Thyroid nodules: Does the suspicion for malignancy really justify the increased thyroidectomy rates?

Expression of RASSF1A, DIRAS3, and AKAP9 Genes in Thyroid Lesions: Implications for Differential Diagnosis and Prognosis of Thyroid Carcinomas

Thyroid carcinoma is the primary endocrine malignancy worldwide. The preoperative examination of thyroid tissue lesion is often unclear. Approximately 25% of thyroid cancers cannot be diagnosed definitively without post-surgery histopathological examination. The assessment of diagnostic and differential markers of thyroid cancers is needed to improve preoperative diagnosis and reduce unnecessary treatments. Here, we assessed the expression of RASSF1A, DIRAS3, and AKAP9 genes, and the presence of BRAF V600E point mutation in benign and malignant thyroid lesions in a Polish cohort (120 patients). We have also performed a comparative analysis of gene expression using data obtained from the Gene Expression Omnibus (GEO) database (307 samples). The expression of RASSF1A and DIRAS3 was decreased, whereas AKAP9's was increased in pathologically changed thyroid compared with normal thyroid tissue, and significantly correlated with e.g., histopathological type of lesion papillary thyroid cancer (PTC) vs follicular thyroid cancer (FTC), patient's age, tumour stage, or its encapsulation. The receiver operating characteristic (ROC) analysis for the more aggressive FTC subtype differential marker suggests value in estimating RASSF1A and AKAP9 expression, with their area under curve (AUC), specificity, and sensitivity at 0.743 (95% CI: 0.548-0.938), 82.2%, and 66.7%; for RASSF1A, and 0.848 (95% CI: 0.698-0.998), 54.8%, and 100%, for AKAP9. Our research gives new insight into the basis of the aggressiveness and progression of thyroid cancers, and provides information on potential differential markers that may improve preoperative diagnosis.

Safety and efficacy of thermal ablation (radiofrequency and laser): should we treat all types of thyroid nodules? †

Background: Thermal ablation is a minimally invasive technique that is gradually acknowledged as an effective alternative to surgery to treat thyroid nodules. Two main techniques have been described: radiofrequency (RFA) and laser ablation. Objective: To evaluate the safety and efficacy of the two main techniques (RFA and laser ablation) for the treatment of benign thyroid nodules. Patients: This bicentric retrospective study included 166 consecutive patients, who received clinical, biological and ultrasound evaluations for thyroid nodules, from October 2013 to November 2017. Methods: One of the two techniques was proposed if a nodule was proven to be benign after fine needle aspiration cytology or micro-biopsy. Adverse events and outcomes (symptoms, nodule reduction) were assessed at 6 weeks and 6, 12, and 18 months after treatment. Results: One hundred and eighty-nine nodules (mean size 17.5 ± 16.9 mL, 86.1% palpable) were treated by RFA (n = 108 (57.1%)) or laser ablation (n = 81 (42.9%)) in 166 patients (80.1% women, mean age 51.7 years). Two cases of transient recurrent laryngeal nerve palsy, one hematoma, and two successfully drained abscesses (5/166 = 3%) were observed. Clinical symptoms improved significantly in the two groups (anterior cervical discomfort -83.6%, esthetic complaints -84.9% and dysphagia -86.4%). Nodule volume (mL) decreased significantly (baseline vs. 18 months) from 20.4 ± 18.6 to 5.8 ± 6.6 (-75%) in the RFA, and from 13.6 ± 13.3 to 3.4 ± 4.1 (-83.9%) in the laser ablation groups. Conclusions: Transient but potentially serious adverse events were reported in 3% of patients. A significant volumetric reduction was achieved with both techniques, regardless of nodule's characteristics, at 18 months.

Treatment of solitary thyroid nodules according to size, preoperative fine-needle aspiration cytology and frozen section: a retrospective single centre study

Background: In order to avoid unnecessary thyroidectomies, it is important to predict the nature of thyroid nodules the more accurately possible. The size of the nodule as a predictive factor for malignancy is very controversial. Another point of debate is the accuracy of preoperative fine-needle aspiration cytology (FNAC) and frozen section (FS). The aim of our study is to correlate the nodule size with the final histological diagnosis and to estimate the accuracy of preoperative FNAC and FS. Methods: Retrospective study including 387 operated patients with ultrasound-detected solitary thyroid nodules from 01 January 2001 to 31 December 2013. The following data were collected: patient age and sex, nodule size, FNAC, FS and final histology results. Results: The odds ratio for malignancy within nodules <40 mm was 2.12 (95% CI: 1.104-4.084). The specificity of FNAC was 97.78% and the negative predictive value (NPV) was 97.78% for nodules ≥40 mm and 93.2% and 96.5% for nodules <40 mm, respectively. The observed specificity and NPV of FS ranged from 98% to 100% and from 87.4% to 98%, respectively. When combining FNAC and FS, the specificity and the NPV were 99% and 98%, respectively. Conclusions: The nodule size is not a predictive factor for thyroid cancer and therefore nodules ≥40 mm should not be routinely resected. A lege artis preparation and performance of FNAC along with an expertise on cytological interpretation can considerably diminish false-negative rate. FS can offer additional accuracy on FNAC results and should, therefore, be a part of patient treatment.

Integrative metabonomics as potential method for diagnosis of thyroid malignancy

Thyroid nodules can be classified into benign and malignant tumors. However, distinguishing between these two types of tumors can be challenging in clinics. Since malignant nodules require surgical intervention whereas asymptomatic benign tumors do not, there is an urgent need for new techniques that enable accurate diagnosis of malignant thyroid nodules. Here, we used ¹H NMR spectroscopy coupled with pattern recognition techniques to analyze the metabonomes of thyroid tissues and their extracts from thyroid lesion patients (n = 53) and their adjacent healthy thyroid tissues (n = 46). We also measured fatty acid compositions using GC−FID/MS techniques as complementary information. We demonstrate that thyroid lesion tissues can be clearly distinguishable from healthy tissues, and malignant tumors can also be distinguished from the benign tumors based on the metabolic profiles, both with high sensitivity and specificity. In addition, we show that thyroid lesions are accompanied with disturbances of multiple metabolic pathways, including alterations in energy metabolism (glycolysis, lipid and TCA cycle), promotions in protein turnover, nucleotide biosynthesis as well as phosphatidylcholine biosynthesis. These findings provide essential information on the metabolic features of thyroid lesions and demonstrate that metabonomics technology can be potentially useful in the rapid and accurate preoperative diagnosis of malignant thyroid nodules.

Real-time elastography: a useful tool for predicting malignancy in thyroid nodules with nondiagnostic cytologic findings

OBJECTIVES

The aim of this study was to evaluate the predictive value of sonography and sonographic elastography in thyroid nodules with nondiagnostic cytologic findings.

METHODS

The study included 101 patients (74 female, mean age ± SD, 55 ± 11 years [range, 27-70 years]; and 27 male, mean age, 62 ± 9 years [range, 42-72 years]) who had at least 1 nodule with nondiagnostic cytologic findings at two different fine-needle aspiration cytologic evaluations and with an indication for hemi or total thyroidectomy for clinical suspicion of malignancy, nodule size, or the occurrence of a coexisting nodule with cytologic findings suspicious for malignancy. All of the patients underwent sonography and elastography 2 months after the second fine-needle aspiration and before surgery. The elastogram was matched with an elasticity color scale and classified as follows: score 1, nodules with high elasticity (soft); score 2, nodules with indeterminate elasticity; and score 3, nodules with low elasticity (hard).

RESULTS

A total of 135 nodules (93.7%) were hyperplastic; 15 (9.4%) were papillary carcinomas; and 9 (6.3%) were follicular adenomas. The association of scores 2 and 3 identified 12 of 15 thyroid cancers (sensitivity, 80.0%; specificity, 93.7%; positive predictive value, 57.1%; negative predictive value, 97.8%; and accuracy, 92.4%), whereas the association of conventional sonographic features plus scores 2 and 3 identified all of the cancers (specificity, 70.8%; positive predictive value, 26.3%; negative predictive value, 100%; and accuracy, 73.6%).

CONCLUSIONS

Our data suggest that elastography could be a promising tool in the management of nodules that are nondiagnostic at cytologic evaluation, reducing unnecessary surgery.

Thyroid nodules; interpretation and importance of fine-needle aspiration (FNA) for the clinician - practical considerations

Thyroid nodules are very common lesions. Despite that the great majority is benign, in a significant percentage of them there is an underlying malignancy. Malignant thyroid nodules should be managed surgically, while the more common benign thyroid nodules may be managed conservatively. A systemic and careful diagnostic evaluation is needed to recognize nodules (overtly malignant or with malignant potential), and to avoid unnecessary surgery in a large percentage of patients with benign disease. Fine-needle aspiration (FNA) has a central role in the diagnostic investigation of the patient with thyroid nodules. FNA is a safe, useful, and cost-effective procedure. To increase accuracy, FNA can be performed under ultrasonographic guidance (if needed). Its results may be particularly helpful in determining the indication for surgery. In contrast, the role of FNA in selecting the extent of surgery is limited today. This is due to the fact that during the last decade there is a clear trend toward radical surgical management of thyroid nodular disease (both benign and malignant) by total/near-total thyroidectomy.

Management of Thyroid nodules in adult patients

Thyroid nodule is a common presentation and requires a structured diagnostic approach to ascertain the risk of malignancy and determine appropriate management. This review article highlights the key points in the history and examination which can help with risk stratification. It also discussed the application of fine needle aspiration cytology findings and the British Thyroid Association Guidelines in clinical practice.

Ex vivo and in vivo evaluation of laser-induced thermotherapy for nodular thyroid disease

BACKGROUND AND OBJECTIVE

The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like laser-induced thermotherapy (LITT) are increasingly used to treat tumors of parenchymatous organs and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for LITT of thyroid nodules.

MATERIALS AND METHODS

Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n = 110) and in vivo (n = 10) using an Nd:YAG laser (1,064 nm). Laser energy was applied for 300 seconds in a power range of 10-20 W. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The lesions were longitudinally and transversally measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed.

RESULTS

The maximum inducible lesion volumes were between 0.74 +/- 0.18 cm(3) at a laser power of 10 W and 3.80 +/- 0.41 cm(3) at 20 W. The maximum temperatures after ablation were between 72.9 +/- 2.9 degrees C (10 W) and 112.9 +/- 9.2 degrees C (20 W) at a distance of 5 mm and between 49.5 +/- 2.2 degrees C (10 W) and 73.2 +/- 6.7 degrees C (20 W) at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of NADPH dehydrogenase activity in thermal lesions as a sign of irreversible cell damage.

CONCLUSIONS

This study is the first to demonstrate a dose-response relationship for LITT of thyroid tissue. LITT is suitable for singular thyroid nodules and induces reproducible clinically relevant lesions with irreversible cell damage in an appropriate application time.

Bipolar radiofrequency ablation for nodular thyroid disease--ex vivo and in vivo evaluation of a dose-response relationship

BACKGROUND

The prevalence of thyroid nodules ranges between 2% and 60% depending on the population studied. However, minimally invasive procedures like radiofrequency ablation (rfA) are increasingly used to treat tumors of parenchymatous organs, and seem to be suitable for singular thyroid nodules as well. Their successful clinical application depends on the induction of sufficiently large lesions and a knowledge of the energy parameters required for complete thermal ablation. The aim of this study was to establish a dose-response relationship for rfA of thyroid nodules.

MATERIAL AND METHODS

Thermal lesions were induced in healthy porcine thyroid glands ex vivo (n=110) and in vivo (n=10) using a bipolar radiofrequency system; rf was applied in a power range of 10-20 watts. During the ablation, continuous temperature measurement at a distance of 5 and 10 mm from the applicator was performed. The transversal and axial lesion diameters were measured, and the volume was calculated. Furthermore, enzyme histochemical analysis of the thyroid tissue was performed.

RESULTS

The inducible lesion volumes were between 0.91±0.71 cm(3) at 20W and 2.80±0.85 cm(3) at 14W. The maximum temperatures after rf ablation were between 44.0±9.7°C and 61.6±13.9°C at a distance of 5 mm and between 30.0±8.6°C and 53.5±8.6°C at a distance of 10 mm from the applicator. The histochemical analysis demonstrates a complete loss of nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) dehydrogenase activity in thermal lesions as a sign of irreversible cell damage.

CONCLUSION

This study is the first to demonstrate a dose-response relationship for rfA of thyroid tissue. rfA is suitable for singular thyroid nodules and induces reproducible, clinically relevant lesions with irreversible cell damage in an appropriate application time.

Cell surface and secreted protein profiles of human thyroid cancer cell lines reveal distinct glycoprotein patterns

Cell surface proteins have been shown to be effective therapeutic targets. In addition, shed forms of these proteins and secreted proteins can serve as biomarkers for diseases, including cancer. Thus, identification of cell surface and secreted proteins has been a prime area of interest in the proteomics field. Most cell surface and secreted proteins are known to be glycosylated, and therefore, a proteomics strategy targeting these proteins was applied to obtain proteomic profiles from various thyroid cancer cell lines that represent the range of thyroid cancers of follicular cell origin. In this study, we oxidized the carbohydrates of secreted proteins and those on the cell surface with periodate and isolated them via covalent coupling to hydrazide resin. The glycoproteins obtained were identified from tryptic peptides and N-linked glycopeptides released from the hydrazide resin using two-dimensional liquid chromatography-tandem mass spectrometry in combination with the gas phase fractionation. Thyroid cancer cell lines derived from papillary thyroid cancer (TPC-1), follicular thyroid cancer (FTC-133), Hurthle cell carcinoma (XTC-1), and anaplastic thyroid cancer (ARO and DRO-1) were evaluated. An average of 150 glycoproteins were identified per cell line, of which more than 57% are known cell surface or secreted glycoproteins. The usefulness of the approach for identifying thyroid cancer associated biomarkers was validated by the identification of glycoproteins (e.g., CD44, galectin 3 and metalloproteinase inhibitor 1) that have been found to be useful markers for thyroid cancer. In addition to glycoproteins that are commonly expressed by all of the cell lines, we identified others that are only expressed in the more well-differentiated thyroid cancer cell lines (follicular, Hurthle cell and papillary), or by cell lines derived from undifferentiated tumors that are uniformly fatal forms of thyroid cancer (i.e., anaplastic). On the basis of the results obtained, a set of glycoprotein biomarker candidates for thyroid cancer is proposed.

The Canadian Pediatric Thyroid Nodule Study: an evaluation of current management practices

BACKGROUND/PURPOSE

Thyroid nodules in children often require surgical treatment. We evaluated management practices for these across Canada.

METHODS

Patient records from 9 Canadian pediatric centers of children undergoing surgery for thyroid nodules over a 6-year period were reviewed. Demographics, presenting features, investigations, surgical treatment, pathology, and complications were assessed.

RESULTS

One hundred and forty-one patients were reviewed (75% female), of whom 117 presented with a palpable mass. Ultrasound and/or thyroid scintigraphy was the most commonly used preoperative imaging studies. Fine-needle aspiration cytology correlated with final pathology in 49% of cases. Overall, the rate of malignancy in this series was 43%, with half being papillary carcinoma. Thirty-two of 57 patients undergoing primary total thyroidectomy had a malignancy; 14 of these had positive preoperative fine-needle aspiration cytologies. Twenty of 71 patients undergoing initial hemithyroidectomy +/- isthmusectomy had a malignancy. Seventeen of these went on to completion thyroidectomy and 3 had malignancy in the second specimen. Hypocalcemia and hoarseness occurred in 14 and 4 patients, respectively. Complications were more common after primary total thyroidectomy; none occurred in patients undergoing completion thyroidectomy.

CONCLUSIONS

The incidence of malignancy in pediatric thyroid nodules is high, and the risk of surgical complications significant. With variable management practices across Canada, evidence-based guidelines for diagnosis and surgical treatment may be valuable.