease-free survival (DFS) varied according to multifocality (P = 0·010). The five risk staging systems were not associated with recurrence, and their Harrell's C-index ranged from 0·500 to 0·531. DFS rates did not differ between the risk categories in each system.

CONCLUSION

Although the recurrence rate after hemithyroidectomy in patients with low- and intermediate-risk PTC was low, meticulous follow-up focusing on the remaining thyroid lobe is needed for early detection and timely management of recurrence. The risk scoring systems in current use have no predictive role in these patients.

Predicting the factors associated with central lymph node metastasis in clinical node-negative (cN0) papillary thyroid microcarcinoma

PURPOSE

The aim of the present study was to investigate the risk factors associated with central lymph node metastasis (CLNM) in papillary thyroid microcarcinoma (PTMC).

METHODS

A total of 553 patients with PTMC confirmed by histological examination, who underwent thyroidectomy and central neck dissection (CND), were enrolled. The clinicopathological and ultrasonographic features from the patients were analyzed retrospectively.

RESULTS

PTMC patient age, Hashimoto thyroiditis (HT), tumor location, extrathyroidal extension (ETE), microcalcification and higher E values were correlated with the incidence of CLNM. Multivariate logistic regression analysis showed that age, HT, tumor location, ETE and E_max were related to the extent of CLNM. Chi-squared automatic interaction detection (CHAID) classification tree model showed that patients with tumor in upper/lower third combined ETE had a high risk of CLNM. Furthermore, cN0 PTMC patients with age ≤ 45 years and ETE had more extensive CLNM.

CONCLUSION

Our observations could be helpful for the assessment of prognostic factors of PTMC patients with CLNM.

Evaluation of surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm

Background

The objective of this study was to evaluate the surgical risk and prognosis between thyroid nodules of size <1 and ≥1 cm and to explore whether it is reasonable generally to ignore the diagnosis and treatment of thyroid nodules and thyroid carcinoma <1 cm in wide areas of China.

Methods

A retrospective observational study included all first-time thyroid surgery patients between January 2005 and December 2016 of the First Affiliated Hospital of Harbin Medical University. All patients were divided into two groups (group A: <1 cm, group B: ≥1 cm) according to the maximum diameter of the nodules and demographics, surgery procedure, pathology, postoperative complications, morbidity, and mortality were analyzed.

Results

A total of 6,317 patients were reviewed and 3,424 (54.20%) of them were malignant; 2,128 patients in group A and 4,189 in group B. Patients in group A had better pathological diagnosis, inferior extent of lymph node metastasis, less surgical complexity, fewer postoperative complications, and longer disease-free survival (DFS).

Conclusions

Thyroid operations were safer and involved fewer postoperative complications when thyroid nodules were <1 cm and patients who were diagnosed with malignant thyroid disease had superior prognoses. Underdeveloped regions of China should diagnose and treat thyroid nodules <1 cm early.

Multicentricity Is More Common in Thyroid Papillary Microcancer with a Preoperative Diagnosis Compared to Incidental Microcancer

OBJECTIVE

Although multicentricity is a common feature of thyroid papillary microcancer, it might be difficult to predict this histopathological feature preoperatively.

METHODS

The records of 306 papillary microcancer patients who underwent thyroidectomy were evaluated. Papillary microcancer was diagnosed as an incidental histopathological finding in 242 (group 1), and by preoperative fine-needle aspiration biopsy in 64 (group 2). Demographic data and histopathological features were compared between the two groups.

RESULTS

Age (44 ± 11.4 vs. 43 ± 14 years) and male/female ratio (44/193 vs. 12/52) showed no significant difference between groups 1 and 2 (p > 0.05). Mean tumor size was significantly larger in group 2 (5.2 ± 2.8 mm) compared to group 1 (3.7 ± 2.4 mm) (p = 0.004). The frequency of thyroid capsule invasion (44 vs. 19%, p = 0.0001), microscopic extrathyroidal invasion (25 vs. 10%, p = 0.004) and multicentricity (44 vs. 29%, p = 0.04), and bilateral lobar involvement (22 vs. 10%, p = 0.0001) was significantly higher in group 2 compared to group 1.

CONCLUSION

Multicentricity with bilateral lobar involvement and aggressive histopathological features are more frequent in papillary microcancer patients diagnosed with preoperative fine-needle aspiration biopsy compared to papillary microcancer diagnosed as postoperative incidental histopathological finding.

PROGNOSIS OF DIFFERENTIATED THYROID CARCINOMA IN PATIENTS WITH GRAVES DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

Objective: It is still controversial whether differentiated thyroid carcinoma (DTC) in patients with Graves disease (GD) can be more aggressive than non-Graves DTC. We conducted a systematic review and meta-analysis to examine the association between GD and prognosis in patients with DTC. Methods: We comprehensively searched the databases of MEDLINE and EMBASE from inception to March 2019. We included published studies that compared the risk of mortality and prognosis between DTC patients with GD and those with non-GD. Data from each study were combined using the random-effects model. Results: Twenty-five studies from February 1988 to May 2018 were included (987 DTC patients with GD and 2,064 non-Graves DTC patients). The DTC patients with GD had a significantly higher risk of associated multifocality/multicentricity (odds ratio, 1.45; 95% confidence interval, 1.04 to 2.02; I², 6.5%; P = .381) and distant metastasis at the time of cancer diagnosis (odds ratio, 2.19; 95% confidence interval, 1.08 to 4.47; I², 0.0%; P = .497), but this was not associated with DTC-related mortality and recurrence/persistence during follow-up. Conclusion: Our meta-analysis demonstrates a statistically significant increased risk of multifocality/multicentricity and distant metastasis at the time of cancer diagnosis in DTC patients with GD than those without GD. Abbreviations: CI = confidence interval; DTC = differentiated thyroid carcinoma; GD = Graves disease; LN = lymph node; OR = odds ratio; PTC = papillary thyroid carcinoma; TC = thyroid carcinoma; TSAb = thyroid-stimulating antibody; TSH = thyroid-stimulating hormone.

Incidental thyroid carcinomas. A retrospective study

AIM

The aim of the present study is to report our series of incidental thyroid carcinomas in the last 15 years and their follow-up, discussing therapeutics indications and surgical choices.

PATIENTS AND METHODS

We have considered 1793 patients operated on Surgical Sciences Department of "Sapienza" University of Rome from January 1, 2001 to December 31, 2015. The study was conducted on 83 totally thyroidectomized patients with a real incidental thyroid carcinoma, by clinical, laboratory and instrumental controls. Whole-body scan was the most important test in postoperative evaluation.

RESULTS

In our series, the incidence of incidental carcinomas was 4.62%. Compared to the total number of cancer patients, the percentage is 21,9%. In 15.66% of cases there was multifocality and in 7.23% also bilaterality. Regarding the histological type, in all cases they were papillary carcinoma. The size of the neoplastic lesions ranged from a minimum of 3 to a maximum of 10 mm. Whole-body scan revealed lymph node metastasis in 57.69% of patients.

DISCUSSION

Comparing these data with our previous studies we have seen a significant increase in incidence of incidental thyroid carcinomas over the years. Our therapeutical choice is total thyroidectomy and complection thyroidectomy after lobectomy, because of a relevant percentage of multifocality and/or bilaterality of these tumors. Many Authors on the contrary prefer a more conservative approach invoking the good prognosis of these tumors. The 57.69% of lymph node metastasis at postoperative whole-body scan comfort us in our setting.

CONCLUSION

Incidental thyroid carcinomas are not uncommon. We consider only tumors until 1 cm in diameter. Multifocality and bilaterality are often present such as occult lymph node metastasis. Our therapeutical choice is total thyroidectomy in order to conduct a proper follow-up.

Surgical Treatment in Papillary Thyroid Microcarcinoma

Despite the notable increasing incidence of papillary thyroid microcarcinoma (PTMC), the optimal treatment of the patients with PTMC remains controversial. Because of no consensus about its treatment, the suggested treatment varies from active surveillance alone to total thyroidectomy. Although the 2015 revised American Thyroid Association guideline recommends hemithyroidectomy as the first-line treatment, active surveillance has also been discussed and accepted as another approach for the patients with PTMC. However, the same guideline does not recommend fine needle aspiration biopsy for nodules sized <1 cm, even it is suspicious. In such situation, neither active surveillance nor hemithyroidectomy could be discussed, with a lack of objective cytologic data about the nodules sized <1 cm. In this situation, the decision to perform FNAB to the nodules <1 cm in size depends on the performer of the thyroid ultrasonography. In this invited review, we have discussed the diagnosis and prognostic factors for PTMCs. We have also discussed surgical strategies as the accepted the first-line treatment in patients with PTMC.

Thyroid surgery for differentiated thyroid cancer - recent advances and future directions

Population-based studies have demonstrated that an increasing number of incidental thyroid nodules are being identified. The corresponding increase in thyroid-based diagnostic procedures, such as fine-needle aspiration biopsy, has in part led to an increase in the diagnoses of thyroid cancers and to more thyroid surgeries being performed. Small papillary thyroid cancers account for most of this increase in diagnoses. These cancers are considered to be low risk because of the excellent patient outcomes, with a 5-year disease-specific survival of >98%. As a result, controversy remains regarding the optimal management of newly diagnosed differentiated thyroid cancer, as the complications related to thyroidectomy (primarily recurrent laryngeal nerve injury and hypoparathyroidism) have considerable effects on patient quality of life. This Review highlights current debates, including undertaking active surveillance versus thyroid surgery for papillary thyroid microcarcinoma, the extent of thyroid surgery and lymphadenectomy for low-risk differentiated thyroid cancer, and the use of molecular testing to guide decision-making about whether surgery is required and the extent of the initial operation. This Review includes a discussion of current consensus guideline recommendations regarding these topics in patients with differentiated thyroid cancer. Additionally, innovative thyroidectomy techniques (including robotic and transoral approaches) are discussed, with an emphasis on patient preferences around decision-making and outcomes following thyroidectomy.

The role of radioactive iodine therapy in papillary thyroid cancer: an observational study based on SEER

BACKGROUND

Papillary thyroid cancer (PTC) is a common endocrine malignancy with relatively good prognosis. Radioactive iodine (RAI) is considered effective for patients with total or nearly total thyroidectomy, but the beneficial effects of RAI are still controversial.

MATERIALS AND METHODS

To determine whether RAI therapy could improve the survival rates of PTC patients, we conducted a retrospective analysis using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program. Disease-specific survival (DSS) was obtained using multivariate Cox proportional hazard regressions.

RESULTS

DSS was improved by RAI ablation in patients with tumor >2 cm, age >45 years and gross extrathyroidal or lymph node metastasis. In a further analysis, RAI therapy did not improve the DSS in patients with tumor <2 cm except those with distant metastasis. For patients with tumor >2 cm, those involving gross extrathyroidal extension, age >45 years or disease in the lymph nodes, DSS was improved after RAI therapy. Patients with distant metastasis always benefited from RAI ablation.

CONCLUSION

RAI ablation should be recommended to patients with tumor <2 cm and distant metastasis or patients with tumor >2 cm and one of the following risk factors: gross extrathyroidal extension, age >45 years, lymph node and distant metastases.

SONOGRAPHIC FEATURES OF MULTIFOCAL PAPILLARY THYROID CARCINOMAS

OBJECTIVE

It is uncertain whether papillary thyroid carcinomas (PTCs) of the same subtype display similar sonographic features. This retrospective analysis of pre-operative sonographic and pathologic findings aimed to assess whether PTCs of the same subtype share sonographic features.

METHODS

Before undergoing thyroid surgery, 137 patients underwent ultrasound (US) examination. A single radiologist used a picture archiving and communication system and pathologic reports to investigate all sonographic features of the largest and second largest PTCs. Additionally, the radiologist evaluated the similarity of sonographic features between primary (largest), secondary (second largest), and daughter (secondary with same subtype as the primary) PTCs.

RESULTS

Of the 137 PTC patients, 48 (35.0%) had multiple PTCs; however, 5 had no US images of the secondary PTC. Of the 43 secondary PTCs with US images, 9 (20.9%) secondary PTCs were of a different subtype than the primary PTC and revealed sonographic features that differed from those of the primary PTC. Of the 48 patients with multiple PTCs, the subtype was the same in the primary and secondary PTCs in 34 (70.8%) patients. Of the 34 daughter PTCs, 32 (94.1%) had sonographic features similar to those of the primary PTC, whereas 2 (5.9%) showed different sonographic features than the primary PTC. There was no significant difference between primary and daughter PTCs in the size, location, sonographic features, or Korean Thyroid Imaging Reporting and Data System category ( P>.05).

CONCLUSION

Daughter PTCs show similar sonographic features as the primary PTC.

ABBREVIATIONS

K-TIRADS = Korean Thyroid Imaging Reporting and Data System; PTC = papillary thyroid carcinoma; US = ultrasound.

Radioactive Iodine Ablation Decrease Recurrences in Papillary Thyroid Microcarcinoma with Lateral Lymph Node Metastasis in Chinese Patients

Introduction

We aimed to carry out a retrospective study from a single institution to determine whether radioactive iodine (RAI) ablation decreases the risk of recurrence of papillary thyroid microcarcinoma (PTMC) patients that presented with lateral lymph node metastasis (LLNM).

Methods

We retrospectively analyzed a total of 6361 consecutive PTMC patients who initially underwent surgery for the treatment of thyroid carcinoma at the First Hospital of Jilin University, between January 2005 and February 2015. Altogether, 137 patients with PTMC with LLNM have been enrolled in our study.

Results

The disease-free survival period was significantly shorter for the RAI (−) patients than for the RAI (+) patients (p = 0.0074 by the log-rank test). The disease-free survival rates at 5 and 10 years were 93.02 and 87.5%, respectively, in the RAI (−) group and 100 and 96.81%, respectively, in the RAI (+) group. CLNM ratio and LLNM ratio were factors identified for multivariate analysis by Cox’s proportional hazards method yielding risk ratios of 7.281 [CI 1.804–17.554; p = 0.010] and 1.157 [CI 1.0125–9.381; p = 0.048] in the RAI (−) group.

Conclusion

Taken together, RAI may be beneficial for PTMC with LLNM, especially when CLNM ratio or LLNM ratio was greater than 0.5.

Risk factors associated with intrathyroid extension of thyroid microcarcinomas

PURPOSE

The aims of this study were to investigate the rate of intrathyroid extension of papillary thyroid microcarcinoma (PTMC) in patients operated for benign thyroid disease and to identify independent risk factors associated with it.

METHODS

A retrospective study of 301 patients operated for benign thyroid diseases (hyperthyroid diseases, multinodular goitre, Hashimoto thyroiditis and benign thyroid tumours) was performed at a high-volume endocrine surgery unit of a tertiary referral academic hospital, in a 5-year period. These patients had a PTMC incidentally discovered on definite histopathological findings following total or near-total thyroidectomy. Since distinguishing between intrathyroid extension of PTMC as the result of intrathyroid dissemination or as the result of multicentricity is challenging, we observed them together as multifocality. In statistical analysis, we used standard descriptive statistics and univariate and multivariate logistic regression analysis to determine independent risk factors associated with multifocality.

RESULTS

In our study, there were 85.4% females and 14.6% males with a median age of 54 years. A multinodular goitre (32.5%) was the most common indication for an operation. Most patients (68.4%) had a PTMC that was 5 mm or smaller. The most frequent histological variants of PTMC were the follicular variant (52.8%), followed by the papillary variant (22.6%) and the mixed follicular-papillary variant (18.6%). A multifocal PTMC was present in 26.6% of cases. An independent protective factor for multifocality of PTMC was a thyroid gland that weighed more than 38 g (OR 0.55, 95% CI 0.31-0.97, p = 0.039). Size of PTMC greater than 5 mm was an independent risk factor for a multifocal PTMC (OR 3.26, 95% CI 1.85-5.75, p = 0.000). Finally, the mixed follicular-papillary variant of PTMC represents an independent risk factor for a multifocal PTMC (OR 2.42, 95% CI 1.09-5.36, p = 0.030).

CONCLUSIONS

Intrathyroid extension is present in more than a quarter of PTMCs found in patients operated for benign thyroid disease. Independent risk factors for intrathyroid extension are size of PTMC greater than 5 mm and the mixed follicular-papillary variant of PTMC, while a large thyroid gland is an independent protective factor.

Too Much of a Good Thing: Radioactive Iodine Ablation Use for Micropapillary Thyroid Carcinoma

Radioactive iodine (RAI) is not routinely recommended for the adjuvant treatment of micro-papillary thyroid carcinoma (MPTC). We aimed to report on clinical and pathologic factors associated with the use of RAI in these patients. We queried the Surveillance, Epidemiology, and End Results database for patients who underwent surgery for MPTC (tumor size ≤1 cm) from 1988 to 2009. We excluded patients without a biopsy-proven diagnosis, those diagnosed at autopsy, and patients with documented extra-thyroidal extension. Multivariate logistic regression models predicted the use of RAI based on patient, tumor, and treatment-related factors. We identified 24,076 patients with MPTC that were eligible for study inclusion. Of these, 6,172 (25.6%) received RAI. Lymph node metastases were present in 23.8 per cent of those for whom lymph node status was known. On multivariate analysis, an increasing number of positive nodes, increasing tumor size, Asian race, and male gender predicted the use of RAI. RAI use was less likely in those with advancing age, an increasing number of lymph nodes examined and patients that received less than a total thyroidectomy. Among node-negative patients, Asian race and increasing tumor size predicted the use of RAI. Factors predicting decreased use of RAI were an increasing number of lymph nodes examined, unknown race, less than a total thyroidectomy, and advancing age. A significant number of MPTC patients receive potentially unnecessary RAI.

Risk factors stratifying malignancy of nodules in contralateral thyroid lobe in patients with pre-operative ultrasound indicated unilateral papillary thyroid carcinoma: A retrospective analysis from single centre

OBJECTIVE

Papillary thyroid carcinoma (PTC) is the most common thyroid carcinoma with a favourable clinical outcome. For unilateral PTC patients with thyroid nodules in the contralateral lobes, the necessity of total thyroidectomy (TT) is still in doubt. In this study, we aimed to define clinical factors that could be indicators for malignancy in nodules in the contralateral thyroid lobe, which could aid the clinician in selecting the appropriate operation approach.

DESIGN, PATIENTS AND MEASUREMENTS

This is a retrospective study from January 2014 to December 2016 conducted in Shanghai Ruijin Hospital. A total of 1442 cases with unilateral PTC and ultrasonographically benign nodules in the contralateral lobe who underwent TT at a single institution were enrolled. All patients underwent pre-operative ultrasonography (US), and all the cases were confirmed by board-certified pathologists. Clinicopathological features such as age, gender, tumour location, tumour size, TgAb and TPOAb levels, capsular invasion, multifocality, central lymph node metastases and BRAF mutation were examined to evaluate the rate of malignancy in the contralateral thyroid nodules.

RESULTS

In total, 47% of patients (677 cases)were confirmed to have malignancy in the contralateral lobe. Univariant analysis indicated that capsular invasion, Hashimoto's thyroiditis, multifocal loci, central lymph node metastases as well as BRAF mutation predicted a high incidence of occult contralateral carcinoma. Multivariant analysis showed capsular invasion, multifocal ipsilateral thyroid lobe, central lymph node metastases as well as BRAF mutation can serve as independent predictors for malignancy in the contralateral thyroid lobe.

CONCLUSIONS

Malignancy in the contralateral lobe was found in 47% of patients. This finding was associated with multifocal primary carcinomas involvement, capsular invasion, Hashimoto's thyroiditis history, central lymph node metastases and BRAF mutation, which should therefore be taken into consideration when planning therapeutic strategy for the patients.

Long-term outcomes of central neck dissection for cN0 papillary thyroid carcinoma

OBJECTIVE

The risk-benefit ratio of central neck dissection (CND) in patients affected by papillary thyroid carcinoma (PTC) without clinical or ultrasonographic (US) evidence of neck lymph node metastasis (cN0) is currently debated. The aim of this study was to evaluate long-term outcome of CND on locoregional recurrence, distant metastasis, survival, and postoperative complications in a large series of patients with cN0-PTC.

STUDY DESIGN

Observational retrospective controlled study.

METHODS

Clinical records of patients (n=610) surgically treated for cN0-PTC at the Otolaryngology Unit of the Arcispedale Santa Maria Nuova-IRCCS, Reggio Emilia, Italy, from January 1984 to December 2008, were retrospectively reviewed. Study population was divided into three groups according to surgical treatment: Group A, total thyroidectomy (n=205); Group B, total thyroidectomy and elective ipsilateral CND (n=281); Group C, total thyroidectomy and bilateral CND (n=124).

RESULTS

Of a total of 610 patients, 305 (50%) were classified as low-risk, 278 (45.57%) as intermediate-risk, and 27 (4.43%) as high-risk. Response to initial therapy was excellent in 567 patients (92.95%), acceptable in 21 (3.44%), and incomplete in 22 (3.61%), with no significant differences among groups. Locoregional recurrence was detected in 32 (5.2%) out of 610 patients. Distant metastasis was found in 15 patients (2.5%). Statistical analysis showed no significant differences in the rates of locoregional recurrence (p=0.890) or distant metastasis (p=0.538) among groups. Disease-specific mortality and overall survival did not significantly differ among groups (p=0.248 and 0.223, respectively). Rate of permanent hypoparathyroidism was significantly higher in Group C patients compared to those in Groups A and B.

CONCLUSION

CND does not confer any clear advantage in the treatment of low-risk patients, regardless of surgical procedure. Instead, bilateral CND may be effective in limiting disease relapse and/or progression in patients at higher prognostic risk. Our data indicate that elective CND does not confer any clear advantage in terms of locoregional recurrence and long-term survival, as demonstrated by outcomes of the study Groups, regardless of their different prognostic risk. Elective CND allows a more accurate pathologic staging of central neck lymph nodes, despite its increasing the risk of permanent hypoparathyroidism. Intraoperative pathologic staging is a valuable tool to assess the risk of controlateral lymph node metastasis in the central neck compartment and to limit more aggressive surgery only to cases, otherwise understaged, with lymph node metastasis.

Application of Thyroid Imaging Reporting and Data System in the Ultrasound Assessment of Thyroid Nodules According to Physician Experience

OBJECTIVE

The aim of this study was to investigate and compare the diagnostic performances of the Thyroid Imaging Reporting and Data System (TIRADS) in differentiating benign and malignant thyroid nodules according to the level of physician experience.

MATERIALS AND METHODS

From March to October 2013, 1102 patients with 1128 thyroid nodules who underwent initial ultrasound-guided fine needle aspiration were included in this study. Thyroid nodules were categorized according to TIRADS. Diagnostic performances of ultrasound were compared according to performer experience using the χ test or Fisher exact test.

RESULTS

Of 1128 thyroid nodules, 281 were malignant, and 847 were benign. The risk of malignancy of each TIRADS category by the experienced and less experienced physicians were as follows: category 3 (0.9% vs 0%), category 4a (3.5% vs 1.3%), category 4b (7.3% vs 12.1%), category 4c (67.5% vs 44.9%), and category 5 (97.7% vs 76.5%). Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 99.1%, 35.9%, 52.5%, 35.5%, and 99.1%, respectively, for experienced physicians and 100%, 20.9%, 37.6%, 35.2%, and 100%, respectively, for less experienced physicians. Specificity, accuracy, and positive predictive value were statistically higher for experienced physicians than those for less experienced physicians (P < 0.001, 0.001, and 0.004). There was a significant difference in areas under the curve between the 2 groups (P < 0.001).

CONCLUSIONS

In conclusion, the diagnostic performance of the stratification of malignancy risk according to TIRADS categories was comparable between the experienced and less experienced physician groups. The application of TIRADS is reproducible, and it was easy to predict the probability of thyroid malignancy in both the experienced and less experienced physician groups.

The Genetics of Papillary Microcarcinomas of the Thyroid: Diagnostic and Prognostic Implications

Papillary microcarcinoma of the thyroid (mPTC) is defined by the WHO as a papillary thy-roid cancer measuring 10mm or less in diameter and it is nowadays a topic of intense debate among the members of the medical community due to its apparent “epidemic” rise. Although these tumors follow almost always an indolent clinical course and carry an excellent prognosis, it is known that a small sub-set may display a potentially aggressive behavior. Nevertheless, we still lack an accurate way of predict-ing those which will cause significant disease. In an attempt to address this problem, a number of clini-co-pathologic features have been studied as poor prognostic markers in mPTC, and their association with known genetic alterations in thyroid cancer has been evaluated. Herein we review the present knowledge concerning mPTC’s genetic profile, namely the prevalence of BRAF (V600E), RAS and TERT promoter mutations and RET/PTC and PAX8-PPARG rearrangements and report the results of the evaluation in the putative prognostic value of these genetic alterations in mPTC.

Clinical and histopathological characteristics of patients with incidental and nonincidental thyroid cancer

INTRODUCTION

Thyroid nodules (TNs) are a common pathology. Their prevalence increases with age. Some of them are suspected of malignancy and qualified for surgery. Sometimes their malignant nature is detected incidentally after a surgical procedure. The aim of the study is to analyze clinical and histopathological characteristics of patients with incidental and nonincidental thyroid carcinoma (ITC vs. NITC).

MATERIAL AND METHODS

The case records of 3,241 patients with solitary and multiple TNs who were treated consecutively between 2008 and 2014 were analyzed retrospectively. After the final selection 235 (7.25%) patients were included in the study (202 females and 33 males, mean age: 52.9 +16.5 years). Seventy-five (31.91%) cases were incidentally diagnosed and 160 (68.09%) were diagnosed before surgery.

RESULTS

We did not observe any differences in age, gender or stage of disease at the time of diagnosis between the patients with ITC and NITC (p = 0.366, p = 0.850, p = 0.226 respectively). The occurrence of solitary nodules in patients with NITC was significantly higher compared to patients with ITC (p < 0.0001). There were no differences in histopathological types of thyroid cancer (TC). The logistic regression analysis showed that solitary TC was an independent predictor of NITC (p < 0.0001).

CONCLUSIONS

There are no differences in gender, age or histopathological type of cancer in patients with ITC and NITC. Papillary TC is the predominant type in both groups. Incidence of TC in a solitary nodule is significantly higher in NITC than ITC. Solitary type of TC is an independent predictor of NITC. The prevalence of ITC is associated with multifocal type of TC.

Is familial papillary thyroid microcarcinoma more aggressive than sporadic form?

Purpose

With the increasing incidence of papillary thyroid microcarcinoma (PTMC), familial papillary thyroid microcarcinoma (FPTMC) is now recognized more frequently. However, the biological behavior of FPTMC is poorly understood. The aim of this study was to investigate the prevalence of FPTMC and its biological aggressiveness.

Methods

Between March 2006 and July 2010, 2,414 patients underwent primary surgical therapy for PTMC and 149 (6.2%) were further classified as FPTMC. To determine the biological aggressiveness of FPTMC, we compared the clinicopathological features and prognosis between FPTMC and sporadic PTMC (SPTMC).

Results

The male-to-female ratio was higher in FPTMC than in sporadic papillary thyroid microcarcinoma (SPTMC: 1:4.5 vs. 1:7.2, P = 0.041). The central lymph node (LN) metastasis rate was significantly higher in FPTMC than in SPTMC (36.2% vs. 24.2%, P = 0.002). The local recurrence rate was also higher in FPTMC than in SPTMC (4.5% vs. 0.6%, P < 0.001). We identified familial occurrence in 6.2% of cases of PTMC. FPTMC is associated with a high rate of central LN metastasis and local recurrence.

Conclusion

These findings suggest that close follow-up can be beneficial in FPTMC patients to detect local recurrence.

Patients with Multifocal Macroscopic Papillary Thyroid Carcinoma Have a Low Risk of Recurrence at Early Follow-Up after Total Thyroidectomy and Radioactive Iodine Treatment

BACKGROUND

Multifocal thyroid cancer involvement is a common presentation in papillary thyroid cancer. The risk of recurrence of intrathyroidal multifocal papillary microcarcinoma (<1 cm) is documented to be low. However, the risk of recurrence of multifocal macroscopic thyroid cancer is not known. Prior studies have suggested that both the number of foci and the presence of nodal involvement at diagnosis are important predictors of recurrence in multifocal papillary thyroid carcinoma (PTC).

OBJECTIVES

In this retrospective review of 99 patients presenting with multifocal macroscopic PTC (with 2 tumor foci >1 cm) without gross extrathyroidal extension, we examined the clinical outcomes of patients in the first 2 years after the initial therapy and at the end of the follow-up period (median: 5 years).

RESULTS

Half of the patients presenting with multifocal macroscopic PTC had nodal involvement at diagnosis. Only 4 patients had a recurrence on long-term follow-up, all with classic or tall-cell variant PTC with bulky nodal involvement at diagnosis. The number of tumor foci did not influence the risk of recurrence in this cohort. The median time to recurrence in these 4 patients was 11 years, with all patients having a recurrence after 9 years of follow-up. None of patients developed distant metastasis or died from thyroid cancer.

CONCLUSIONS

Patients presenting with multifocal macroscopic papillary thyroid cancer without bulky nodal involvement or gross extrathyroidal extension have a low risk of thyroid cancer recurrence.

Should the Prevalence of Incidental Thyroid Cancer Determine the Extent of Surgery in Multinodular Goiter?

Background

The most appropriate surgical procedure for multinodular goiter (MNG) remains under debate. Incidental thyroid carcinoma (ITC) is often identified on histopathological examination after thyroidectomy performed for presumed benign MNG.

Aim of the study

The aim of the study was to determine the value of radical surgery for MNG patients considering the prevalence of ITC diagnosed postoperatively.

Materials and Methods

We conducted retrospective analysis of the medical records of 2,306 patients surgically treated for MNG between 2008 and 2013 at one center. None of the patients presented with any suspicion of malignancy, history of familial thyroid cancer, multiple endocrine neoplasia syndrome or previous head or neck radiation exposure.

Results

Among the 2,306 MNG patients, ITC was detected in 49 (2.12%) (44 women and 5 men, with average ages of 52.2 (21–79) and 55.6 (52–62), respectively). Papillary thyroid carcinoma was significantly more frequently observed than other types of ITC (p<0.00001). Among the MNG patients, 866 (37.5%) underwent total/near total surgery, 464 (20.1%) received subtotal thyroidectomy, and 701 (30.3%) received the Dunhill operation. The remaining 275 (11.9%) patients underwent a less radical procedure and were classified as "others." Among the 49 (100%) patients with ITC, 28 (57.1%) underwent radical surgery. Another 21 (42.9%) patients required completion surgery due to an insufficient primary surgical procedure. A total of 21 (2.42%) patients in the total/near total surgery group were diagnosed with ITC, as well as 16 (2.48%) in the subtotal thyroidectomy group and 12 (1.71%) in the Dunhill operation group; 21 (100%), 4 (25%) and 3 (25%) of these patients, respectively, underwent radical surgery; thus, 0 (0%), 12 (75%) and 9 (75%) required completion surgery. The prevalence rates of ITC were comparable between the radical and subtotal surgery groups (2.42% and 3.44%, respectively, p = 0.4046), and the prevalence was higher in the radical surgery group than in the Dunhill operation group (2.42% and 1.71%, respectively, p = 0.0873). A significant difference was observed between the group of patients who underwent total/near total surgery, among whom all of the patients with ITC (100%) received primary radical surgery, and the groups of patients who received the subtotal and Dunhill operations, among whom only 25% of the patients with ITC in each group received primary radical surgery (p<0.0001).

Conclusions

More radical procedures for MNG result in a lower risk of reoperation for ITC. The prevalence of ITC on postoperative histopathological examination should determine the extent of surgery in MNG patients. In the future, total/near total thyroidectomy should be considered for MNG patients due to the increased prevalence of ITC to avoid the necessity for reoperation.

Papillary thyroid microcarcinoma: time to shift from surgery to active surveillance?

The incidence of differentiated thyroid cancer is increasing greatly in high-income countries. Roughly 50% of this increase is attributable to the identification of intrathyroidal papillary thyroid microcarcinomas. Since mortality associated with these tumours remains low and stable, the increasing diagnosis has led to concerns about overdiagnosis and overtreatment. Management of papillary thyroid microcarcinomas should take into account the reported absence of mortality when diagnosed in the absence of lymph node metastases and distant metastases, as shown even in recent studies promoting active surveillance; a low recurrence rate of 1-5%; and the risk of permanent complications from surgery that cannot be decreased to less than 1-3%, even in high-volume tertiary care centres with experienced surgeons. On the basis of these data, active surveillance with curative intent, in which active treatment is delayed until the cancer shows signs of significant progression to avoid side-effects of treatment, should be considered in properly selected patients.

Reappraisal of the indication for radioiodine thyroid ablation in differentiated thyroid cancer patients

Radioactive iodine therapy is administered to patients with differentiated thyroid cancer (DTC) for eradication of thyroid remnant after total thyroidectomy or, in patients with metastatic disease, for curative or palliative treatment. In past years, thyroid remnant ablation was indicated in almost every patient with a diagnosis of DTC. Nowadays, careful revision of patients' outcome has introduced the concept of risk-based selection of patients candidate to thyroid remnant ablation. The present review aims to underline the indications for thyroid remnant ablation and to address methodologies to be employed.

Partial Thyroidectomy for Papillary Thyroid Microcarcinoma: Is Completion Total Thyroidectomy Indicated?

BACKGROUND

Total thyroidectomy is a well-established surgical approach for the management of papillary thyroid cancer (PTC). However, the best surgical approach for papillary microcarcinoma is nowadays still debated. Both total thyroidectomy and simple lobectomy are used. We report the experience of a single University center in the treatment of thyroid microcarcinoma.

METHODS

A retrospective analysis on all patients who underwent thyroid surgery at our institution over a 24-year period (1991-2015) was performed. Patients were grouped according to whether they received total thyroidectomy (Group 1) or lobectomy (Group 2). Follow-up was made by routine clinical and ultrasound examination. Specific outcomes such as recurrence and need for reoperation as well as complications (transient vocal cord paralysis and hypocalcemia) were analyzed.

RESULTS

During the study period 880 patients underwent surgery for PTC. Group 1 and 2 consisted, respectively, of 756 and 124 patients. A micro PTC (<10 mm) was present in 251 and 69 specimen of Group 1 and 2. No evidence of disease recurrence in the follow-up was reported in patients with microPTC in Group 1 and in 57 patients of Group 2. In the remaining 12 patients completion thyroidectomy was carried out due to ultrasound findings of contralateral nodules (10), lymphadenopathy (1), and capsular invasion (1). Five of these patients had a contralateral papillary carcinoma on final histopathologic examination. Thus recurrence rate for patients of Group 2 was 7.3%. Morbidity rates were, respectively, for Group 1 and 2: transient nerve palsy 81 and 5 (11 vs. 7.3%, p = ns), transient hypoparathyroidism (Calcium <2.00 mmol/L) 137 (18.6%) and 0 (p < 0.0001). Three of the 12 patients of Group 2 undergoing further surgery had a transient hypoparathyroidism.

CONCLUSIONS

Thyroid lobectomy is an effective surgical strategy to manage papillary microcarcinomas with low complications. Routine completion thyroidectomy is not mandatory. Appropriate selection excluding high-risk patients is of paramount importance in order to achieve the best results.

Current Guidelines for Postoperative Treatment and Follow-Up of Well-Differentiated Thyroid Cancer

Well-differentiated thyroid cancer is increasing in incidence but the disease-specific mortality remains very low. The only effective adjuvant treatment is radioactive iodine ablation. Guidelines regarding the use and dosage of radioactive iodine depend on pathologic features of the primary and metastatic tumor that define risk. Long-term treatment includes thyroid-stimulating hormone suppression and surveillance with serum thyroglobulin and radiologic assessment for nodal recurrence.

Detection of Tumor Multifocality Is Important for Prediction of Tumor Recurrence in Papillary Thyroid Microcarcinoma: A Retrospective Study and Meta-Analysis

Background:

The clinicopathological characteristics and conclusive treatment modality for multifocal papillary thyroid microcarcinoma (mPTMC) have not been fully established.

Methods:

A retrospective study, systematic review, and meta-analysis were conducted to elucidate the clinicopathological significance of mPTMC. We investigated the multiplicity of 383 classical papillary thyroid microcarcinomas (PTMCs) and the clinicopathological significance of incidental mPTMCs. Correlation between tumor recurrence and multifocality in PTMCs was evaluated through a systematic review and meta-analysis.

Results:

Tumor multifocality was identified in 103 of 383 PTMCs (26.9%). On linear regression analysis, primary tumor diameter was significantly correlated with tumor number (R²=0.014, p=.021) and supplemental tumor diameter (R²=0.117, p=.023). Of 103 mPTMCs, 61 (59.2%) were non-incidental, with tumor detected on preoperative ultrasonography, and 42 (40.8%) were diagnosed (incidental mPTMCs) on pathological examination. Lymph node metastasis and higher tumor stage were significantly correlated with tumor multifocality. However, there was no difference in nodal metastasis or tumor stage between incidental and non-incidental mPTMCs. On meta-analysis, tumor multifocality was significantly correlated with tumor recurrence in PTMCs (odds ratio, 2.002; 95% confidence interval, 1.475 to 2.719, p<.001).

Conclusions:

Our results show that tumor multifocality in PTMC, regardless of manner of detection, is significantly correlated with aggressive tumor behavior.

'Incidental' and 'non-incidental' thyroid papillary microcarcinomas are two different entities

OBJECTIVE

Papillary thyroid microcarcinomas (microPTC) may be 'incidental' (Inc-microPTC), occasionally found at histology after surgery for benign disease or 'non-incidental' (Non-Inc-microPTC), diagnosed on clinical grounds. It is unclear whether these different microPTC reflect the same disease. The aim of the study was to compare Inc-microPTC and Non-Inc-microPTC for clinical and histological features as well as for serum TSH, a known factor involved in PTC development.

DESIGN

We evaluated histology and serum TSH levels of consecutive patients submitted to thyroidectomy for goiter with compressive symptoms or for cytological diagnosis suspicious/indicative of PTC.

METHODS

In total, 665 consecutive patients (259 with a single thyroid nodule, SN and 406 with a multinodular gland, MN) were included in the study. According to histology, patients were classified as: benign nodular goiter (Benign, n=291); Inc-microPTC (n=92); Non-Inc-microPTC (n=67) and PTC≥1cm (macroPTC, n=215).

RESULTS

Inc-microPTC were significantly more frequent in MN than in SN (66/406, 16.2% vs 26/259, 10.0%, P=0.02). Patients with Inc-microPTC compared with Non-Inc-microPTC were older (mean age±s.d. 53.3±13.2 years vs 44.9±14.8 years, P=0.0002), had a smaller tumor size (median 4mm vs 9mm, P<0.0001), a higher frequency of multifocality (70/92, 76.1% vs 35/67, 52.2% P=0.001) and lower levels of TSH (median 0.6mIU/L, IR: 0.4-1.0mIU/L vs value 1. mIU/L, IR: 0.6-1.4mIU/L vs P=0.0001).

CONCLUSION

Incidental and non-incidental papillary thyroid microcarcinomas appear to be two different entities.

No considerable changes in papillary thyroid microcarcinoma characteristics over a 30-year time period

Background

The prevalence of papillary thyroid microcarcinoma (PTMC) is continuously increasing but its clinical significance and management is still debatable. The aim of this study was to investigate possible changes in the clinical presentation, tumor characteristics, treatment modalities and long-term outcome during the last three decades in patients with PTMC.

Methods

We studied 335 patients with PTMC who were followed up for at least 5 years, from 1982 to 2015, and treated in accordance with the current literature or guidelines at each time-period. Patients were classified according to year of diagnosis into two time periods, TP1 from 1982–2000 and TP2 from 2001–2010.

Results

The mean follow-up of the whole cohort was 10.6 ± 5.3 (median 9) years. No change was noted in the mean age at diagnosis or the female to male ratio during the two time periods. In regard to tumor characteristics, multifocality and non-encapsulated follicular variant of PTMC was more often present while classic PTMC was less common in patients in the TP2, compared to patients in the TP1 (p = 0.007, p < 0.001 and p = 0.043 respectively). The prevalence of incidental PTMC was high but similar in both time periods (84.6 vs 80 %, p = 0.286). The majority of patients in TP2 underwent a total or near total thyroidectomy compared to patients in TP1 (91.7 vs 80 %, p = 0.001). However, more patients underwent thyroidectomy for toxic multinodular disease and less for Graves’ disease during TP1 compared to patients in the TP2 (p = 0.02 and 0.043 respectively). A significant percentage of patients underwent adjuvant radioiodine ablation, yet no difference was found between the two time periods (73.8 vs 79.5 %, p = 0.228). The rate of persistence was very low and not significant (3.1 vs 6.6 %, p = 0.165), while disease recurrence was observed in only 2 (0.6 %) patients, one from each time period.

Conclusions

We did not observe any important changes regarding the clinical presentation or tumor characteristics of PTMCs during a 30-year period. With applied interventions a favorable course was confirmed in the majority of patients without differences in recurrence or persistence during the last three decades.

Clonality analysis of multifocal papillary thyroid carcinoma by using genetic profiles

Papillary thyroid carcinoma (PTC) is the most common adult thyroid malignancy and often presents with multiple anatomically distinct foci within the thyroid, known as multifocal papillary thyroid carcinoma (MPTC). The widespread application of the next-generation sequencing technologies in cancer genomics research provides novel insights into determining the clonal relationship between multiple tumours within the same thyroid gland. For eight MPTC patients, we performed whole-exome sequencing and targeted region sequencing to identify the non-synonymous point mutations and gene rearrangements of distinct and spatially separated tumour foci. Among these eight MPTCs, completely discordant mutational spectra were observed in the distinct cancerous nodules of patients MPTC1 and 5, suggesting that these nodules originated from independent precursors. In another three cases (MPTC2, 6, and 8), the distinct MPTC foci of these patients had no other shared mutations except BRAF V600E, also indicating likely independent origins. Two patients (MPTC3 and 4) shared almost identical mutational spectra amongst their separate tumour nodules, suggesting a common clonal origin. MPTC patient 7 had seven cancer foci, of which two foci shared 66.7% of mutations, while the remaining cancer foci displayed no common non-synonymous mutations, indicating that MPTC7 has multiple independent origins accompanied by intraglandular disease dissemination. In this study, we found that 75% of MPTC cases arose as independent tumours, which supports the field cancerization hypothesis describing multiple malignant lesions. MPTC may also arise from intrathyroidal metastases from a single malignant clone, as well as multiple independent origins accompanied by intrathyroidal metastasis.

Comparison of Antithyroglobulin Antibody Concentrations Before and After Ablation with 131I as a Predictor of Structural Disease in Differentiated Thyroid Carcinoma Patients with Undetectable Basal Thyroglobulin and Negative Neck Ultrasonography

BACKGROUND

Patients with differentiated thyroid carcinoma are submitted to a first assessment several months after initial therapy to evaluate their response to treatment. At that assessment, measurement of basal thyroglobulin (Tg) and antithyroglobulin antibodies (TgAb) and neck ultrasonography (US) are recommended. Serum Tg may be falsely negative in the presence of TgAb, and the management of patients with negative Tg but positive TgAb represents a challenge. The objective of this study was to correlate the variation in TgAb concentrations (comparison before and after ablation with (131)I) with the risk of structural disease.

METHODS

The sample consisted of 116 low- or intermediate-risk patients who had undetectable Tg, negative US at initial assessment, and positive TgAb 8-12 months after thyroidectomy and ablation with (131)I.

RESULTS

Comparison of TgAb concentrations before and after ablation with (131)I showed a reduction of >50% in 56 patients (group A), a reduction of <50% in 35 patients (group B), and an increase in 25 patients (group C). Metastases were detected in 5/116 (4.3%) patients during initial assessment (lymph nodes in two, pulmonary in two, and bone in one). They were diagnosed in 0/56, 2/35 (5.7%), and 3/25 (12%) patients of groups A, B, and C, respectively. During follow-up, metastases were detected in 7/111 (6.3%) patients (lymph nodes in six, and pulmonary in one). They occurred in 1/56 (1.8%), 3/33 (9%), and 3/22 (13.6%) patients of groups A, B, and C, respectively. Thus, structural disease was found in 1.8%, 14.3%, and 24% of groups A, B, and C, respectively. This rate was 4% in low-risk patients and 15.4% in intermediate-risk patients.

CONCLUSIONS

Among patients with undetectable Tg, negative US, and positive TgAb after ablation with (131)I, the frequency of structural disease was <5% in patients, with >50% reduction in TgAb. Among patients without a significant reduction in TgAb, approximately 10% of low-risk patients and >20% of intermediate-risk patients had structural disease. These results help define the indication for imaging methods other than US during initial assessment and long-term follow-up.

2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Task Force on Thyroid Nodules and Differentiated Thyroid Cancer

BACKGROUND

Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer.

METHODS

The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Grading System was used for critical appraisal of evidence and grading strength of recommendations for therapeutic interventions. We developed a similarly formatted system to appraise the quality of such studies and resultant recommendations. The guideline panel had complete editorial independence from the ATA. Competing interests of guideline task force members were regularly updated, managed, and communicated to the ATA and task force members.

RESULTS

The revised guidelines for the management of thyroid nodules include recommendations regarding initial evaluation, clinical and ultrasound criteria for fine-needle aspiration biopsy, interpretation of fine-needle aspiration biopsy results, use of molecular markers, and management of benign thyroid nodules. Recommendations regarding the initial management of thyroid cancer include those relating to screening for thyroid cancer, staging and risk assessment, surgical management, radioiodine remnant ablation and therapy, and thyrotropin suppression therapy using levothyroxine. Recommendations related to long-term management of differentiated thyroid cancer include those related to surveillance for recurrent disease using imaging and serum thyroglobulin, thyroid hormone therapy, management of recurrent and metastatic disease, consideration for clinical trials and targeted therapy, as well as directions for future research.

CONCLUSIONS

We have developed evidence-based recommendations to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer. They represent, in our opinion, contemporary optimal care for patients with these disorders.

Follicular cell-derived thyroid cancer

Follicular cell-derived thyroid cancers are derived from the follicular cells in the thyroid gland, which secrete the iodine-containing thyroid hormones. Follicular cell-derived thyroid cancers can be classified into papillary thyroid cancer (80-85%), follicular thyroid cancer (10-15%), poorly differentiated thyroid cancer (<2%) and undifferentiated (anaplastic) thyroid cancer (<2%), and these have an excellent prognosis with the exception of undifferentiated thyroid cancer. The advent and expansion of advanced diagnostic techniques has driven and continues to drive the epidemic of occult papillary thyroid cancer, owing to overdiagnosis of clinically irrelevant nodules. This transformation of the thyroid cancer landscape at molecular and clinical levels calls for the modification of management strategies towards personalized medicine based on individual risk assessment to deliver the most effective but least aggressive treatment. In thyroid cancer surgery, for instance, injuries to structures outside the thyroid gland, such as the recurrent laryngeal nerve in 2-5% of surgeries or the parathyroid glands in 5-10% of surgeries, negatively affect quality of life more than loss of the expendable thyroid gland. Furthermore, the risks associated with radioiodine ablation may outweigh the risks of persistent or recurrent disease and disease-specific mortality. Improvement in the health-related quality of life of survivors of follicular cell-derived thyroid cancer, which is decreased despite the generally favourable outcome, hinges on early tumour detection and minimization of treatment-related sequelae. Future opportunities include more widespread adoption of molecular and clinical risk stratification and identification of actionable targets for individualized therapies.

Radioiodine Remnant Ablation: A Critical Review

Radioiodine remnant ablation (RRA) is considered a safe and effective method for eliminating residual thyroid tissue, as well as microscopic disease if at all present in thyroid bed following thyroidectomy. The rationale of RRA is that in the absence of thyroid tissue, serum thyroglobulin (Tg) measurement can be used as an excellent tumor marker. Other considerations are like the presence of significant remnant thyroid tissue makes detection and treatment of nodal or distant metastases difficult. Rarely, microscopic disease in the thyroid bed if not ablated, in the future, could be a source of anaplastic transformation. On the other hand, microscopic tumor emboli in distant sites could be the cause of distant metastasis too. The ablation of remnant tissue would in all probability eliminate these theoretical risks. It may be noted that all these are unproven contentious issues except postablation serum Tg estimation that could be a good tumor marker for detecting early biochemical recurrence in long-term follow-up strategy. Radioactive iodine is administered as a form of “adjuvant therapy” for remnant ablation. There have been several reports with regard to the administered dose for remnant ablation. The first report of a prospective randomized clinical trial was published from India by a prospective randomized study conducted at the All India Institute of Medical Sciences, New Delhi in the year 1996. The study reported that increasing the empirical ¹³¹I initial dose to more than 50 mCi results in plateauing of the dose-response curve and thus, conventional high-dose remnant ablation needs critical evaluation. Recently, two important studies were published: One from French group and the other from UK on a similar line. Interestingly, all three studies conducted in three different geographical regions of the world showed exactly similar conclusion. The new era of low-dose remnant ablation has taken a firm scientific footing across the continents.

Lack of Associations between Body Mass Index and Clinical Outcomes in Patients with Papillary Thyroid Carcinoma

BACKGROUND

Obesity is associated with aggressive pathological features and poor clinical outcomes in breast and prostate cancers. In papillary thyroid carcinoma (PTC), these relationships remain still controversial. This study aimed to evaluate the associations between body mass index (BMI) and the clinical outcomes of patients with PTC.

METHODS

This retrospective study included 1,189 patients who underwent total thyroidectomy for PTCs equal to or larger than 1 cm in size. Clinical outcomes were evaluated and compared based on the BMI quartiles.

RESULTS

There were no significant associations between BMI quartiles and primary tumor size, extrathyroidal invasion, cervical lymph node metastasis, or distant metastasis. However, an increase in mean age was associated with an increased BMI (P for trend <0.001). Multifocality and advanced tumor-node-metastasis (TNM) stage (stage III or IV) were significantly associated with increases of BMI (P for trend 0.02 and <0.001, respectively). However, these associations of multifocality and advanced TNM stage with BMI were not significant in multivariate analyses adjusted for age and gender. Moreover, there were no differences in recurrence-free survivals according to BMI quartiles (P=0.26).

CONCLUSION

In the present study, BMI was not associated with the aggressive clinicopathological features or recurrence-free survivals in patients with PTC.