Radiofrequency ablation is an effective treatment for Bethesda III thyroid nodules without genetic alterations

Background

Radiofrequency ablation (RFA) is effective in the treatment of thyroid nodules, leading to a 50-90% reduction with respect to baseline. Current guidelines indicate the need for a benign cytology prior to RFA, though, on the other side, this procedure is also successfully used for the treatment of papillary microcarcinomas. No specific indications are available for nodules with an indeterminate cytology (Bethesda III/IV).

Aim

To evaluate the efficacy of RFA in Bethesda III nodules without genetic alterations as verified by means of a custom panel.

Methods

We have treated 33 patients (mean delivered energy 1069 ± 1201 J/mL of basal volume) with Bethesda III cytology, EU-TIRADS 3-4, and negative genetic panel. The mean basal nodular volume was 17.3 ± 10.7 mL.

Results

Considering the whole series, the mean volume reduction rate (VRR) was 36.8 ± 16.5% at 1 month, 59.9 ± 15.5% at 6 months, and 62 ± 15.7% at 1-year follow-up. The sub-analysis done in patients with 1 and 2 years follow-up data available (n = 20 and n = 5, respectively) confirmed a progressive nodular volume decrease. At all-time points, the rate of reduction was statistically significant (P < 0.0001), without significant correlation between the VRR and the basal volume. Neither cytological changes nor complications were observed after the procedure.

Conclusion

RFA is effective in Bethesda III, oncogene-negative nodules, with reduction rates similar to those obtained in confirmed benign lesions. This procedure represents a good alternative to surgery or active surveillance in this particular class of nodules, regardless of their initial volume. A longer follow-up will allow to evaluate further reduction or possible regrowth.

Reappraising the role of thyroid scintigraphy in the era of TIRADS: A clinically-oriented viewpoint

Thyroid nodules (TNs) are a common entity, with the majority being benign. Therefore, employing an accurate rule-out strategy in clinical practice is essential. In the thyroid field, the current era is significantly marked by the worldwide diffusion of ultrasound (US)-based malignancy risk stratification systems of TN, usually reported as Thyroid Imaging Reporting And Data System (TIRADS). With the advent of US (and later TIRADS), the role of thyroid scintigraphy (TS) in clinical practice has gradually diminished. The authors of the present paper believe that the role of TS should be reappraised, also considering its essential role in detecting autonomously functioning thyroid nodules and its limited contribution to detecting thyroid cancers. Thus, this document aims to furnish endocrinologists, radiologists, surgeons, and nuclear medicine physicians with practical information to appropriately use TS.

Could Transplantation into the Thyroid Gland Benefit Pancreatic Islet Grafting in Unstable Type 1 Diabetes (T1DM), Complicated Type 2 Diabetes (T2DM), and Patients with Total Pancreatectomy?

BACKGROUND

Insular allograft for unstable type 1 diabetes and autograft in pancreatectomy patients are nowadays considered established procedures with precise indications and predictable outcomes. The clinical outcome of islet transplantation is similar to that of pancreas transplantation, avoiding the complications associated with organ transplantation.

OBJECTIVE

We hypothesised that transplantation of islets of Langerhans within an endocrine organ could better promote their engraftment and function. This could help to resolve or ameliorate known pathological conditions such as unstable type 1 diabetes and complicated type 2 diabetes.

RATIONALE

Pancreatic islet transplantation is currently performed almost exclusively in the liver. The liver provides a sufficiently favourable environment, although not entirely. The hepatic parenchyma has a lower oxygen tension than the pancreatic parenchyma and the vascular structure of the liver is not typical of an exclusively endocrine organ. Moreover, islet transplantation into the liver is not without complications, including hematoma or portal vein thrombosis.

PROPOSED PROJECT

The thyroid gland is the endocrine gland proposed as a 'container'. In fact, it has all the characteristics of 'physio-compatibility' which can address the objectives assumed. It is indeed an ideal site because it is an easily accessible anatomical site that allows islets to be implanted using ultrasound-guided transcutaneous inoculation technique. Moreover, it has physiological and anatomical endocrine affinities with pancreatic islets and, if necessary, it can be removed, using hormone supplementation or replacement therapy.

CONCLUSIONS

The thyroid gland may be proposed as an ideal site for islet implantation due to its anatomical and physiocompatibility characteristics.

Clinical Outcomes of Thermal Ablation Re-Treatment of Benign Thyroid Nodules: A Multicenter Study from the Italian Minimally Invasive Treatments of the Thyroid Group

Background: Thermal ablation (TA) is an established therapeutic option alternative to surgery in patients with solid benign thyroid nodules causing local symptoms. However, a variable part of thyroid nodules remain viable after these nonsurgical treatments, and as many as 15% of nodules treated with TA may require a second treatment over time. This study aimed to evaluate the outcomes of TA re-treatment on symptomatic benign thyroid nodules where the volume decreased by <50% after the first procedure ( = technique inefficacy). Methods: We performed a multicenter retrospective cohort study including patients who underwent re-treatment with TA for benign thyroid nodules, whose volume decreased by <50% after initial treatment. The primary aim was to evaluate volume and volume reduction ratio (VRR) over time and compare the 6- and 12-month VRR after first versus second treatment. The secondary aim was to identify protective or risk factors for technique inefficacy, regrowth, and further treatments, expressed as adjusted hazard ratios (HRs) and confidence interval [CI], after adjustment for sex, age, nodule volume, structure and function, nodule regrowth or symptom relapse, technique used and if the same technique was used for the first and second TA and time between them. Results: We included 135 patients. Re-treatment led to VRR of 50% and 52.2% after 6 and 12 months. VRR after re-treatment was greater than after first treatment in small and medium size nodules (<30 mL), while there were no differences for large nodules (>30 mL). After re-treatment technique inefficacy rate was 51.9%, regrowth rate was 12.6%, and further treatment rate was 15.6%. Radiofrequency ablation (RFA) was protective toward technique inefficacy (HR = 0.40 [CI 0.24-0.65]) and need of further treatments (HR = 0.30 [CI 0.12-0.76]). Large nodule volume (>30 mL) was associated with increased risk of re-treatment (HR = 4.52 [CI 1.38-14.82]). Conclusions: This is the first study evaluating the outcomes of re-treatment on symptomatic benign thyroid nodules with a VRR <50% after the initial TA treatment. Best results were seen in small and medium nodules (<30 mL) and after RFA. Prospective confirmatory studies are needed.

Preoperative neck ultrasound combined with pathological data can significantly impact the outcome of medullary thyroid carcinoma

The diagnosis of medullary thyroid carcinoma (MTC) is challenging since the accuracy of ultrasound (US) and fine-needle aspiration cytology are suboptimal. As a result, MTC has a generally poor prognosis. The aim of this study was to analyze whether perioperative data can modify the risk of relapse in these patients. The institutional database of Turin Mauriziano Hospital was searched to extract records of MTCs diagnosed between 2000 and 2021. Kaplan-Meier curves and Cox and logistic regression analyses were performed, and the hazard ratio (HR) was calculated. Seventy-three MTC patients (median age 58 yr) were found. Disease-free survival was significantly different according to staging (HR: 9.12; p = 0.037), capsular status (HR: 5.49; p = 0.02), and neck US (HR: 9.19; p = 0.04). In the logistic regression analysis, CEA level (β: -0.01; p = 0.043), histological multifocality (OR: 7.4; p = 0.034), and metastatic lymph nodes at histology (β: -0.13; p = 0.006) were significantly associated with structural recurrence. Two logistic multivariate models best explained the variance in recurrence: 1) neck US presentation plus histological multifocality (AIC: 27; r2: 0.37; x2: 12.4; p = 0.002) and 2) number of neck metastases plus capsular invasion (AIC: 26; r2: 0.40; x2: 13.7; p = 0.001). Pathological data are associated with MTC prognosis. Preoperative neck US can significantly help to predict MTC outcome.

Treating intra-thyroid parathyroid adenoma by radiofrequency is a valuable alternative to hemithyroidectomy

BACKGROUND

Parathyroid adenoma (PA) is the most common cause of primary hyperparathyroidism (PHPT). One infrequent scenario (0.7%-6%) is represented by intra-thyroid PA (I-PA), an ectopic variant of the parathyroid gland included in the thyroid parenchyma. Radiofrequency (RF) of I-PA seems to be an excellent alternative to hemithyroidectomy for these patients. The present study aimed to report three cases of PHPT and I-PA treated with RF at two institutions.

MATERIALS AND METHODS

These two institutions share guidelines for thyroid RF. At both institutions, cases with surgical indication and difficult PA localization are discussed during thyroid multidisciplinary meetings involving all disciplines involved in managing these cases. RF was performed using a Viva RF System generator (STARMED). Ultrasound contrast evaluation was performed using a SonoVue (Bracco). All patients were followed-up by an expert endocrinologist.

RESULTS

Three cases had indications for treating I-PA. All patients were proposed to undergo RF rather than hemithyroidectomy, and accepted this option. RF of I-PA was performed with a power of 30-50 W and delivering a total between 0.02 and 0.69 Kcal. The active treatment lasted just more than 1 min. Post-treatment follow-up revealed PTH and calcium normalization.

CONCLUSION

This study showed highly encouraging results in favor of treating I-PA with RF.

A Prospective Multicenter Study Examining the Relationship Between Thyroid Cancer Treatment Outcomes and the Presence of Autoimmune Thyroiditis

Background: There is some controversy on the potential relationship between autoimmune processes and clinicopathologic features as well as prognosis of differentiated thyroid cancer (DTC), and the evidence is limited by its largely retrospective nature. We examined the relationship between the presence of autoimmune thyroiditis (AT) and 1-year thyroid cancer treatment outcomes in a large multicenter study using prospectively collected data. Methods: We included data from consecutive DTC patients enrolled in the Italian Thyroid Cancer Observatory (ITCO) database (NCT04031339). We divided the groups according to the presence (AT) or absence (no autoimmune thyroiditis [noAT]) of associated AT. We used propensity score matching to compare the clinical features and outcomes between the two groups at 1-year follow-up. Results: We included data from 4233 DTC patients, including 3172 (75%) females. The American Thyroid Association (ATA) risk levels were as follows: 51% (2160/4233) low risk, 41.3% (1750/4233) intermediate risk, and 7.6% (323/4233) high risk. There were 1552 patients (36.7%) who had AT. Before propensity score matching, AT patients were significantly younger and had a smaller and bilateral tumor (p < 0.0001). Patients with AT more frequently fell into the low- and intermediate-risk categories, while the ATA high risk was more frequent among noAT patients (p = 0.004). After propensity score matching, patients with AT more frequently showed evidence of disease (structural/biochemical incomplete response) versus excellent/indeterminate response, compared with patients without AT (7.3% vs. 4.5%, p = 0.001), with an odds ratio of 1.86 ([confidence interval: 1.3-2.6], p = 0.0001). However, when considering only structural persistence as the outcome, no statistically significant differences were observed between patients with or without AT (3.4% vs. 2.7%, p = 0.35). The elevated risk associated with the ATA intermediate and high risk at diagnosis remained consistently statistically significant. Conclusions: In this large prospective series, biochemical persistence was more frequent, at 1-year follow-up, in AT patients. However, there was no significant association between the presence of AT and structural persistence of disease. These findings may be explained by the presence of a residual thyroid tissue.

A Data-Driven Approach to Refine Predictions of Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study

CONTEXT

The risk stratification of patients with differentiated thyroid cancer (DTC) is crucial in clinical decision making. The most widely accepted method to assess risk of recurrent/persistent disease is described in the 2015 American Thyroid Association (ATA) guidelines. However, recent research has focused on the inclusion of novel features or questioned the relevance of currently included features.

OBJECTIVE

To develop a comprehensive data-driven model to predict persistent/recurrent disease that can capture all available features and determine the weight of predictors.

METHODS

In a prospective cohort study, using the Italian Thyroid Cancer Observatory (ITCO) database (NCT04031339), we selected consecutive cases with DTC and at least early follow-up data (n = 4773; median follow-up 26 months; interquartile range, 12-46 months) at 40 Italian clinical centers. A decision tree was built to assign a risk index to each patient. The model allowed us to investigate the impact of different variables in risk prediction.

RESULTS

By ATA risk estimation, 2492 patients (52.2%) were classified as low, 1873 (39.2%) as intermediate, and 408 as high risk. The decision tree model outperformed the ATA risk stratification system: the sensitivity of high-risk classification for structural disease increased from 37% to 49%, and the negative predictive value for low-risk patients increased by 3%. Feature importance was estimated. Several variables not included in the ATA system significantly impacted the prediction of disease persistence/recurrence: age, body mass index, tumor size, sex, family history of thyroid cancer, surgical approach, presurgical cytology, and circumstances of the diagnosis.

CONCLUSION

Current risk stratification systems may be complemented by the inclusion of other variables in order to improve the prediction of treatment response. A complete dataset allows for more precise patient clustering.

Continuous subcutaneous rhPTH infusion for managing difficult chronic hypoparathyroidism. A systematic review

PURPOSE

Standard treatment for chronic hypoparathyroidism is represented by long-life per os supplementation of calcium and vitamin D. Since 90s, exogenous PTH is also available, but a not negligible number of patients experience a poor control. Starting from the experience with pumps in diabetes, it has been hypothesized that the infusion of PTH through pump might result in a better disease control. The aim of this systematic review is to summarize the published data about continuous subcutaneous PTH infusion in chronic hypoPTH patients and achieve conclusions for clinical practice.

METHODS

A comprehensive computer literature search of the PubMed/MEDLINE, Embase, and Scopus databases was conducted by two authors independently (last search on November 30, 2022). All findings were summarized and critically discussed.

RESULTS

We included 14 of the 103 retrieved articles, 2 RCTs, 8 case reports, and 4 case series, published between 2008 and 2022. Of the total 40 patients, 17 were adults, and 23 pediatric. The etiology was postsurgical in 50% of cases and genetic in the other 50%. All had a failure of standard care and a rapid improvement of clinical and biochemical parameters on PTH pump therapy, without severe adverse events.

CONCLUSIONS

Based on literature, pump PTH infusion may represent an effective, safe, and feasible option for patients with chronic hypoparathyroidism refractory to standard therapy. From a clinical perspective, careful patient selection, a skilled healthcare team, the assessment of the local setting and the collaboration with pump suppliers are essential.

Italian Guidelines for the Management of Non-Functioning Benign and Locally Symptomatic Thyroid Nodules

AIM

This guideline (GL) is aimed at providing a reference for the management of non-functioning, benign thyroid nodules causing local symptoms in adults outside of pregnancy.

METHODS

This GL has been developed following the methods described in the Manual of the National Guideline System. For each question, the panel appointed by Associazione Medici Endocrinology (AME) identified potentially relevant outcomes, which were then rated for their impact on therapeutic choices. Only outcomes classified as "critical" and "important" were considered in the systematic review of evidence and only those classified as "critical" were considered in the formulation of recommendations.

RESULTS

The present GL contains recommendations about the respective roles of surgery and minimally invasive treatments for the management of benign symptomatic thyroid nodules. We suggest hemithyroidectomy plus isthmectomy as the first-choice surgical treatment, provided that clinically significant disease is not present in the contralateral thyroid lobe. Total thyroidectomy should be considered for patients with clinically significant disease in the contralateral thyroid lobe. We suggest considering thermo-ablation as an alternative option to surgery for patients with a symptomatic, solid, benign, single, or dominant thyroid nodule. These recommendations apply to outpatients, either in primary care or when referred to specialists.

CONCLUSION

The present GL is directed to endocrinologists, surgeons, and interventional radiologists working in hospitals, in territorial services, or private practice, general practitioners, and patients. The available data suggest that the implementation of this GL recommendations will result in the progressive reduction of surgical procedures for benign thyroid nodular disease, with a decreased number of admissions to surgical departments for non-malignant conditions and more rapid access to patients with thyroid cancer. Importantly, a reduction of indirect costs due to long-term replacement therapy and the management of surgical complications may also be speculated.

Suboptimal accuracy of ultrasound and ultrasound-based risk stratification systems in detecting medullary thyroid carcinoma should not be overlooked. Findings from a systematic review with meta-analysis

OBJECTIVE

Ultrasound (US) is the pivotal procedure during the diagnostic work-up of thyroid nodule and several US-based risk stratification systems (RSSs) have been recently developed. Since the performance of RSSs in detecting medullary thyroid carcinoma (MTC) has been rarely investigated, the present systematic review aimed to achieve high evidence about (1) how MTC is classified according to RSSs; (2) if RSSs correctly classify MTC at high risk/suspicion, and (3) if MTC is classified as suspicious at US when RSSs are not used.

DESIGN

The review was performed according to MOOSE. The online search was performed by specific algorithm on January 2022. A random-effects model was used for statistical analysis.

RESULTS

Twenty-five papers were initially included and their risk of bias was generally low. According to ATA system, 65% of MTCs was assessed at high suspicion and 25% at intermediate suspicion. Considering all RSSs, a 54.8% of MTCs was put in a high-risk/suspicion category. Pooling data from studies without data of RSS the prevalence of ultrasonographically suspicious MTCs was 60%.

CONCLUSIONS

As conclusion, MTC presentation according to RSSs is partially known and it is classified in a high-risk/suspicion category of RSSs in just over a half of cases. This advises for further studies, ideally supported by international societies, to better define the US presentation of MTC.

Long-term efficacy and safety of percutaneous ethanol injection (PEI) in cystic thyroid nodules: A systematic review and meta-analysis

BACKGROUND

Percutaneous ethanol injection (PEI) is used for the treatment of benign cystic thyroid nodules. This systematic review and meta-analysis aimed to obtain strong evidence of its long-term efficacy and safety.

METHODS

PubMed, CENTRAL, Scopus and Web of Science databases were searched until November 2020 for studies reporting data on volume reduction rate (VRR), compressive symptoms and cosmetic concerns. Associated complications were assessed. A random-effects model was designed to pool the data.

RESULTS

Out of 385 papers, nine studies evaluating 1667 nodules were finally included. Overall, VRR at 6, 12, 24, 36, 60 and 120 months was 77%, 81%, 72%, 68%, 74% and 69%, respectively. Significant reductions in the compressive symptoms and cosmetic concerns were observed. No permanent complications were observed.

CONCLUSIONS

The present meta-analysis showed that PEI could significantly reduce the volume of benign cystic thyroid nodules. This reduction was already effective at 6 months post-treatment, and the effect was stable over time.

Head-to-head comparison of FNA cytology vs. calcitonin measurement in FNA washout fluids (FNA-CT) to diagnose medullary thyroid carcinoma. A systematic review and meta-analysis

PURPOSE

The sensitivity of cytology after fine needle aspiration (FNA-cytology) in detecting medullary thyroid carcinoma (MTC) is low. To overcome this problem, measuring calcitonin (CT) in washout fluid of FNA (FNA-CT) has been largely diffused and showed good performance. However, no evidence-based study exists comparing systematically the sensitivity of FNA-cytology and FNA-CT. This study aimed to systematically review the literature and collect data allowing a head-to-head comparison meta-analysis between FNA-cytology and FNA-CT in detecting MTC lesions.

METHODS

The online databases of PubMed/MEDLINE and Scopus were searched until June 2021. Original articles reporting the use of both FNA-cytology and FNA-CT in the same series of histologically proven MTC lesions were included They were extracted general features of each study, number of MTC lesions (nodule and neck lymph nodes), and true positive and false negatives of both FNA-cytology and FNA-CT.

RESULTS

Six studies were included. The sensitivity of FNA-cytology varied from 20% to 86% with a pooled value of 54% (95% CI 35-73%) and significant heterogeneity. The sensitivity of FNA-CT was higher than 95% in almost all studies with a pooled value of 98% (95% CI 96-100%) without heterogeneity. The sensitivity of FNA-CT was significantly higher than that of FNA-cytology.

CONCLUSIONS

FNA-CT is significantly more sensitive than FNA-cytology in detecting MTC. Accordingly, FNA-CT represents the standard method to use in patients with suspicious MTC lesions, combined with cytology.

Minimal Extrathyroidal Extension in Predicting 1-Year Outcomes: A Longitudinal Multicenter Study of Low-to-Intermediate-Risk Papillary Thyroid Carcinoma (ITCO#4)

Background: The role of minimal extrathyroidal extension (mETE) as a risk factor for persistent papillary thyroid carcinoma (PTC) is still debated. The aims of this study were to assess the clinical impact of mETE as a predictor of worse initial treatment response in PTC patients and to verify the impact of radioiodine therapy after surgery in patients with mETE. Methods: We reviewed all records in the Italian Thyroid Cancer Observatory database and selected 2237 consecutive patients with PTC who satisfied the inclusion criteria (PTC with no lymph node metastases and at least 1 year of follow-up). For each case, we considered initial surgery, histological variant of PTC, tumor diameter, recurrence risk class according to the American Thyroid Association (ATA) risk stratification system, use of radioiodine therapy, and initial therapy response, as suggested by ATA guidelines. Results: At 1-year follow-up, 1831 patients (81.8%) had an excellent response, 296 (13.2%) had an indeterminate response, 55 (2.5%) had a biochemical incomplete response, and 55 (2.5%) had a structural incomplete response. Statistical analysis suggested that mETE (odds ratio [OR] 1.16, p = 0.65), tumor size >2 cm (OR 1.45, p = 0.34), aggressive PTC histology (OR 0.55, p = 0.15), and age at diagnosis (OR 0.90, p = 0.32) were not significant risk factors for a worse initial therapy response. When evaluating the combination of mETE, tumor size, and aggressive PTC histology, the presence of mETE with a >2 cm tumor was significantly associated with a worse outcome (OR 5.27 [95% confidence interval], p = 0.014). The role of radioiodine ablation in patients with mETE was also evaluated. When considering radioiodine treatment, propensity score-based matching was performed, and no significant differences were found between treated and nontreated patients (p = 0.24). Conclusions: This study failed to show the prognostic value of mETE in predicting initial therapy response in a large cohort of PTC patients without lymph node metastases. The study suggests that the combination of tumor diameter and mETE can be used as a reliable prognostic factor for persistence and could be easily applied in clinical practice to manage PTC patients with low-to-intermediate risk of recurrent/persistent disease.

Image-guided thermal ablation in autonomously functioning thyroid nodules. A retrospective multicenter three-year follow-up study from the Italian Minimally Invasive Treatment of the Thyroid (MITT) Group

OBJECTIVES

To report the results of a multicenter retrospective evaluation of the clinical outcomes of thermal ablation (TA) in a large series of autonomously functioning thyroid nodules (AFTN) with a follow-up protracted up to 3 years.

METHODS

Patients treated with single TA for an AFTN in Italy were included. Changes in nodule volume, TSH values, and ongoing anti-thyroid therapy were assessed at the 2-, 6-, 12-, 24-, and 36-month follow-up controls. Complications and need of any additional therapy after TA were also registered.

RESULTS

A total of 361 patients (244 females, 117 males, median age 58 years, IQR 46-70 years) were included. Nodule volume was significantly reduced at all time points (p < 0.001) (median volume reduction 58% at 6-month and 60% at 12-month). Serum TSH values increased significantly at all time points. After TA, anti-thyroid therapy was withdrawn in 32.5% of patients at 2 months, in 38.9% at 6 months, and in 41.3% at 12 months. A significant difference in the rate of patients who withdrawn medical therapy at 12 months was registered between small (< 10 mL) (74%), medium (49%), or large (> 30 mL) nodules (19%). A single major complication occurred (0.25%). Additional treatments were needed in 34/361 (9.4%) of cases including 4 (1.1%) surgical treatment.

CONCLUSIONS

Image-guided thermal ablation offers a further safe and effective therapeutic option in patients with AFTN. Clinical outcomes are significantly more favorable in small than in large size AFTN.

KEY POINTS

• Thermal ablations (TA) can be safely and effectively used in patients with autonomously functioning thyroid nodules (AFTN). • TA results in a clinically significant nodule volume reduction that is paralleled by TSH level normalization and anti-thyroid drug therapy discontinuation (after TA anti-thyroid therapy was withdrawn in 41.3% at 12 months). • Clinical outcomes after TA are more favorable in small nodules, and when a large amount of thyroid nodule tissue is ablated.

Graves' orbitopathy: a multidisciplinary approach

Orbitopathy is the main extra thyroidal manifestation of Graves' disease. It is a very challenging condition, which requires a cooperation between many specialists (endocrinologists, ophthalmologists, radiologists, radiotherapeutic, orbital surgeons) for an optimal clinical management. An accurate diagnostic assessment is required, in order to plan an adequate treatment of Graves' orbitopathy. Medical therapy, radiotherapy or surgery may be necessary to control the disease. In this review, the authors analyze the various therapeutic strategies, as well the more recent therapies based on pharmacologic immunomodulation.

Real-World Performance of the American Thyroid Association Risk Estimates in Predicting 1-Year Differentiated Thyroid Cancer Outcomes: A Prospective Multicenter Study of 2000 Patients

Background: One of the most widely used risk stratification systems for estimating individual patients' risk of persistent or recurrent differentiated thyroid cancer (DTC) is the American Thyroid Association (ATA) guidelines. The 2015 ATA version, which has increased the number of patients considered at low or intermediate risk, has been validated in several retrospective, single-center studies. The aims of this study were to evaluate the real-world performance of the 2015 ATA risk stratification system in predicting the response to treatment 12 months after the initial treatment and to determine the extent to which this performance is affected by the treatment center in which it is used. Methods: A prospective cohort of DTC patients collected by the Italian Thyroid Cancer Observatory web-based database was analyzed. We reviewed all records present in the database and selected consecutive cases that satisfied inclusion criteria: (i) histological diagnosis of DTC, with the exclusion of noninvasive follicular thyroid neoplasm with papillary-like nuclear features; (ii) complete data of the initial treatment and pathological features; and (iii) results of 1-year follow-up visit (6-18 months after the initial treatment), including all data needed to classify the estimated response to treatment. Results: The final cohort was composed of 2071 patients from 40 centers. The ATA risk of persistent/recurrent disease was classified as low in 1109 patients (53.6%), intermediate in 796 (38.4%), and high in 166 (8.0%). Structural incomplete responses were documented in only 86 (4.2%) patients: 1.5% in the low-risk, 5.7% in the intermediate-risk, and 14.5% in the high-risk group. The baseline ATA risk class proved to be a significant predictor of structural persistent disease, both for intermediate-risk (odds ratio [OR] 4.67; 95% confidence interval [CI] 2.59-8.43) and high-risk groups (OR 16.48; CI 7.87-34.5). Individual center did not significantly influence the prediction of the 1-year disease status. Conclusions: The ATA risk stratification system is a reliable predictor of short-term outcomes in patients with DTC in real-world clinical settings characterized by center heterogeneity in terms of size, location, level of care, local management strategies, and resource availability.

Determining an energy threshold for optimal volume reduction of benign thyroid nodules treated by radiofrequency ablation

OBJECTIVES

Radiofrequency ablation (RFA) is effective in reducing the volume of benign thyroid nodules. However, what parameters can influence the response to RFA is still unclear. The present study aimed to (1) investigate which ultrasound and technical parameters are potential determinants of the volumetric reduction; (2) develop a dose-response model, and (3) analyze the effects of RFA on ultrasound features.

METHODS

In this retrospective study, three institutions treated patients with benign thyroid nodules according to the same protocol. The technical parameters were power and energy. The 1-year volume reduction ratio (VRR) was the reference standard of the response. The correlations of different parameters with VRR were analyzed and the association between several parameters and a VRR above 50% studied by uni- and multivariate analyses. The probit regression estimated the probability to achieve an effective response.

RESULTS

One hundred fifteen patients were enrolled. The median power was 50 W and median total delivered energy 27,531 J. At 1-year follow-up, the median VRR was 64.0% and 87 (75.7%) nodules showed a VRR above 50%. Among all parameters, only baseline volume, total energy, and energy per volume were independently associated to a VRR > 50% (p = 0.001, p = 0.0178, p < 0.001 respectively). The probit regression analysis demonstrated that delivering 756 J/ml and 2670 J/ml gave a probability of VRR > 50% in 50% and 99% of patients, respectively.

CONCLUSIONS

Considering the baseline nodular volume and delivering the adequate energy per volume allow optimizing technical and clinical success.

KEY POINTS

• The effectiveness of radiofrequency ablation in treating benign thyroid nodules is negatively correlated to the volume of the nodule and positively correlated to the energy delivered per volume. • When planning the treatment, the total energy to deliver can be calculated by using a simple formula: nodular volume × 2670 J.

Five-Year Results of Radiofrequency and Laser Ablation of Benign Thyroid Nodules: A Multicenter Study from the Italian Minimally Invasive Treatments of the Thyroid Group

Background: Radiofrequency ablation (RFA) and laser ablation (LA) are effective treatments for benign thyroid nodules. Due to their relatively recent introduction into clinical practice, there are limited long-term follow-up studies. This study aimed to evaluate technique efficacy, rate of regrowth, and retreatment over 5 years after RFA or LA and to identify predictive factors of outcome. Methods: In this multicenter retrospective study, the rates of technique efficacy, regrowth, and retreatment were evaluated in 406 patients treated with either RFA or LA, and followed for 5 years after initial treatment. Propensity score matching was used to compare treatments. Cumulative incidence studies with hazard models were used to describe regrowth and retreatment trends, and to identify prognostic factors. Logistic regression models and receiver operating characteristic analyses were used for risk factors and their cutoffs. Results: RFA and LA significantly reduced benign thyroid nodule volume, and this reduction was generally maintained for 5 years. Technique efficacy (defined as a reduction ≥50% after 1 year from the treatment) was achieved in 74% of patients (85% in the RFA and 63% in the LA group). Regrowth occurred in 28% of patients (20% in the RFA and 38% in the LA group). In the majority of cases, further treatment was not required as only 18% of patients were retreated (12% in the RFA and 24% in the LA group). These data were confirmed by propensity score matching. Cumulative incidence studies showed that RFA was associated with a lower risk of regrowth and a lower risk of requiring retreatment over time. Overall, technique inefficacy and regrowth were associated with low-energy delivery. Retreatments were more frequent in young patients, in large nodules, in patients with lower volume reduction at 1 year, and in cases of low-energy delivery (optimal cutoff was 918 J/mL for RFA). Conclusions: Both thermal ablation techniques result in a clinically significant and long-lasting volume reduction of benign thyroid nodules. The risk of regrowth and needing retreatment was lower after RFA. The need for retreatment was associated with young age, large baseline volume, and treatment with low-energy delivery.

Twelve-Month Volume Reduction Ratio Predicts Regrowth and Time to Regrowth in Thyroid Nodules Submitted to Laser Ablation: A 5-Year Follow-Up Retrospective Study

Objective

Laser ablation is a therapeutic modality used to reduce the volume of large benign thyroid nodules. Unsatisfactory reduction and regrowth are observed in some treated nodules. The aim of the study was to evaluate the long-term outcomes of laser treatment for solid nodules during a 5-year follow-up period, the regrowth rate, and the predictive risk factors of nodule regrowth.

Materials and Methods

We retrospectively evaluated patients with benign, solid, cold thyroid nodules who underwent laser ablation and were followed-up for 5 years. According to the selection criteria, 104 patients were included (median baseline nodule volume, 12.5 mL [25.0–75.0%, 8–18 mL]; median energy delivered, 481.5 J/mL [25.0–75.0%, 370–620 J/mL]). Nodule volume, thyroid function test results, and ultrasound were evaluated at baseline and then annually after the procedure.

Results

Of 104 patients, 31 patients (29.8%) had a 12-month volume reduction ratio (VRR) < 50.0% and 39 (37.5%) experienced nodule regrowth. Of these 39 patients, 17 (43.6%) underwent surgery and 14 (35.9%) underwent a second laser treatment. The rate of nodule regrowth was inversely related to the 12-month VRR, i.e., the lower the 12-month VRR, the higher the risk of regrowth (p < 0.001). The mean time for nodule regrowth was 33.5 ± 16.6 months. The 12-month VRR was directly related to time to regrowth, i.e., the lower the 12-month VRR, the shorter the time to regrowth (p < 0.001; R² = 0.3516). Non-spongiform composition increased the risk of regrowth with an odds ratio of 4.3 (95% confidence interval [CI] 1.8–10.2; p < 0.001); 12-month VRR < 50.0% increased the risk of regrowth with an odds ratio of 11.7 (95% CI 4.2–32.2; p < 0.001).

Conclusion

The VRR of thyroid nodules subjected to similar amounts of laser energy varies widely and depends on the nodule composition; non-spongiform nodules are reduced to a lesser extent and regrow more frequently than spongiform nodules. A 12-month VRR < 50.0% is a predictive risk factor for regrowth and correlates with the time to regrowth.

Long-term follow-up of cystic thyroid nodules treated with percutaneous ethanol injection (PEI) using two different approaches

BACKGROUND AND AIM

Cystic thyroid nodules (CNs), although generally benign, can cause compressive or aesthetic problems. Percutaneous ethanol injection (PEI) can represent an alternative to surgery. The present retrospective study evaluates: (i) the long-term outcome of CNs after PEI; (ii) the differences between two different PEI protocols; (iii) the CNs response according to the liquid component.

MATERIALS AND METHODS

The study comprises 358 nodules post-PEI followed for at least 2 years. PEI was performed according to two different treatment protocols with a single (Foggia) or double (Turin) alcohol injection. CNs were divided according to their composition: cystic (CYS) >90%, mainly cystic (M-CYS) 75-90%, mixed (MIX) 50-75%, solid-mixed (S-MIX) 35-50%. The volume reduction rate (VRR) was defined as nodule volume (mL) after PEI/nodule volume (mL) before PEI x 100.

RESULTS

The 1-year VRR was significantly higher than that at 6 months (89.5% vs 72.9%, P = 0.0005), no differences were observed after 1 year. A significant difference between Turin and Foggia was observed only in VRR at early visit (79% vs 86%, respectively, P = 0.002) and recurrence rate (14% vs 24%, respectively, P = 0.001). Minor side-effects were infrequent. In 192 nodules with a 10-year follow-up CYS showed higher VRR than MIX and S-MIX nodules (P < 0.001).

CONCLUSION

Our study reported that the long-term outcome of CNs treated with PEI is excellent regardless of the PEI technique utilized; the larger the cystic amount, the higher the VRR. Based on present results, PEI can be considered as the first-line choice for treating thyroid CNs.

Treating thyroid nodules by radiofrequency: is the delivered energy correlated with the volume reduction rate? A pilot study

OBJECTIVE

Radiofrequency ablation (RFA) was proven as effective in reducing thyroid nodules' volume. However, whether technical procedure aspects could influence the volume reduction rate (VRR) has not been clarified. This retrospective pilot study aimed to analyze the correlation of RFA power, duration, and energy with VRR.

METHODS

During the period from June to December 2018 two primary-care centers treated benign thyroid nodules of adult outpatients according to the same RFA procedure. Technical parameters to be investigated were the following: median power (P_median), effective time of treatment (T_eff), energy calculated as P_median × T_eff (E_calc), and energy delivered per mL as Kcal × 4184 × nodule's volume (E_del). Continuous variables were analyzed by the Mann-Whitney test. Data of 1-year posttreatment follow-up were collected on December 2019 and the correlation of the above parameters with VRR was analyzed by linear regression.

RESULTS

Forty-one nodules were included and their 1-year VRR was 66.6%. RFA was performed with a P_median of 55 W, T_eff 10.24 min, E_calc 31,380 J, and E_del 1473 J/mL. E_del was significantly correlated with VRR (p = 0.014) while P_median, T_eff, and E_calc not. A strong correlation of E_del with VRR was found in nodules <10 mL (p = 0.001) while no significant correlation was observed in nodules >10 mL.

CONCLUSIONS

This study showed that the energy delivered with RFA is the only technical parameter significantly correlated with the VRR of thyroid nodules.

Performance of EU-TIRADS in malignancy risk stratification of thyroid nodules: a meta-analysis

OBJECTIVE

Several thyroid imaging reporting and data systems (TIRADS) have been proposed to stratify the malignancy risk of thyroid nodule by ultrasound. The TIRADS by the European Thyroid Association, namely EU-TIRADS, was the last one to be published.

DESIGN

We conducted a meta-analysis to assess the prevalence of malignancy in each EU-TIRADS class and the performance of EU-TIRADS class 5 vs 2, 3 and 4 in detecting malignant lesions.

METHODS

Four databases were searched until December 2019. Original articles reporting the performance of EU-TIRADS and adopting histology as reference standard were included. The number of malignant nodules in each class and the number of nodules classified as true/false positive/negative were extracted. A random-effects model was used for pooling data.

RESULTS

Seven studies were included, evaluating 5672 thyroid nodules. The prevalence of malignancy in each EU-TIRADS class was 0.5% (95% CI: 0.0-1.3), 5.9% (95% CI: 2.6-9.2), 21.4% (95% CI: 11.1-31.7), and 76.1% (95% CI: 63.7-88.5). Sensitivity, specificity, PPV, NPV, LR+, LR- and DOR of EU-TIRADS class 5 were 83.5% (95% CI: 74.5-89.8), 84.3% (95% CI: 66.2-93.7), 76.1% (95% CI: 63.7-88.5), 85.4% (95% CI: 79.1-91.8), 4.9 (95% CI: 2.9-8.2), 0.2 (95% CI: 0.1-0.3), and 24.5 (95% CI: 11.7-51.0), respectively. A further improved performance was found after excluding two studies because of limited sample size and low prevalence of malignancy in class 5.

CONCLUSIONS

A limited number of studies generally conducted using a retrospective design was found. Acknowledging this limitation, the performance of EU-TIRADS in stratifying the risk of thyroid nodules was high. Also, EU-TIRADS class 5 showed moderate evidence of detecting malignant lesions.

Is concomitant treatment with steroids and radiotherapy more favorable than sequential treatment in moderate-to-severe graves orbitopathy?

PURPOSE

Glucocorticoids (GCs) and external radiotherapy (RT) are used for treating moderate-to-severe Graves' orbitopathy (GO). We aimed to assess whether GCs and RT were more effective when administered concomitantly or sequentially.

METHODS

We retrospectively analyzed clinical outcomes [assessed by Clinical Activity Score (CAS) and NOSPECS classification] in 73 patients treated with both i.v. GCs and RT. The patients were divided in two groups: In group A (53 patients), RT was delivered concomitantly with GCs, and in group B (20 patients) RT was administered subsequently to the end of methylprednisolone.

RESULTS

At baseline, CAS (median 4.0) and the percentage of patients encompassing the various grades of the classes 2, 3 and 4 of the NOSPECS score were similar in both groups. Six months after RT, CAS decreased to 2 in both groups (p = 0.0003 vs baseline) as well as NOSPECS class 4 (p < 0.0001 vs baseline). NOSPECS class 2 improved more in group A than in group B (p = 0.016). The median cumulative dose of GCs was lower in group A than in group B (median 4.500 vs 6000 mg, p < 0.007); the overall length of therapy was shorter in group A than in group B (68 vs 106 days, p < 0,02). The most common acute adverse effect was transient conjunctivitis (five in group A and three in group B); seven patients (five in group A and two in group B, age between 60 and 66 years) developed cataract, requiring surgery in five cases.

CONCLUSIONS

Concomitant administration of GC and RT showed a favorable effect in moderate-to-severe GO, thus suggesting that RT should be carried out early during steroid therapy, when clinical symptoms do not improve or deteriorate after the first i.v. administrations of GCs.

Machine Learning Prediction of Radiofrequency Thermal Ablation Efficacy: A New Option to Optimize Thyroid Nodule Selection

BACKGROUND

Radiofrequency (RF) is a therapeutic modality for reducing the volume of large benign thyroid nodules. If thermal therapies are interpreted as an alternative strategy to surgery, critical issues in their use are represented by the extent of nodule reduction and by the durability of nodule reduction over a long period of time.

OBJECTIVE

To assess the ability of machine learning to discriminate nodules with volume reduction rate (VRR) < or ≥50% at 12 months following RF treatment.

METHODS

A machine learning model was trained with a dataset of 402 cytologically benign thyroid nodules subjected to RF at six Italian Institutions. The model was trained with the following variables: baseline nodule volume, echostructure, macrocalcalcifications, vascularity, and 12-month VRR.

RESULTS

After training, the model could distinguish between nodules having VRR <50% from those having VRR ≥50% in 85% of cases (accuracy: 0.85; 95% confidence interval [CI]: 0.80-0.90; sensitivity: 0.70; 95% CI: 0.62-0.75; specificity: 0.99; 95% CI: 0.98-1.0; positive predictive value: 0.95; 95% CI: 0.92-0.98; negative predictive value: 0.95; 95% CI: 0.92-0.98).

CONCLUSIONS

This study demonstrates that a machine learning model can reliably identify those nodules that will have VRR < or ≥50% at 12 months after one RF treatment session. Predicting which nodules will be poor or good responders represents valuable data that may help physicians and patients decide on the best treatment option between thermal ablation and surgery or in predicting if more than one session might be necessary to obtain a significant volume reduction.

Prognosis of patients with differentiated thyroid carcinomas having a preoperative cytological report of indeterminate at low or high risk. A multicenter study

BACKGROUND

Italian cytology system for thyroid fine-needle aspiration (FNA) includes indeterminate lesions at low- (Tir 3A) and high-risk (Tir 3B). The present retrospective multicenter study was undertaken to compare the histological type of cancers and disease-free survival in these two groups.

METHODS

Eight institutions participated. Thyroid cancer patients diagnosed and followed-up after Tir 3A or Tir 3B were reviewed. Histological diagnosis was adopted as the gold standard. Patients were defined with cancer recurrence or no evidence of disease. Disease-free survival (DFS) was calculated. A non-parametric statistical analysis was used. DFS was estimated by Kaplan-Meier method and Hazard Ratio (HR) defined the slope of curves.

RESULTS

Two hundred and nine patients (median DFS 24 months) were enrolled and a 6.3% of these recurred. Tir 3B group had higher age (p = 0.014), larger cancer size (p = 0.0002), shorter DFS (p = 0.003), higher number of aggressive cancers (p = 0.006), and relapse frequency double than Tir 3A. At survival curves analysis, Tir 3B group had HR of 2.37 with respect to Tir 3A. At Cox's proportional hazard regression analysis histology was the only significant predictor of relapse.

CONCLUSIONS

While patients with thyroid FNA of Tir 3B should be addressed to surgery due to high likelihood of more aggressive cancer, a diagnostic surgery could be avoided in patients with Tir 3A if concurrent unsuspicious clinical features are found.

Long-Term Efficacy of a Single Session of RFA for Benign Thyroid Nodules: A Longitudinal 5-Year Observational Study

CONTEXT

Radiofrequency ablation (RFA) of benign thyroid nodules has been gaining consensus. However, no solid information on its long-term efficacy is available.

OBJECTIVE

To analyze the long-term results of single-session RFA.

DESIGN

Retrospective longitudinal observational study.

SETTING

Primary care center.

PATIENTS OR OTHER PARTICIPANTS

Adult outpatients who underwent a single-session RFA and posttreatment follow-up of least 3 years.

INTERVENTION

Ultrasound-guided RFA was performed after local anesthesia by "moving-shot" technique. RFA was performed with a median power of 55W and a median time of 14 minutes with an internally cooled 18-gauge electrode with an active 10-mm tip.

MAIN OUTCOME MEASURES

Objective (trend of nodule volume) and subjective (compressive and cosmetic concerns) response to RFA were evaluated. Continuous variables were analyzed by the Wilcoxon and ANOVA test and their correlations by using the Spearman test. Categorical variables were compared by Pearson χ2 test.

RESULTS

Two hundred and fifteen patients were included. An early significant reduction of nodule volume was found at 1 year, lasting up to 5 years. A 67% nodule shrinkage was observed at the end of the observation period. The best response was recorded in nodules below 10 mL (79% reduction early and 81% at 5 years). Patients' symptoms were significantly reduced.

CONCLUSIONS

This study, by demonstrating a durable shrinkage of benign thyroid nodules treated by RFA with an improvement of subjective symptoms, establishes the reliability of RFA as alternative to surgery in the management of thyroid nodules, thus representing a remarkable novelty for clinical practice.

Minimally-invasive treatments for benign thyroid nodules: a Delphi-based consensus statement from the Italian minimally-invasive treatments of the thyroid (MITT) group

Benign thyroid nodules are a common clinical occurrence and usually do not require treatment unless symptomatic. During the last years, ultrasound-guided minimally invasive treatments (MIT) gained an increasing role in the management of nodules causing local symptoms. In February 2018, the Italian MIT Thyroid Group was founded to create a permanent cooperation between Italian and international physicians dedicated to clinical research and assistance on MIT for thyroid nodules. The group drafted this list of statements based on literature review and consensus opinion of interdisciplinary experts to facilitate the diffusion and the appropriate use of MIT of thyroid nodules in clinical practice. (#1) Predominantly cystic/cystic symptomatic nodules should first undergo US-guided aspiration; ethanol injection should be performed if relapsing (level of evidence [LoE]: ethanol is superior to simple aspiration = 2); (#2) In symptomatic cystic nodules, thermal ablation is an option when symptoms persist after ethanol ablation (LoE = 4); (#3) Double cytological benignity confirmation is needed before thermal ablation (LoE = 2); (#4) Single cytological sample is adequate in ultrasound low risk (EU-TIRADS ≤3) and in autonomously functioning nodules (LoE = 2); (#5) Thermal ablation may be proposed as first-line treatment for solid, symptomatic, nonfunctioning, benign nodules (LoE = 2); (#6) Thermal ablation may be used for dominant lesions in nonfunctioning multinodular goiter in patients refusing/not eligible for surgery (LoE = 5); (#7) Clinical and ultrasound follow-up is appropriate after thermal ablation (LoE = 2); (#8) Nodule re-treatment can be considered when symptoms relapse or partially resolve (LoE = 2); (#9) In case of nodule regrowth, a new cytological assessment is suggested before second ablation (LoE = 5); (#10) Thermal ablation is an option for autonomously functioning nodules in patients refusing/not eligible for radioiodine or surgery (LoE = 2); (#11) Small autonomously functioning nodules can be treated with thermal ablation when thyroid tissue sparing is a priority and ≥80% nodule volume ablation is expected (LoE = 3).

Radiofrequency ablation for benign thyroid nodules according to different ultrasound features: an Italian multicentre prospective study

Background The purpose of this study was to confirm the generalisation of radiofrequency ablation (RFA) in the treatment of benign thyroid nodules (BTN) and to look for a correlation between final shrinkage and some ultrasound (US) findings in a large Italian population data set. Methods This prospective study included 337 patients with solid cold BTN from six Italian institutions. Nodule volume, US pattern, thyroid function, symptom/cosmetic scores and complications were evaluated before treatment and at 6 and 12 months. The primary outcome was to find a correlation between basal volume and US pattern of the nodules and final shrinkage. The secondary outcome was to confirm the efficacy and safety of RFA in a large data set. Results The median basal volume was 20.7 mL, and this significantly decreased after RFA at 6 months (7.3 mL (-63.5%), P < 0.001) and at 12 months (6 mL (-70%), P vs 6 months = 0.009). A significant correlation was found for US structure (a spongiform pattern showing a 76% reduction vs 67 and 66% of mix and solid patterns respectively, P < 0.01) as well as for vascularity (intense peripheral and intranodal patterns showing 71 vs 68 and 67% of weak peripheral and intranodal and peripheral patterns respectively, P < 0.03), but not for macrocalcifications. A slight inverse correlation was found between nodule basal volume and shrinkage (Spearman: -0.23). Mean symptoms/cosmetic scores were significantly reduced. No major complications were encountered. Conclusions This multicentre study validated the efficacy and safety of RFA for treating BTN and showed a clear correlation between final shrinkage and some common US findings.

Quantitative analysis of thyroid tumors vascularity: A comparison between 3-D contrast-enhanced ultrasound and 3-D Power Doppler on benign and malignant thyroid nodules

PURPOSE

To perform a comparative quantitative analysis of Power Doppler ultrasound (PDUS) and Contrast-Enhancement ultrasound (CEUS) for the quantification of thyroid nodules vascularity patterns, with the goal of identifying biomarkers correlated with the malignancy of the nodule with both imaging techniques.

METHODS

We propose a novel method to reconstruct the vascular architecture from 3-D PDUS and CEUS images of thyroid nodules, and to automatically extract seven quantitative features related to the morphology and distribution of vascular network. Features include three tortuosity metrics, the number of vascular trees and branches, the vascular volume density, and the main spatial vascularity pattern. Feature extraction was performed on 20 thyroid lesions (ten benign and ten malignant), of which we acquired both PDUS and CEUS. MANOVA (multivariate analysis of variance) was used to differentiate benign and malignant lesions based on the most significant features.

RESULTS

The analysis of the extracted features showed a significant difference between the benign and malignant nodules for both PDUS and CEUS techniques for all the features. Furthermore, by using a linear classifier on the significant features identified by the MANOVA, benign nodules could be entirely separated from the malignant ones.

CONCLUSIONS

Our early results confirm the correlation between the morphology and distribution of blood vessels and the malignancy of the lesion, and also show (at least for the dataset used in this study) a considerable similarity in terms of findings of PDUS and CEUS imaging for thyroid nodules diagnosis and classification.

American Thyroid Association ultrasound system for the initial assessment of thyroid nodules: Use in stratifying the risk of malignancy of indeterminate lesions

BACKGROUND

The ultrasound risk stratification system of the American Thyroid Association (ATA) is frequently adopted in clinical practice. Here, we evaluated its performance in a series of nodules with indeterminate fine-needle aspiration cytology (FNAC) report.

METHODS

Indeterminate thyroid nodules diagnosed at 2 medical centers were retrospectively screened, ultrasound images were reevaluated, and lesions were classified according to the ATA. Single ultrasound parameters were also analyzed.

RESULTS

One hundred seventy-three indeterminate lesions were included with 24.8% of malignancy. The high suspicion class showed a cancer rate (75%) significantly (P < .001) higher than that recorded in the other categories (16.8%). Between ultrasound parameters, halo and microcalcifications were the most sensitive and specific ones. The most accurate receiver operating characteristic (ROC)-derived cutoff of nodule's diameter was >4.1 cm. At multivariate analysis, only the ATA class of high suspicion and size >4.1 cm were significantly associated with cancer (odds ratios [ORs] 19.4 and 5.4, respectively).

CONCLUSION

The ATA ultrasound system is reliable in the risk stratification of indeterminate thyroid lesions.

A comparison of laser with radiofrequency ablation for the treatment of benign thyroid nodules: a propensity score matching analysis

PURPOSE

To compare technique efficacy and safety of laser ablation (LA) and radiofrequency ablation (RFA) in treatment of benign thyroid nodules.

MATERIALS AND METHODS

Institutional review board approval was obtained, and patients' consent was waived. 601 nodules were treated from May 2009 to December 2014 at eight centres, 449 (309 females, age 57 ± 14 years) with LA and 152 (107 females, age 57 ± 14 years) with RFA. A matched cohort composed of 138 patients from each group was selected after adjustment with propensity score matching. Factors influencing volume reduction at 6 and 12 months and complications were evaluated.

RESULTS

No significant differences were observed in the baseline characteristics between groups after propensity score matching adjustment. Mean nodule reduction at 6 and 12 months was -67 ± 19% vs. -57 ± 21% (p < 0.001) - 70 ± 19% vs. -62 ± 22% (p = 0.001) in LA group and in RFA group, respectively. Nodules with volume >30 mL had significantly higher percentage volume reduction at 6 and 12 months (-69 ± 19 vs. -50 ± 21, p = 0.001) and (-73 ± 18 vs. -54 ± 23 8, p = 0.001) in the LA group than in the RFA group, respectively. In both groups, operator's skills affected the results. Major complications occurred in 4 cases in each group (p = 0.116) Conclusions: LA and RFA showed nearly similar outcome but LA was slightly more effective than RFA in large nodules. Operator's skills could be crucial in determining the extent of nodule volume reduction regardless of the used technique.

Efficacy and Safety of Radiofrequency Ablation Versus Observation for Nonfunctioning Benign Thyroid Nodules: A Randomized Controlled International Collaborative Trial

BACKGROUND

Percutaneous radiofrequency thermal ablation (RFA) has been reported as an effective tool for the management of benign thyroid nodules (BTN). However, large, randomized controlled trials (RCTs) are lacking.

OBJECTIVE

The aims of this study were to assess the volume reduction of BTN after a single RFA performed using the moving-shot technique and to compare the volume reduction obtained in patients treated in two centers with different experience of the moving-shot technique.

METHOD

This study was an international prospective RCT. It was carried out at the Mauriziano Hospital (Turin, Italy) and the Asan Medical Center (Seoul, Korea). Eighty patients harboring solid, compressive, nonfunctioning BTN (volume 10-20 mL) were enrolled. Twenty patients in each country were treated by RFA using a 18-Gauge internally cooled electrode (group A); 20 nontreated patients in each country were followed as controls (group B).

RESULTS

At six months, BTN volume significantly decreased in group A (15.1±3.1 mL vs. 4.2±2.7 mL; p<0.0001), whereas it remained unchanged in group B (14.4±3.3 mL vs. 15.2±3.5 mL). The baseline volume was larger in the Italian series (16.4±2.5 mL vs. 13.9±3.3 mL, p=0.009). However, at six months, there was no significant difference between the Korean group and the Italian group (3.7±2.9 mL vs. 5.5±2.2 mL). Both cosmetic and compressive symptoms significantly improved (3.6±0.5 vs. 1.7±0.4 and 3.6±1.9 vs. 0.4±0.7, respectively; p<0.001). No side effects occurred.

CONCLUSIONS

RFA was effective in reducing the volume of BTN. The outcome was similar in centers with different experience in the moving-shot technique.

Diagnostic performance of elastography in cytologically indeterminate thyroid nodules

Cytological examination of material from fine-needle aspiration biopsy is the mainstay of diagnosis of thyroid nodules, thanks to its remarkable accuracy and scarcity of complications. However, follicular lesions (also called indeterminate lesions or Thy3 in the current classification), a heterogeneous group of lesions in which cytology is unable to give a definitive diagnosis to, represent its main limit. Elastography has been proposed as a potential diagnostic tool to define the risk of malignancy in the aforementioned nodules, but at present there is no conclusive data due to the small number of specifically addressed studies and the lack of concordance among them. The objective of our study was to evaluate the role of real-time elastography (RTE) for refining diagnosis of Thy3 nodules, by integrating diagnostic information provided by traditional ultrasound (US). The study included 108 patients with Thy3 nodules awaiting for surgery, which were evaluated by US (considering hypoecogenicity, irregular margins, microcalcifications, halo sign, and intranodular vascularization) and RTE. Nodules were classified at RTE using a four-class color scale. At histologic examination, 75 nodules were benign and 33 malignant. As expected, none of the ultrasound parameters alone was adequate in predicting malignancy or benignity of the nodules; in the presence of at least two US risk factors, we obtained 61 % sensitivity, 83 % specificity, and 77 % accuracy with 6.8 OR (95 % CI 2.4-20.4). RTE scores 3 and 4 showed 76 % sensitivity, 88 % specificity, 74 % PPV, and 89 % NPV with diagnostic accuracy of 84 %; the data are statistically significant (p < 0.0001) with a OR of 21.9 (95 % CI 7.1-76). By combining RTE with US parameters, the presence of at least 2 characters of suspicion had 88 % sensitivity and 94 % NPV with 23.8 OR (95 % CI 7-106.3). The use of combined RTE and US leads to the identification of two patients subpopulations which have a significantly different malignancy risk (6 vs. 63 %); further studies are needed to verify if it is possible to send only the first group to thyroidectomy and the other to follow-up.

BRAF (V600E) associates with cytoplasmatic localization of p27kip1 and higher cytokeratin 19 expression in papillary thyroid carcinoma

The genetic alterations are responsible for the altered protein expression in tumors. The knowledge of the link between the altered protein expression and genetic alterations may provide potentially important biological and clinical information. In this study, the expression of some protein markers (Gal-3, p21Kip1, CK19) known to be associated to the papillary thyroid carcinoma (PTC) was assessed in a series of surgical samples by immunohistochemistry, and the association between expression of these markers and the BRAF (V600E) mutation was investigated. Gal-3 positive staining was evident in 26 % of benign nodules. The BRAF (V600E) mutation and Gal-3 expression, were found in 55.5 and 87 % of PTC respectively, and were unlinked. The expression of CK19 in benign nodules was weak and limited to scattered follicular cells. Diffuse cytoplasmatic expression of CK19 was present in malignant tumors in a variable percentage of cells. A higher percentage of CK19 expressing cells was associated with BRAF (V600E) (P ≤ 0.001). All benign nodules displayed nuclear p27kip1 in more than 15 % of the cells. Twenty-nine PTC showed a cytoplasmatic staining with negative nuclei. PTC with cytoplasmatic or 0-5 % of cells with nuclear staining, 6-15 % or >15 % of cells with nuclear staining were 72 (66.7 %), 24 (22.2 %), and 12 (11.1 %) respectively. In BRAF (V600E) positive tumors, the cytoplasmatic localization of p27kip1 was significantly more frequent (P = 0.024). In conclusion, we provide evidences that BRAF (V600E) is non-associated with Gal-3 expression, whereas it is associated with cytoplasmatic localization of p27kip1 and higher CK19 expression in PTC.

High diagnostic accuracy and interobserver reliability of real-time elastography in the evaluation of thyroid nodules

Elastography is a new diagnostic tool in the evaluation of thyroid nodules. Aim of the study was to evaluate the accuracy and reliability of elastography in discriminating thyroid lesions and the interobserver variability. One hundred thirty-two nodules in 115 patients selected for thyroid surgery underwent conventional ultrasound and elastographic evaluation. Elastography score was divided in four categories (totally elastic nodule, mainly elastic, mainly rigid and totally rigid) according to signal distribution. Three independent operators conducted the study. Final histology showed 92 benign nodules and 40 malignant. On elastography, 77/92 benign nodules were classified as score 1 or 2 and 34/40 malignant nodules as score 3 or 4 (sensitivity 85%, specificity 83.7%, positive predictive value [PPV] 69.3%, negative predictive value [NPV] 92.7%). Rate of concordance between operators was good (K test: 0.64, p < 0.0001). Simple to use, with good interobserver agreement, elastography has all the requisites to become an important complement of conventional US examination in the near future.

High growth rate of benign thyroid nodules bearing RET/PTC rearrangements

CONTEXT

Benign thyroid nodules display a broad range of behaviors from a stationary size to a progressive growth. The RET/PTC oncogene has been documented in a fraction of benign thyroid nodules, besides papillary thyroid carcinomas, and it might therefore influence their growth.

OBJECTIVE

The aim of the present work was to evaluate whether RET/PTC in benign thyroid nodules associates with a different nodular growth rate.

STUDY DESIGN

In this prospective multicentric study, 125 subjects with benign nodules were included. RET rearrangements were analyzed in cytology samples; clinical and ultrasonographic nodule characteristics were assessed at the start and at the end of the study.

RESULTS

RET/PTC was present in 19 nodules. The difference between the mean baseline nodular volume of the RET/PTC- and RET/PTC+ nodules was not significant. After 36 months of follow-up, the RET/PTC+ group (n = 16) reached a volume higher than the RET/PTC- group (n = 90) (5.04 ± 2.67 vs. 3.04 ± 2.26 ml; P = 0.0028). We calculated the monthly change of nodule volumes as a percentage of baseline. After a mean follow-up of 36.6 months, the monthly volume increase of nodules bearing a RET rearrangement was 4.3-fold that of nodules with wild-type RET (1.83 ± 1.2 vs. 0.43 ± 1.0% of baseline volume; P < 0.0001).

CONCLUSIONS

Benign thyroid nodules bearing RET rearrangements grow more rapidly than those with wild-type RET. Searching for RET rearrangements in benign thyroid nodules might be useful to the clinician in choosing the more appropriate and timely therapeutic option.

Prevalence of RET/PTC rearrangement in benign and malignant thyroid nodules and its clinical application

Fine-needle aspiration cytology (FNAC) is the primary means to distinguish benign thyroid nodules from malignant ones. About 20% of FNAC yields indeterminate results leading to unnecessary or delayed surgery. Many studies of tissue samples, the majority of which are retrospective advocate testing for RET rearrangements as a diagnostic adjunctive tool in thyroid nodules with indeterminate cytological findings. Because of the uncertain prevalence of RET rearrangements, its utility as a tumor marker is still controversial. The goal of this study was to establish the prevalence and the utility of testing for RET rearrangements in FNAC suspicious of cancer in a clinical setting. In this prospective study, we analysed a large series of thyroid aspirates by RT-PCR only and Southern blot on RT-PCR products for type 1 and 3 RET rearrangements. Results were compared with clinical findings, cytological diagnosis and final histopathology. By the higher sensitive Southern-blot on RT-PCR method, RET rearrangements were present in 36% of papillary thyroid carcinomas (RET/PTC-1, 12%; RET/PTC-3, 20%; both, 4%) and of 13.3% of benign nodules. By means of RT-PCR only, RET rearrangements were disclosed only in 14.3% of PTC and in 3.6% of benign nodules. No significant correlation was found between RET rearrangements and clinicopathological features of patients. These results indicate that molecular testing of thyroid nodules for RET/PTC must take into account of its high prevalence in benign nodules, inducing false positive diagnoses when the highly sensitive assay Southern-blot on RT-PCR is used. Its searching by means of RT-PCR only, has a specificity superior of conventional cytology and can be used to refine inconclusive FNAC.

Diagnostic value of a cytomorphological subclassification of follicular patterned thyroid lesions: a study of 927 consecutive cases with histological correlation

BACKGROUND

Fine-needle aspiration cytology (FNAC) has proved to be an effective diagnostic tool in patients with thyroid nodules. Several reporting schemes have been suggested to define the risk of malignancy and consequent clinical management. To date, however, among lesions showing a follicular pattern, FNAC is still unable to differentiate between benign and malignant ones. The aim of our study was to evaluate whether a subclassification of follicular cytologic specimens, based on cytoarchitectural patterns, could differentiate categories with a different risk of malignancy, thus improving the clinical management of patients harboring follicular nodules.

METHODS

We report a cohort of 927 consecutive cases who underwent thyroid surgery in our hospital between 2000 and 2008. Each patient underwent FNAC before surgery. All the cytologic specimens were divided into five categories (Thy 1: inadequate material, Thy 2: benign, Thy 3: indeterminate, Thy 4: suspicious for malignancy, Thy 5: malignant). Thy3 specimens were further divided into three subcategories (Thy 3a, or "follicular lesions of indeterminate significance": scant colloid, microfollicular pattern, or small clusters of thyrocytes with round nuclei usually without, but sometimes with, minimal cellular pleomorphism; Thy 3b, or "follicular neoplasm": absence of colloid, small clusters, or microfollicles of medium-large sized cell populations arranged in cohesive groups with nuclear overlapping, crowding, and pleomorphisms; and Thy 3c or "Hurthle-cell neoplasm": scant colloid, sheets or clusters of oxyphilic cells).

RESULTS

Thy 1 specimens (51 cases on the whole) proved to be malignant in 5.88% (3 cases), Thy 2 specimens (319) in 3.45% (11 cases), Thy 4 specimens (91) in 84.62% (77 cases), and Thy 5 specimens (172) in 98.84% (170 cases). Thy 3 specimens (294 cases) proved to be malignant in 17.35% as a whole, but when divided into the three subcategories, the percentage of malignant cases was significantly different between the Thy 3a group (4.95%) and the Thy 3b and Thy 3c groups (25.0% and 22.77% respectively).

CONCLUSIONS

This study supports the National Cancer Institute consensus showing a different risk of malignancy for "follicular lesions of undetermined significance” compared with "follicular neoplasms" and "Hurthle cells neoplasms," which are more suspect for malignancy. This subclassification could improve clinical management of thyroid nodules, helping to better select patients for surgery or follow up.

Characterization of single thyroid nodules by contrast-enhanced 3-D ultrasound

High-resolution ultrasonography (HRUS) has potentialities in differential diagnosis between malignant and benign thyroid lesions, but interpretative pitfalls remain and accuracy is still poor. We developed an image processing technique for characterizing the intra-nodular vascularization of thyroid lesions. Twenty nodules (10 malignant) were analyzed by three-dimensional (3-D) contrast-enhanced ultrasound imaging. The 3-D volumes were preprocessed and skeletonized. Seven vascular parameters were computed on the skeletons: number of vascular trees (NT); vascular density (VD); number of branching nodes (or branching points) (NB); mean vessel radius (MR); 2-D (DM) and 3-D (SOAM) tortuosity; and inflection count metric (ICM). Results showed that the malignant nodules had higher values of NT (83.1 vs. 18.1), VD (00.4 vs. 0.01), NB (1453 vs. 552), DM (51 vs. 18), ICM (19.9 vs. 8.7) and SOAM (26 vs. 11). Quantification of nodular vascularization based on 3-D contrast-enhanced ultrasound and skeletonization could help differential diagnosis of thyroid lesions.

Thyroid nodules and related symptoms are stably controlled two years after radiofrequency thermal ablation

BACKGROUND

Percutaneous radiofrequency thermal ablation (RTA) is a promising new therapeutic approach to manage thyroid nodules (TNs). The aim of this study was to investigate the long-term effectiveness of RTA in inducing shrinkage of TNs as well as in controlling compressive symptoms and thyroid hyperfunction in a large series of elderly subjects with solid or mainly solid benign TNs.

METHODS

Ninety-four elderly patients with cytologically benign compressive TNs were prospectively enrolled in the study; 66 of them had nontoxic goiter and 28 had toxic or pretoxic goiter. RTA was performed by using a RITA StarBurst Talon hook-umbrella needle inserted in every single TN under ultrasonographic real-time guidance. TN volume, TN-related compressive symptoms and thyroid function were evaluated at baseline and 12 to 24 months after RTA.

RESULTS

All TNs significantly decreased in size after RTA. The mean decrease in TN volume 12 months after RTA was from 24.5 +/- 2.1 to 7.5 +/- 1.2 mL (p < 0.001), with a mean percent decrease of 78.6 +/- 2.0%. Two years after RTA, a 79.4 +/- 2.5% decrease of TNs size was observed. Compressive symptoms improved in all patients and completely disappeared in 83 of 94 (88%) patients. Hyperthyroidism resolved in most patients allowing methimazole therapy to be completely withdrawn in 79% of patients with pretoxic and toxic TNs (100% with pretoxic TNs and 53% with toxic TNs). The treatment was well tolerated by all patients. No patient needed hospitalization after RTA and no major complications were observed.

CONCLUSIONS

RTA is an effective and simple procedure for obtaining lasting shrinkage of TNs, controlling compressive symptoms, and treating thyroid hyperfunction. When performed in experienced medical centers, RTA may be a valid alternative to conventional treatments for nontoxic and pretoxic TNs. It is particularly attractive for elderly people for whom surgery and radioiodine therapy are often contraindicated or ineffective.

US-guided percutaneous radiofrequency thermal ablation for the treatment of solid benign hyperfunctioning or compressive thyroid nodules

The aim of the study was to define the effectiveness and safety of ultrasound-guided percutaneous radiofrequency (RF) thermal ablation in the treatment of compressive solid benign thyroid nodules. Thirty-one patients not eligible for surgery or radioiodine (131I) treatment underwent RF ablation for benign nodules; a total of 33 nodules were treated (2 patients had 2 nodules treated in the same session): 10 cold nodules and 23 hyperfunctioning. Fourteen patients complained of compressive symptoms. Nodule volume, thyroid function and compressive symptoms were evaluated before treatment and at 1, 3 and 6 mo. Ultrasound-guided RF ablation was performed using a Starbust RITA needle, with nine expandable prongs; total exposure time was 6 to 10 min at 95 degrees C in one area or more of the nodule. Baseline volume (measured at the time of RF ablation) was 27.7 +/- 21.5 mL (mean +/- SD), but significantly decreased during follow-up: 19.2 +/- 16.2 at 1 mo (-32.7%; p < 0.001), 15.9 +/- 14.1 mL at 3 mo (-46.4 %; p < 0.001) and 14.6 +/- 12.6 mL at 6 mo (-50.7%; p < 0.001). After treatment, all patients with cold nodules remained euthyroid: five patients with hot nodules normalized thyroid function, and the remaining sixteen showed a partial remission of hyperthyroidism. Besides a sensation of heat and mild swelling of the neck, no major complications were observed. Improvement in compressive symptoms was reported by 13 patients, with a reduction on severity scale from 6.1 +/- 1.4 to 2.2 +/- 1.9 (p < 0.0001). Radiofrequency was effective and safe in reducing volume by about 50% and compressive symptoms in large benign nodules. Hyperfunction was fully controlled in 24% of patients and partially reduced in the others.

Characterization of thyroid nodules by 3-D contrast-enhanced ultrasound imaging

High resolution ultrasound imaging proved effective in the detection, analysis, and follow-up of thyroid lesions, even if interpretative pitfalls remain. Differentiation between malignant and benign nodules is a major challenge: malignancy is often correlated to an increase in intranodular vasculature, due to rapid angiogenesis. We developed a three-step methodology to reconstruct intranodular vasculature based on 3-D contrast-enhanced images: i) preprocessing; ii) morphological opening by using a structuring element coherent with the microbubbles appearance: iii) thresholding and 3-D representation. We processed the volumes relative to 8 nodules (4 benign and 4 malignant, confirmed by needle biopsy) and we calculated the percentage of intranodular contrast agent. Results confirm that malignant nodules present a higher internal vasculature (52.3% +/- 15.7%) than benign (14.3% +/- 5.3%). Also, two experts reported the reconstructed 3-D volumes and scored the nodules characteristics, obtaining a good agreement with bioptic results. We believe this methodology could be useful to improve nodules differentiation in thyroid ultrasound exams.

Combined analysis of galectin-3 and BRAFV600E improves the accuracy of fine-needle aspiration biopsy with cytological findings suspicious for papillary thyroid carcinoma

Ten to fifteen percent of fine-needle aspiration biopsy (FNAB) of thyroid nodules are indeterminate. Galectin-3 (Gal-3) and the oncogene BRAFV600E are markers of malignancy useful to improve FNAB accuracy. The objective of this study was to determine whether the combined analysis of Gal-3 and BRAFV600E expression in thyroid aspirates could improve the diagnosis in FNAB with suspicious cytological findings. Two hundred and sixty-one surgical thyroid tissues and one hundred and forty-four thyroid aspirates were analyzed for the presence of the two markers. In surgical specimens, Gal-3 expression was present in 27.4% benign nodules, 91.9% papillary (PTC) and 75% follicular (FTC) thyroid carcinomas. BRAFV600E was not detected in 127 benign nodules, as well as in 32 FTCs, while was found in 42.9% PTC. No correlation was found between BRAF mutation and Gal-3 expression. Forty-seven consecutive FNAB suspicious for PTC were analyzed for the presence of the two markers. Of these nodules, 23 were benign at histology, 6 were positive for Gal-3, none displayed BRAFV600E, and 17 were negative for both the markers. Twenty suspicious nodules were diagnosed as PTC and four FTCs at histology. Of these 24 carcinomas, 9 resulted positive for BRAFV600E, 17 for Gal-3, and 22 for one or both the markers. The sensitivity, specificity, and accuracy for the presence of Gal-3 and/or BRAFV600E were significantly higher than those obtained for the two markers alone. Notably, the negative predictive value increased from 70.8 to 89.5%. In conclusion, the combined detection of Gal-3 and BRAFV600E improves the diagnosis in FNAB with cytological findings suspicious for PTC and finds clinical application in selected cases.

Detection of RET/PTC, TRK and BRAF mutations in preoperative diagnosis of thyroid nodules with indeterminate cytological findings

BACKGROUND

Fine-needle aspiration biopsy (FNAB) is the primary means to distinguish benign from malignant nodules and select patients for surgery. However, adjunctive diagnostic tests are needed because in 20-40% of cases the FNAB result is uncertain.

OBJECTIVE

We investigated whether a search for the oncogenes RET/PTC, TRK and BRAF(V600E) in thyroid aspirates could refine an uncertain diagnosis.

PATIENTS AND METHODS

A total of 132 thyroid aspirates, including colloid nodules, inadequate samplings, indeterminate and suspicious for malignancy were analysed by reverse transcription polymerase chain reaction (RT-PCR) and mutant allele-specific amplification techniques for the presence of oncogenes.

RESULTS

No oncogenes were detected in 48 colloid nodules, 46 inadequate and 19 indeterminate FNABs, then confirmed to be benign at histology. No oncogenes were detected in one follicular thyroid cancer (FTC) with indeterminate cytology. Five out of six papillary thyroid cancers (83%) with FNAB suspicious for malignancy were correctly diagnosed by the presence of oncogenes. Among these, four (67%) contained the BRAF mutation and one (17%) contained RET/PTC-3. On final analysis, no false-positive results were reported in 131 samples and five out of seven carcinomas (71%) were correctly diagnosed. The finding of oncogenes in FNAB specimens suspicious for malignancy guided the extent of surgical resection, changing the surgery from diagnostic to therapeutic in five cases.

CONCLUSIONS

Detection of RET/PTC, TRK and BRAF(V600E) in FNAB specimens is proposed as a diagnostic adjunctive tool in the evaluation of thyroid nodules with suspicious cytological findings.

Thyroid Cytology and Risk of Thyroid Cancer: Differences Among Indeterminate Specimens

OBJECTIVE

To assess the potential for stratification of indeterminate cytologic findings on fine-needle aspiration (FNA) of thyroid nodules in an effort to improve therapeutic strategies.

METHODS

We attempted to determine the malignant risk associated with various indeterminate FNA cytologic patterns by correlation of specimens with the final histologic diagnosis. For this analysis, we identified 294 computerized medical records of surgically treated thyroid nodules during a 5-year period at our institution with the corresponding FNA cytology reports available.

RESULTS

Of the 294 surgical cases, 162 with a positive or indeterminate cytologic report were selected, reviewed, and classified. Of 52 patients with positive cytologic findings on FNA, 51 (98%) had a final histologic report of a malignant thyroid nodule. Of 110 patients with indeterminate specimens, 30 (27%) had a final histologic diagnosis of thyroid carcinoma. The presence of nuclear atypia was predictive of thyroid carcinoma in 75% of patients, a Hürthle cell cytologic pattern was associated with a malignant thyroid nodule in 33%, and a hypercellular smear was suggestive of malignant involvement in 26% of cases. The lowest rate of malignant potential was associated with cytologic microfollicular and scant colloid alone subtype (6%).

CONCLUSION

The results of this study show that indeterminate thyroid cytologic specimens can be subdivided into groups with different malignant risks. A microfollicular cytologic pattern in the absence of a hypercellular smear or nuclear atypia does not support a recommendation of surgical treatment. A malignant cytologic diagnosis has a high positive predictive value for detection of thyroid cancer.