Papillary thyroid microcarcinoma: how to diagnose and manage this epidemic?

Efficacy of ultrasound-guided radiofrequency ablation of papillary thyroid microcarcinoma after one year

OBJECTIVE

This study aims to evaluate the feasibility and safety of percutaneous radiofrequency ablation guided by ultrasound for treating papillary thyroid microcarcinoma.

METHOD

At our institution, fifty people who had been treated for micropapillary thyroid cancer with ultrasound-guided radiofrequency ablation were chosen. Thyroid function was evaluated after one month, and the volume of the ablation region was assessed immediately, 3, 6, and 12 months after treatment. At the same time, the complications or adverse reactions after treatment were evaluated.

RESULTS

As time passed, the volume of the ablation area decreased gradually, showing a regression trend. There was a significant difference in the volume of the ablation area between adjacent groups (P < 0.05), and the tumor volume reduction ratio (VRR) of the ablation area was a statistically significant difference between adjacent groups (P < 0.05). There was no significant difference between the indexes related to thyroid function before and after treatment(P > 0.05). No local recurrence or distant metastasis was found during follow-up; The most common complication after the operation was a slight pain in the neck. A few patients had toothache and neck swelling symptoms, and the above symptoms subsided within 24 h after the operation.

CONCLUSION

Ultrasound-guided radiofrequency ablation is safe and effective for treating single-focus micropapillary thyroid carcinoma while retaining thyroid function, with few and minor complications, which can be used as an ideal surgical option.

Association between chronic lymphocityc thyroiditis and papillary thyroid carcinoma: Systematic review and meta-analysis of studies on surgical specimens

Introduction. Inconsistent results exist in the literature regarding the hypothesis statement suggesting an increased likelihood of documenting papillary thyroid carcinoma (PTC) in surgical specimens with changes compatible with chronic lymphocytic thyroiditis. Existing meta-analyses have included studies that are not methodologically comparable and do not propose clear sources of bias, thus, this is justification for the present meta-analysis. Methods. A literature search in PubMed and Embase was performed from January 1, 1950 to December 31, 2020. Retrospective studies comparing the prevalence of papillary thyroid carcinoma in specimens with and without chronic lymphocytic thyroiditis changes were obtained. The collected evidence was statistically analyzed. Results. A total of 22 articles were included. The study population consisted of 63,548 surgical specimens. The pooled OR, based on the studies, was 1.81 (95% CI: 1.51-2.21). There was heterogeneity between the distribution of prevalence ratios and opportunity ratios across studies (I²= 91%; p>0.00001). The funnel plot shape of the studies included in the analysis appears to be symmetrical, indicating the absence of bias attributable to small studies. Conclusions. The current literature suggests that there is an increased risk of documenting papillary thyroid carcinoma in surgical specimens in which chronic lymphocytic thyroiditis-compatible changes are observed; however, there are sources of bias that will not be possible to control for in retrospective studies, so we recommend studying the hypothesis suggesting an increased likelihood of diagnosing PTC in specimens with chronic lymphocytic thyroiditis-compatible changes using prospective methodologies.

A 5-year follow-up study on the efficacy and safety of ultrasound-guided laser ablation in elderly patients with papillary thyroid microcarcinoma: A retrospective, single-center study from China

OBJECTIVE

The aim of this study is to evaluate the long-term efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for the treatment of elderly patients with papillary thyroid microcarcinoma (PTMC).

METHODS

From September 2015 to April 2017, 38 elderly patients with PTMC confirmed through fine-needle aspiration biopsy (FNAB) were treated with PLA. Before the treatment, the location and volume of the nodule together with the patients' symptoms were evaluated. Twenty-four hours after the treatment, contrast-enhanced ultrasound (CEUS) was performed to evaluate the completeness of the ablation. To evaluate the volume of the ablation area and recurrence or metastasis, ultrasound examination was performed at 1, 3, 6, and 12 months after the treatment and every 6 months thereafter. FNAB was performed for any suspicious recurrence or metastasis lesions.

RESULT

The ablation of all the 38 patients was all achieved completely as confirmed by CEUS. No obvious complications were found. The success rate of single ablation was 100%. The average follow-up time was 64.58 ± 5.29 months (60-78 months). By the time of the last follow-up, 31 (81.58%) ablation lesions disappeared completely and seven (18.42%) ablation lesions showed scar-like changes. The volume of nodules was 40.69 ± 16.45 mm³ before operation, which decreased to 0.22 ± 0.76 mm³ by the end of 42 months, and all nodules disappeared 4 years after ablation (P < 0.01). At 6, 12, 18, 24, 30, 36, and 42 months after ablation, the average volume reduction rates (VRRs) were 12.09%, 31.21%, 50.9%, 72.06%, 84.79%, 95.65%, and 100%, respectively. Of all the patients enrolled, one patient (2.6%) had local recurrence and was treated with PLA again. No regrowth of treated nodule or lymph node metastasis and distant metastases was detected.

CONCLUSION

Ultrasound-guided PLA is effective and safe for the treatment of elderly patients with PTMC who are ineligible for surgery.

Influence of lesion size on shear wave elastography in the diagnosis of benign and malignant thyroid nodules

In shear wave elastography (SWE) studies, the optimal cutoff value of Young's modulus for the diagnosis of benign and malignant thyroid nodules varies greatly, which affects the clinical application of the method. The objective of this study was to evaluate the influence of thyroid nodule size on the clinical diagnostic efficacy of SWE. A total of 356 thyroid nodules of 280 patients were divided into three groups according to size (Group A: ≤ 1 cm; Group B: 1-2 cm; Group C: ≥ 2 cm). SWE was used to measure the maximum Young's modulus (Emax) values of all thyroid nodules. Receiver operating characteristic (ROC) curves were drawn with pathological results as the gold standard. For all nodules, the optimal cutoff value of Emax in SWE for diagnosing malignant thyroid nodules was 36.2 kPa. The sensitivity and specificity were 76.5% and 78.4%, respectively. Groups A, B, and C had different optimal Emax cutoff values of 33.7 kPa, 37.7 kPa, and 55.1 kPa, respectively. The area under the ROC curve (AUC) values of Groups A, B, and C (0.844, 0.886, and 0.935, respectively) were all greater than the values for all lesions (0.830). The specificity values of Groups A, B, and C (86.4%, 82.6%, and 88.2%, respectively) were all increased, and the sensitivity values of Groups B and C (89.7% and 96.4%, respectively) were also increased compared with the values for all lesions. Thyroid nodule size affects the optimal Emax cutoff value of SWE. We suggest that different cutoff values be used to diagnose benign and malignant thyroid nodules according to lesion size.

Long-Term Efficacy of Ultrasound-Guided Percutaneous Laser Ablation for Low-Risk Papillary Thyroid Microcarcinoma: A 5-Year Follow-Up Study

Objective

To evaluate the long-term efficacy and safety of ultrasound-guided percutaneous laser ablation (PLA) for the treatment of low-risk papillary thyroid microcarcinoma (PTMC).

Methods

From June 2012 to May 2015, 105 patients with solitary, pathologically confirmed PTMC lesions were treated with ultrasound-guided PLA. Nodule location, nodule volume, thyroid function, and clinical symptoms were evaluated before ablation. Contrast-enhanced ultrasound (CEUS) was performed 1 h after treatment to evaluate whether the ablation was complete. Ultrasound examination was performed at 1, 3, 6, and 12 months after ablation and every 6 months thereafter to determine the size of the ablation area and search for recurrence in the thyroid parenchyma and lymph node metastasis. Thyroid function was examined before and 1 month after ablation. Fine needle aspiration biopsy was performed for any suspicious metastatic lymph nodes and recurrent lesions in the thyroid.

Results

All 105 lesions were completely inactivated after one ablation, making the success rate for single ablation 100%. The average ablation time was 2.78 ± 1.05 min, and the average ablation energy was 505 ± 185 J. All patients could tolerate and complete the ablation. No serious complications occurred during the treatment; only minor side effects such as pain and local discomfort were reported. The volume reduction rates were −781.14 ± 653.29% at 1 h posttreatment and −268.65 ± 179.57%, −98.39 ± 76.58%, 36.78 ± 30.32%, 75.55 ± 21.81%, 96.79 ± 10.57%, and 100% at 1, 3, 6, 12, 18, and 24 months after ablation, respectively. This rate remained 100% at the later follow-up times. Overall, 28 (26.67%), 74 (70.48%), 96 (91.43%), and 103 (100%) were completely absorbed by 6, 12, 18, and 24 months after PLA. One patient developed another lesion 12 months after ablation, and two patients had central cervical lymph node metastasis 24 months after ablation.

Conclusion

PLA is a safe and effective alternative clinical treatment for low-risk PTMC.

Peripheral Versus Intraparenchymal Papillary Thyroid Microcarcinoma: Different Morphologies and PD-L1 Expression

Peripheral localisation of papillary thyroid microcarcinoma (PTMC), in comparison with intraparenchymal PTMC (i-PTMC) is related to some clinicopathological features related with biological aggressiveness, including lymph node metastasis (LNM). The expression of PD-L1 in tumour cell has been associated with increased tumour survival, progression, and potentially an aggressive clinical course. This study evaluates the relation between clinicopathological features of PTMC, including tumour localisation, with PD-L1 immunoexpression. The study included 99 patients with the histological diagnosis of PTMC (≥ 5 mm). PD-L1 protein expression was assessed by immunohistochemistry. PTMCs were divided into the four following groups: G1- peripherally localised PTMC (p-PTMC) with PD-L1 expression; G2-p-PTMC without PD-L1 expression; G3-i-PTMC with PD-L1 expression and G4-i-PTMC without PD-L1 expression. G1 was the most frequent (n = 46; 46.5%), followed by G4 (n = 25; 25.3%) and similar distribution of G3 (n = 15; 15.2%) and G2 (n = 13; 13.1%). In comparison with other groups, G1 was significantly associated with classical morphology, invasive growth, lymphatic invasion (LI), vascular invasion (VI), psammoma bodies, intratumoral fibrosis, PD-L1 positive tumour-infiltrating lymphocytes, and multinuclear giant cells (MGCs). G4 more commonly exhibited follicular morphology, expansive/circumscribed growth, and absence of the following: intratumoural fibrosis, LI, VI, psammoma bodies, PD-L1 positive tumour-infiltrating lymphocytes, and MGCs. LNMs were significantly more frequent in G1 in comparison with the other groups (p = 0.000). In conclusion, morphology and tumour microenvironment of p-PTMC with PD-L1 expression is different from i-PTMC without PD-L1 expression. The differences between these two groups of PTMC include clinicopathological features related with biological aggressiveness such as the occurrence of LNM.

Molecular Pathology of Non-familial Follicular Epithelial-Derived Thyroid Cancer in Adults: From RAS/BRAF-like Tumor Designations to Molecular Risk Stratification

This review addresses the impact of molecular alterations on the diagnosis and prognosis of differentiated thyroid carcinoma (DTC), including papillary, follicular, and well-differentiated carcinoma NOS, as well as oncocytic neoplasms. The molecular characterization of DTC is based upon the well-established dichotomy of BRAF-like and RAS-like designations, together with a remaining third group, less homogeneous, composed of non-BRAF-/non-RAS-like tumors. The role of BRAF V600E mutation in risk stratification is discussed in the clinico-pathological context, namely, staging and invasive features of classic papillary thyroid carcinoma (PTC) and histopathological variants carrying an excellent prognosis (microPTC) or a guarded prognosis, including the aggressive variants tall cell and hobnail cell PTCs. In follicular patterned tumors, namely, follicular thyroid carcinoma (FTC), with or without oncocytic features, the most prevalent molecular alteration are RAS mutations that do not carry prognostic significance. The only genetic alteration that has been proven to play a role in risk stratification of PTC and FTC is TERT promoter (TERTp) mutation.

Supraclavicular Approach of Lobectomy Improves Quality of Life for Patients With Unilateral Papillary Thyroid Microcarcinoma: A Prospective Cohort Study

OBJECTIVE

Postoperative neck symptoms, including pain, swelling, uncomfortable feelings during swallowing, and incision adhesion formation, are common in patients after lobectomy through the traditional middle neck approach. A new unilateral supraclavicular approach is proposed to protect the anterior cervical region and reduce related complications. The aim of this study is to investigate the efficacy, safety, and advantages of the supraclavicular approach in lobectomy for unilateral papillary thyroid microcarcinoma (PTMC).

METHODS

Two hundred sixty-three patients were recruited into either a conventional middle group (CM) or a new supraclavicular (NS) group. Clinicopathological features, surgically related variables, and postoperative symptoms were recorded. Quality of life (QOL) of all patients was assessed by the 12-item short-form health survey (SF-12) and thyroid cancer-specific QOL (THYCA-QoL) questionnaire in 3 and 12 months.

RESULTS

There were no statistically significant differences in clinicopathological features (including sex, age, multifocality, extrathyroidal extension, histological variants, largest tumor diameter, Hashimoto's thyroiditis, metastasized central lymph node, removed central lymph node, surgeon, BRAF mutation, and follow-up duration), hospitalization (including hospital cost, surgery time, and blood loss during surgery), and complications between the two groups. Patients who underwent lobectomy through the NS approach had significantly better SF-12 physical, mental, and THYCA-QoL than the CM group patients in both 3 and 12 months (all p < 0.001). Moreover, the NS group had a shorter hospitalization time.

CONCLUSION

In conclusion, the NS approach for lobectomy is a safe and effective method for reducing postoperative symptoms and increasing QOL in patients with unilateral PTMC in both 3 and 12 months' follow-up.

Clinicopathological Features as Prognostic Predictors of Poor Outcome in Papillary Thyroid Carcinoma

Simple Summary

Thyroid cancer incidence is increasing, with overdiagnosis being the major driver of the thyroid cancer “epidemic”. Papillary thyroid carcinoma, usually with excellent prognosis, sometimes has an aggressive metastatic pattern. This heterogeneity in progression makes it difficult to tailor treatment strategies for an individual patient. We aimed to identify clinicopathological factors associated with papillary thyroid carcinoma recurrence, persistence, and specific mortality. Our study supports that both pre-surgical factors, such as male gender, presence of psammoma bodies, gross extra-thyroidal extension, and lateral compartment lymph node metastases, as well as lymph vessel invasion, venous invasion, presence of necrosis, and incomplete surgical resection, should be taken into consideration regarding treatment and follow-up of PTC patients. The same is true when analysis is restricted to stage I patients. The importance of this report is to emphasize clinical and imaging pre-surgical thyroid cancer patients’ evaluation for an appropriate surgical treatment and patient prognosis.

Abstract

Papillary thyroid cancer (PTC) has an indolent nature and usually excellent prognosis. Some PTC clinicopathological features may contribute to the development of aggressive metastatic disease. In this work, we want to evaluate PTC clinicopathological features that are presurgical prognostic predictors of patients’ outcomes and find which indicators are more adequate for tailoring surgical procedures and follow-up. We studied a series of 241 PTC patients submitted to surgery. All patients’ files and histological tumor samples were reviewed. The 8th edition AJCC/UICC (American Joint Committee on Cancer/Union for International Cancer) Controlstaging system and the 2015 American Thyroid Association risk stratification system were used. Total thyroidectomy was performed in 228 patients, lymphadenectomy in 28 patients. Gross extrathyroidal extension (ETE) was present in 10 patients and 31 tumor resection margins were incomplete. Cervical lymph node metastases (LNMs) were present in 34 patients and distant metastases at diagnosis in four patients. In multivariate analysis, male gender (OR = 15.4, p = 0.015), venous invasion (OR = 16.7, p = 0.022), and lateral compartment LNM (OR = 26.7, p = 0.004) were predictors of mortality; psammoma bodies (PBs) (OR = 4.5, p = 0.008), lymph vessel invasion (OR = 6.9, p < 0.001), and gross ETE (OR = 16.1, p = 0.001) were predictors of structural disease status; male gender (OR = 2.9, p = 0.011), lymph vessel invasion (OR = 2.8, p = 0.006), and incomplete resection margins (OR = 4.6, p < 0.001) were predictors of recurrent/persistent disease. Our study supports that the factors helping to tailor patient’s surgery are male gender, presence of PBs, gross ETE, and lateral compartment LNM. Together with pathological factors, lymph vessel invasion, venous invasion, necrosis, and incomplete surgical resection, should be taken into consideration regarding treatment and follow-up of patients.

Thyroid Papillary Microtumor: Validation of the (Updated) Porto Proposal Assessing Sex Hormone Receptor Expression and Mutational BRAF Gene Status

Given the high incidence and excellent prognosis of many papillary thyroid microcarcinomas, the Porto proposal uses the designation papillary microtumor (PMT) for papillary microcarcinomas (PMCs) without risk factors to minimize overtreatment and patients' stress. To validate Porto proposal criteria, we examined a series of 190 PMC series, also studying sex hormone receptors and BRAF mutation. Our updated Porto proposal (uPp) reclassifies as PMT incidental PMCs found at thyroidectomy lacking the following criteria: (a) detected under the age of 19 years; (b) with multiple tumors measuring >1 cm adding up all diameters; and (c) with aggressive morphologic features (extrathyroidal extension, angioinvasion, tall, and/or hobnail cells). PMCs not fulfilling uPp criteria were considered "true" PMCs. A total of 102 PMCs were subclassified as PMT, 88 as PMC, with no age or sex differences between subgroups. Total thyroidectomy and iodine-131 therapy were significantly more common in PMC. After a median follow-up of 9.6 years, lymph node metastases, distant metastases, and mortality were only found in the PMC subgroup. No subgroup differences were found in calcifications or desmoplasia. Expression of estrogen receptor-α and estrogen receptor-β, progesterone receptor, and androgen receptor was higher in PMC than in nontumorous thyroid tissue. BRAF mutations were detected in 44.7% of PMC, with no differences between subgroups. In surgical specimens, the uPp is a safe pathology tool to identify those PMC with extremely low malignant potential. This terminology could reduce psychological stress associated with cancer diagnosis, avoid overtreatment, and be incorporated into daily pathologic practice.

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.

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.

Risk Factors of Metastatic Lymph Nodes in Papillary Thyroid Microcarcinoma

INTRODUCTION

Papillary thyroid microcarcinoma (PTMC) usually has an indolent course, but some have worse prognostic factors, such as the presence of central (6.9%-51.5%) and lateral (3%-49.6%) lymph node metastases. The aim of this study is to analyze the factors associated with PTMC with metastatic lymph nodes and its long-term prognosis.

METHODS

Retrospective study whose study population consists of patients with PTMC (size ≤1cm). Patients with previous thyroid surgery, other synchronous malignancies and ectopic location of the PTMC were excluded. Two groups were compared: PTMC without metastatic lymph nodes (group 1) and PTMC with metastatic lymph nodes (group 2). A multivariate analysis using a logistic regression model and a Kaplan-Meier survival analysis with log-rank test were performed.

RESULTS

Out of the 161 selected patients, 9.3% (n=15) had metastatic lymph nodes. Multifocality (OR 5.284, 95%CI 1.056-26.443; P=.043) and extrathyroidal extension (OR 7.687, 95%CI 1.405-42.050; P=.019) were associated with the presence of metastatic lymph nodes. In PTMC with metastatic lymph nodes, more aggressive treatments were performed: lymphadenectomy (4.8% vs. 100%; P<.001) and radioactive iodine (24.7% vs. 100%; P<.001). During a mean follow-up of 119.8±65 months, one recurrence was detected in group 2 (0% vs. 6.7%; P=.093). No patients died due to the disease.

CONCLUSIONS

Multifocality and extrathyroidal extension of PTMC were associated with the presence of metastatic lymph nodes. Metastatic PTMC, with more aggressive treatments, presents an excellent long-term prognosis.

Incidental versus clinical diagnosis of papillary thyroid microcarcinoma. Long-term prognosis

INTRODUCTION

The incidence of papillary thyroid microcarcinoma (PTMC) has increased in recent years, especially in patients operated on for presumably benign thyroid disease. The aim of this study was to analyze the differences between PTMC incidentally diagnosed and PTMC clinically diagnosed, as well as its long-term prognosis.

MATERIAL AND METHODS

The study population consisted of patients with a histological diagnosis of PTMC. Patients with previous thyroid surgery, other synchronous thyroid or extrathyroid malignancies and an ectopic location of PTMC were excluded. Two groups were compared: patients with PTMC incidentally diagnosed (group 1) and patients with PTMC clinically diagnosed (group 2). A multivariate analysis of differentiating factors was performed.

RESULTS

PTMC clinically diagnosed had a high frequency of hypothyroidism (4.6% vs. 18.9%; P=.004), extrathyroidal extension (5.7% vs. 17.6%; P=.018), metastatic lymph nodes (1.1% vs. 18.9%; P<.001) and lymphocytic thyroiditis (5.7% vs. 27%; P<.001). In the multivariate analysis, metastatic lymph nodes (OR: 22.011, IC 95%: 2.621-184.829; P=.004) and lymphocytic thyroiditis (OR: 4.949; IC 95%: 1.602-15.288; P=.005) were associated with the clinical diagnosis of PTMC. During a mean follow-up of 119.8±65.1 months, one recurrence was detected in group 2 (0% vs. 1,4%; P=.460). No patient died due to the disease.

CONCLUSIONS

PTMC clinically diagnosed, although it has more aggressive histopathological characteristics (extrathyroidal extension and metastatic lymph nodes), presents a long-term prognosis similar to the PTMC incidentally diagnosed. The presence of metastatic lymph nodes and lymphocytic thyroiditis were independent factors associated with PTMC clinically diagnosed.

Clinical outcomes of ultrasound-guided radiofrequency ablation for the treatment of primary papillary thyroid microcarcinoma

AIM

To evaluate the safety, efficacy, and long-term outcomes of ultrasound-guided radiofrequency ablation (RFA) for the treatment of primary papillary thyroid microcarcinoma (PTMC).

MATERIALS AND METHODS

A total of 37 patients with 38 PTMC nodules underwent RFA at a power of 20 W between September 2014 and December 2017. The clinical data of these patients were reviewed retrospectively and analysed. Imaging studies of the nodules were conducted, and the patients' thyroid function was assessed before RFA; 1, 3, 6, and 12 months after RFA; and every 6 months thereafter. The volumes and volume reduction rate (VRR) of the nodules were also calculated.

RESULTS

RFA with a low power of 20 W was used in the treatment of 37 patients with 38 PTMC nodules. All nodules achieved complete ablation, no complications occurred, and thyroid function was not affected. During follow-up, the volume of the nodules gradually decreased. Twelve months after ablation, the mean volumes of the nodules significantly decreased to 0.01±0.03 ml with a VRR of 99.34±3.49%. At a median follow-up of 6 (range: 1-18) months, 37 of the 38 nodules were completely absorbed, and no recurrence was observed in all 37 patients.

CONCLUSIONS

Low-power RFA showed good safety and promising efficacy outcomes for the treatment of PTMC. In addition to surgery and active surveillance, RFA may be an alternative treatment option for patients with PTMC.

Papillary Thyroid Microcarcinoma: Reclassification to Non-Invasive Follicular Thyroid Neoplasm with Papillary-Like Nuclear Features (NIFTP): a Retrospective Clinicopathologic Study

Papillary thyroid microcarcinoma (PTMC) accounts for nearly 50% of newly diagnosed PTC cases. There is considerable debate in literature about the clinicopathologic features and prognostic significance of PTMC and whether it should be treated as a separate entity. Due to lack of agreement and supportive data, the consensus study group that established the criteria for non-invasive thyroid neoplasm with papillary-like features (NIFTP) kept its size above 1 cm i.e., excluding PTMC from this new group. As a result, to date, some patients diagnosed with PTMC get aggressive treatments such as partial or total thyroidectomy and even radioactive iodine ablation. We retrospectively studied clinicopathologic features and long-term follow-up of 48 cases of papillary thyroid microcarcinoma. Of these, 7 cases (15%) had capsular invasion, 2 cases (4%) had extrathyroidal extension, 1 case (2%) had lymphovascular invasion, 5 cases (25%) had lymph node metastases, no case (0%) had any distant metastases, and 1 case had recurrence after long-term follow-up (mean 13.7 years, range 1-21 years). Upon slide review, 8 cases fulfilled the criteria for NIFTP and were sub-classified under this new category. These 8 cases had no recurrence after long-term follow-up (mean 12.1 years, range 7-19 years). In this study, we confirmed the previous published reports exhibiting indolent nature of PTMC and also suggested that PTMC cases that fulfill all the criteria for NIFTP can be sub-classified under this term in order to avoid unnecessary aggressive treatment.

The increasing prevalence of chronic lymphocytic thyroiditis in papillary microcarcinoma

Although the incidence of some malignancy has decreased over the recent years, this is not the case of papillary thyroid microcarcinoma (PTMC), whose incidence has increased worldwide. Most PTMC are found incidentally after histological examination of specimens from surgery for benign thyroid disease. Hashimoto's thyroiditis, whose incidence has also increased, coexists in about one in three PTMC patients. Three different mechanisms have been proposed to clarify the association between chronic lymphocytic thyroiditis and PTMC, namely tumor development/growth by: (i) TSH stimulation, (ii) expression of certain proto-oncogenes, (iii) chemokines and other molecules produced by the lymphocytic infiltrate. Whether Hashimoto's thyroiditis protects against lymph node metastasis is debated. Overall, autommune thyroiditis seems to contribute to the favorable prognosis of PTMC. Major limitations of the studies so far performed include: (i) retrospective design, (ii) limited statistical power, (iii) high risk of selection bias, (iv) and predominant Asian ethnicity of patients. Full genetic profiling of both diseases and identification of environmental factors capable to trigger them, as well as well-powered prospective studies on different ethnical groups, may help understand their causal association and why their frequencies are continuing raising.

RISK FACTORS FOR CENTRAL LYMPH NODE METASTASES IN PATIENTS WITH PAPILLARY THYROID MICROCARCINOMA

OBJECTIVES

Papillary thyroid carcinoma with a maximum tumor diameter no more than 10 mm is defined as papillary thyroid microcarcinoma (PTMC). The proportion of newly diagnosed PTMCs has increased significantly in recent years. Different guidelines have different comments about optimal management of PTMC, especially on prophylactic central lymph node (CLN) dissection. The aim of the present study was to analyze the risk factors for CLN metastases in patients with PTMC.

METHODS

A total of 4,389 patients underwent thyroid surgery at our center from January 2017 to March 2018, and 2,129 patients with PTMC were selected and assessed retrospectively. The relationship between CLN metastases and clinicopathologic features of PTMC were analyzed by both univariate and multivariate analyses.

RESULTS

Of the 2,129 patients with PTMC, CLN metastases were confirmed by pathology in 923 patients. Univariate and multivariate analyses found several independent factors associated with CLN metastases. They were male gender (odds ratio [OR], 1.694; 95% confidence interval [CI], 1.386 to 2.071; P<.001), younger age (<45 years) (OR, 2.687; 95% CI, 2.196 to 3.288; P<.001), larger tumor size (>5 mm) (OR, 2.168; 95% CI, 1.782 to 2.636; P<.001), positive CLN metastases via ultrasound (OR, 4.939; 95% CI, 3.534 to 6.902; P<.001), and multifocality (OR, 1.424; 95% CI, 1.176 to 1.724; P<.001).

CONCLUSION

CLN metastases are common in PTMC patients. Male gender, younger age (<45 years), larger tumor size (>5 mm), positive CLN metastases via ultrasound, and multifocality are independent risk factors for CLN metastases. Our data should be considered in the decision-making process related to performing CLN dissection.

ABBREVIATIONS

CLN = central lymph node; PTC = papillary thyroid carcinoma; PTMC = papillary thyroid microcarcinoma.

Trends in thyroid cancer incidence and mortality in Portugal

The objective was to quantify thyroid cancer incidence and mortality trends in Portugal. The number of thyroid cancer cases and incidence rates were retrieved from the Regional Cancer Registries for the period 1989-2011. The number of deaths and mortality rates were obtained from the WHO cancer mortality database (1988-2003 and 2007-2012) and Statistics Portugal (2004-2006; 1988-2012 by region). Joinpoint regression of the standardized incidence and mortality rates was performed. A significant, rapid and continued increase in incidence was observed for both sexes in each of the Regional Cancer Registries, with annual per cent changes (APCs) ranging between 2 and 9. Incidence in Portuguese women is higher than estimates for the world and Europe. Mortality decreased for women (APC: -1.5), with the greatest decrease in the North, and increased marginally for men (APC: +0.2), with a greater increase in the South. The significant increases in incidence in Portugal are predominantly because of the increase in incidence among women from the North. These trends, combined with an overall low mortality and high 5-year relative survival, raise concerns on the extent to which overdiagnosis may be taking place. Further research is needed, quantifying the importance of the most likely determinants of these trends as well as the extent and potentially deleterious effects of overdiagnosis and overtreatment in the Portuguese setting.

Impact of major different variants of papillary thyroid microcarcinoma on the clinicopathological characteristics: the study of 1041 cases

Background

The incidence of papillary thyroid microcarcinoma (PTMC) has been increasing globally in the past few decades. PTMC does not have a distinctive morphology that results in differences in biological behavior. The aim of this study was to classify PTMCs according to the morphological features and explore the relationship with clinicopathological characteristics. Additionally, we sought to evaluate whether different variants of PTMC can be an independent predictor for lymph mode metastasis when considering other risk factors.

Methods

Between December 2014 and December 2015, 1041 PTMC cases undergoing surgical resection at Tianjin Medical University Cancer Institute and Hospital were reviewed retrospectively. Statistical analysis was performed to investigate the independent factors for lymph node metastasis in PTMC.

Results

Conventional variant PTMC (CPTMC), follicular variant PTMC (FPTMC), and encapsulated variant PTMC (EnPTMC) were major variants in PTMC, collectively accounting for 96.7% of the entire PTMC cohort.There were significant differences in clinicopathological characteristics among the three major variants. The frequency of aggressive parameters was significantly different among the three variants, including tumor size, minimal extrathyroidal extension (minimal ETE), and lymph node metastasis (all P < 0.05), being highest in CPTMC, lowest in EnPTMC, and intermediate in FPTMC. FPTMC (OR = 0.642, P = 0.003) and EnPTMC (OR = 0.540, P = 0.041) were independent protective factors for lymph node metastasis (LNM). In contrast, male gender (OR = 1.836, P = 0.000), age less than 45 years (OR = 1.457, P = 0.009), tumor size greater than 0.5 cm (OR = 1.453, P = 0.007), calcification (OR = 1.465, P = 0.016), minimal ETE (OR = 1.801, P = 0.001), and multifocality (OR = 1.721, P = 0.000) were independent risk factors for LNM.

Conclusions

The present study demonstrates the distinct biological behaviors of the three major PTMC variants and establishes an aggressive order of CPTMC ≫ FPTMC > EnPTMC. It is necessary to take into consideration variant-related risks and other independent predictors for the determination of lymphadenectomy in patients with PTMC.

Influence of tumor extent on central lymph node metastasis in solitary papillary thyroid microcarcinomas: a retrospective study of 1092 patients

Background

The morbidity of papillary thyroid microcarcinomas is increasing worldwide. Surgery is the main treatment for papillary thyroid microcarcinomas, and the choice of surgical method partly depends on the T stage of the tumor. However, according to the American Joint Commission on Cancer staging system (7th edition), the T stage of papillary thyroid microcarcinomas with different tumor extent is unclear. We aimed to study the effect of tumor extent and other factors on central lymph node metastasis to explore the relationship between tumor extent and T stage and to identify the risk factors predicting central lymph node metastasis in papillary thyroid microcarcinomas.

Methods

We included 1092 patients diagnosed with solitary papillary thyroid microcarcinomas between July 2011 and April 2016. The tumor extent and other central lymph node metastasis risk factors were retrospectively analyzed.

Results

Univariate analysis revealed that capsule invasion and extracapsular extension (P = 0.013, <0.001; respectively) were significantly correlated with central lymph node metastasis. On multivariate analysis, extracapsular extension was independent central lymph node metastasis predictors (odds ratio 3.092, 95% CI 1.744–5.484), while capsule invasion was not (odds ratio 1.212, 95% CI 0.890–1.651). In addition, multivariate analysis revealed that male sex, tumor size >5 mm, and age <45 years were independent central lymph node metastasis predictors (odds ratio 2.072, 2.356, 2.302; 95% CI 1.483–2.894, 1.792–3.099, 1.748–3.031; respectively).

Conclusions

This study supported that capsule invasion and tumor limited to the thyroid in papillary thyroid microcarcinomas were suitable for the lower T1, that is, capsule invasion in papillary thyroid microcarcinomas might not belong to the minimal extrathyroid extension included in T3 of TNM staging. In addition, patients with risk factors of extrathyroid extension, male sex, age <45 years, or tumor size >5 mm in papillary thyroid microcarcinomas should consider a more aggressive surgical treatment.

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.

Total thyroidectomy may be more reasonable as initial surgery in unilateral multifocal papillary thyroid microcarcinoma: a single-center experience

BACKGROUND

The extent of surgery in patients with unilateral multifocal papillary thyroid microcarcinoma (UMPTMC) remains to be controversial. Aimed to improve surgical management of UMPTMC, this study was performed to identify the recurrence of UMPTMC and analyze its predictive factors.

METHODS

This study was approved by the Ethical Committee of The First Hospital of the Jilin University, and written informed consent was given by participants for their clinical records to be used in this study. We retrospectively analyzed a total of 97 consecutive patients who underwent initial surgery for the treatment of UMPTMC at The First Hospital of Jilin University, between October 2005 and October 2006.

RESULTS

Altogether, 97 patients of UMPTMC have been enrolled in our study, in which 57 cases were performed with hemithyroidectomy (HT) while other 40 cases with total thyroidectomy (TT). The sum diameter of all tumors >1 cm was more frequent in HT group than in TT group (40.35 vs 20%; p = 0.046). Positive central lymph nodes were found more frequently in the TT patients than in the HT patients (80 vs 59.65%; p = 0.046). Tumor recurrence was seen more frequently in the HT cases than in the TT cases (26 vs 5%; p = 0.007). The disease-free survival period was significantly shorter for the HT patients than for the TT patients (p = 0.0059 by the log-rank test). The disease-free survival rates at 5 and 10 years were 91.23 and 73.68%, respectively, in the HT group and 100 and 92.5%, respectively, in the TT group. Univariate analysis by Cox's proportional hazards method showed male gender, sum diameter of all tumors >1 cm, and central lymph node metastases (CLNM) to be risk factors for recurrence of HT patients. Male gender and sum diameter >1 cm were factors identified for multivariate analysis by Cox's proportional hazards method which yielded risk ratios of 3.037 [CI 1.026-8.988; p = 0.045] and 5.475 [CI 1.389-21.572; p = 0.015] in the HT group.

CONCLUSIONS

In summary, with an increased risk of recurrence, TT may be more reasonable as initial surgery in UMPTMC, especially with male gender and total tumor diameter greater than 1 cm.

BRAF V600E and decreased NIS and TPO expression are associated with aggressiveness of a subgroup of papillary thyroid microcarcinoma

BACKGROUND

Thyroid cancer incidence has dramatically increased worldwide over the last two decades. The rise is mostly due to an increased detection of small papillary thyroid carcinomas (PTCs) (≤20  mm), predominantly microPTC (≤10  mm). Although small tumors generally have an excellent outcome, a considerable percentage may have a more aggressive disease and worse prognosis. The clinical challenge is to preoperatively identify those tumors that are more likely to recur.

AIM

To improve risk stratification and patient management, we sought to determine the prognostic value of BRAF V600E, NRAS or RET/PTC mutations in patients with PTC measuring <20  mm, mainly microPTC.

METHODS

The prevalence of RET/PTC fusion genes was examined by quantitative RT-PCR. BRAF V600E and NRAS Q61 mutations were determined by PCR sequencing. To further elucidate why some small PTC are less responsive to radioactive iodine treatment therapy, we explored if these genetic alterations may modulate the expression of iodine metabolism genes (NIS, TPO, TG, TSHR and PDS) and correlated with clinico-pathological findings that are predictors of recurrence.

RESULTS

This study shows that tumors measuring ≤20  mm exhibited higher prevalence of BRAF V600E mutation, which correlated with aggressive histopathological parameters, higher risk of recurrence, and lower expression of NIS and TPO. Although this correlation was not found when microPTC were evaluated, we show that tumors measuring 7-10  mm, which were positive for BRAF mutation, presented more aggressive features and lower expression of NIS and TPO.

CONCLUSION

We believe that our findings will help to decide the realistic usefulness of BRAF V600E mutation as a preoperative marker of poor prognosis in small PTC, primarily in microPTC.

Genetic Alterations in Hungarian Patients with Papillary Thyroid Cancer

The incidence of thyroid cancers is increasing worldwide. Some somatic oncogene mutations (BRAF, NRAS, HRAS, KRAS) as well as gene translocations (RET/PTC, PAX8/PPAR-gamma) have been associated with the development of thyroid cancer. In our study, we analyzed these genetic alterations in 394 thyroid tissue samples (197 papillary carcinomas and 197 healthy). The somatic mutations and translocations were detected by Light Cycler melting method and Real-Time Polymerase Chain Reaction techniques, respectively. In tumorous samples, 86 BRAF (44.2%), 5 NRAS (3.1%), 2 HRAS (1.0%) and 1 KRAS (0.5%) mutations were found, as well as 9 RET/PTC1 (4.6%) and 1 RET/PTC3 (0.5%) translocations. No genetic alteration was seen in the non tumorous control thyroid tissues. No correlation was detected between the genetic variants and the pathological subtypes of papillary cancer as well as the severity of the disease. Our results are only partly concordant with the data found in the literature.

Two-dimensional shear wave elastography as promising diagnostic tool for predicting malignant thyroid nodules: a prospective single-centre experience

OBJECTIVES

To evaluate the diagnostic performance of two-dimensional shear wave elastography (2D-SWE) in distinguishing malignant from benign thyroid nodules.

METHODS

A total of 331 focal thyroid nodules from 271 patients scheduled for fine-needle aspiration or thyroid surgery were included. After a routine conventional ultrasound evaluation, 2D-SWE examinations were performed to obtain 2D-SWE measurements on a colour-coded mapping, which were then correlated with pathology results.

RESULTS

A total of 230 nodules were benign and 101 were malignant on pathology. The areas under the receiver operating characteristic curve (AUC) of mean and minimum values in the largest region of interest (ROI) over the whole nodule, and mean, maximum and minimum values in 2-mm ROI over the stiffest area of the nodule were 0.794, 0.673, 0.808, 0.805 and 0.799, respectively. The most accurate cut-off value, 39.3 kPa, for mean value in a 2-mm ROI achieved 66.3 % sensitivity and 84.4 % specificity to discriminate malignancy. Nodule size correlated with 2D-SWE value for malignant nodules (P < 0.01). In the group of nodules ≤10 mm, the AUC was 0.730, while it was 0.883 in nodules sized 11-30 mm and 0.821 in nodules >30 mm.

CONCLUSION

2D-SWE is a promising diagnostic tool for discriminating malignant thyroid nodules, although the performance for nodules ≤10 mm is not satisfactory.

Clinical outcome in differentiated thyroid carcinoma and microcarcinoma

INTRODUCTION

Due to the frequent use of neck ultrasonography, the incidence of differentiated thyroid microcarcinoma (DTMC), defined as a lesion with greatest dimension ≤1 cm, is increasing worldwide. Although DTMC generally has a lower aggressivity and a better prognosis than differentiated thyroid carcinoma (DTC), some cases of clinically aggressive DTMC were found. The aim of this study is to compare the rate of recurrence in DTMC and DTC, during a 3-year follow-up.

METHODS

Patients with differentiated thyroid carcinoma, who underwent total thyroidectomy and postoperative (131)I-RAI ablation, were stratified according to lesion diameter (DTC for diameter > 1 cm or DTMC ≤ 1 cm). After surgery, patients underwent a 3-year follow-up. Recurrent disease was defined on the basis of positive biochemical (Tg > 2 ng/ml under TSH-suppression or after rhTSH-stimulation) and/or imaging (US, WBS, CT, PET/CT) findings.

RESULTS

449 patients have been included in the final analysis. Linfoadenectomy rate and RAI ablative dose were significantly higher in DTC than in DTMC (32.7% vs. 22.4%, p = 0.018 and 112.3 ± 21 vs. 68.3 ± 24.1 mCi, p < 0.001). During the follow-up, 50 carcinoma recurrences occurred, more frequent in DTC than in DTMC (15.6% vs. 7.6%, p = 0.010). After adjustment for gender, age, rate of lymph node dissection and 131I dose of RAI treatment, the difference in the risk of recurrence was no longer significant among DTC and DTMC patients (HR: 1.585, 95% CI 0874-2877, p = 0.130).

CONCLUSIONS

The prediction of disease severity cannot be based exclusively on lesion diameter. A more careful therapeutic approach and follow-up should be recommended in DTMC patients.

Shear wave elastography versus real-time elastography on evaluation thyroid nodules: a preliminary study

OBJECTIVE

To comparatively evaluate shear wave elastography (SWE) and real-time elastography (RTE) in distinguishing malignant from benign thyroid nodules.

METHODS

49 patients with 64 focal thyroid nodules were enrolled and underwent SWE and RTE before surgery. SWE elasticity indices (mean, minimum and maximum value of 2-mm region of interest) of nodules were measured. For RTE, elastograms were assessed by Rago criteria and nodules with scores of 4 or 5 were classified as suspicious for malignancy. Surgery histopathologic results were adopted as diagnostic standard.

RESULTS

Of the 64 nodules, 19 were papillary thyroid carcinomas and 45 were benign. SWE indices were significantly higher in malignant than benign nodules (P<0.05). Areas under the ROC curves (AUC) of SWE parameters were 0.840, 0.831 and 0.788, which were not significantly different from that of RTE showed as 0.880 (P=0.148-0.482). When the most accurate cut-off, 38.3kPa for mean value was applied to predict malignancy, the diagnostic specificity, sensitivity, accuracy, positive predictive value and negative predictive value of SWE and RTE were 68.4% versus 79.0%, 86.7% versus 84.4%, 81.3% versus 78.1%, 68.4% versus 64.7% and 86.7% versus 83.3%, respectively (P=0.683-1.000).

CONCLUSION

SWE as a promising tool can be performed in differentiating thyroid nodules with comparable results to RTE.