Malignancy Risk of Thyroid Nodules That Are Not Classifiable by the American Thyroid Association Ultrasound Risk Stratification System: A Systematic Review and Meta-Analysis

Risk Stratification of Thyroid Nodules Diagnosed as Bethesda Category III by Ultrasound, Size, and Cytology

OBJECTIVE

This study aimed to evaluate the performance of an integrated risk stratification system (RSS) based on ultrasound (US) RSSs, nodule size, and cytology subcategory for diagnosing malignancy in thyroid nodules initially identified as Bethesda category III on fine-needle aspiration.

MATERIALS AND METHODS

This retrospective study was conducted at two institutions and included consecutive patients with Bethesda category III nodules, and final diagnoses confirmed by repeat biopsy or surgery. A total of 320 Bethesda category III nodules (≥1 cm) from 309 patients (223 female and 86 male; mean age, 50.9 ± 12.0 years) were included. The malignancy risk of Bethesda category III nodules and predictors of malignancy were assessed according to US RSSs, nodule size, and cytology subcategory. The diagnostic performances of US-size cytology (USC) RSS and US RSS alone for malignancy were compared.

RESULTS

The intermediate or high suspicion US category independently increased the malignancy risk in all US RSSs (P ≤ 0.001). Large nodule size (≥3 cm) independently increased the malignancy risk of low- or intermediate suspicion US category nodules. Additionally, the atypia of undetermined significance cytology subcategory independently increased the malignancy risk of low suspicion US category nodules in most US RSSs. The area under the receiver operating characteristic curve of the USC RSSs was greater than that of the US RSSs alone (P < 0.048). Malignancy was not found in the very low risk category of USC RSS.

CONCLUSION

The diagnostic performance of USC RSS for malignancy was superior to that of US RSS alone in Bethesda category III nodules. Malignancy can be ruled out in the very low-risk category of USC RSS.

Endoscopic thyroidectomy via chest-collarbone approach versus conventional open thyroidectomy: a retrospective comparative study

OBJECTIVE(S)

Endoscopic thyroidectomy, such as axillary, areola and transoral approaches, offer the advantage of a good cosmetic outcome, but it requires a wider dissection field compared to open thyroidectomy. Recently, chest-collarbone approach thyroidectomy has been widely developed in China because of its shorter anatomical route compared to other endoscopic approaches. This study retrospectively evaluated endoscopic thyroidectomy via chest-collarbone approach in patients with thyroid nodules to determine its feasibility.

METHODS

A total of 46 patients with thyroid disease who underwent endoscopic thyroidectomy between January 2022 and December 2022 were enrolled in the study and randomly matched to patients with thyroid disease who underwent open thyroidectomy at the same time based on nodule size and pathology. Postoperative bleeding, hoarseness situation, hospital stay, postoperative drainage volume, laryngeal nerve palsy, hypoparathyroidism and wound infection were assessed in both groups.

RESULTS

Forty-four patients underwent endoscopic thyroidectomy successfully and two patients changed to open thyroidectomy. The amount of postoperative drainage for the endoscopic thyroidectomy group was 102.78 ± 28.04 mL, and which was 71.91 ± 19.20 for open thyroidectomy group (p < 0.001). The postoperative hospital stay for the endoscopic thyroidectomy group was 8.78 ± 2.57 days, and which was 7.22 ± 1.13 for open thyroidectomy group (p < 0.001). There was no significant difference in postoperative bleeding, hoarseness situation, and wound infection between the two groups. Laryngeal nerve palsy, supraclavicular nerve injury and hypoparathyroidism were not observed in any patient during this study.

CONCLUSION

Chest-collarbone endoscopic thyroid surgery is acceptable. This treatment improves in a good cosmetic outcome in patients with thyroid disease. To assess patients with preoperative nodule size and nature of the case is the impact of the success rate, which is particularly important.

Challenges in Risk Stratification of Solid Atypical Mixed Echogenicity Thyroid Nodules

Background: To determine the prevalence and risk of malignancy (ROM) in solid atypical mixed echogenicity thyroid nodules (SAMENs) with sonographic patterns not classifiable by the 2015 American Thyroid Association Ultrasound Risk Stratification System (NC ATA). Methods: We searched our prospectively collected endocrine surgery thyroid nodule (TN) database, with particular attention to those solid nodules that were NC ATA. An algorithm assigned each into one of the five ATA risk groups per the 2015 American Thyroid Association Ultrasound Risk Stratification System (ATA USRSS). TNs that the algorithm could not assign to a risk group were deemed NC ATA and were subsequently analyzed. Additionally, we categorized this group using an algorithm based on the 2017 American College of Radiology Thyroid Imaging Reporting and Data System (ACR-TIRADS). We were specifically interested in the characteristics that resulted in non-classification by the 2015 ATA USRSS and the fine needle aspiration biopsy (FNAB) cytology and surgical pathology results from the group. Results: We evaluated data from 5,040 nodules, of which 1,772 had surgical pathology. There were 150 solid nodules not classified by 2015 ATA USRSS, all of which demonstrated atypical features along with iso-, hetero-, hyper-and mixed echogenicity (solid atypical mixed echogenicity nodules-SAMENs). Sixty of these nodules were excised and sent for surgical pathology, while 90 were followed without surgical excision. Out of the 90 that did not undergo surgery, 82 underwent FNAB with cytologic evaluation. Of our 150 SAMENs, 40 were malignant by surgical histology and six were likely malignant by cytology (total SAMEN ROM without noninvasive follicular thyroid neoplasm with papillary-l ike nuclear features 31%). The most common sonographic pattern present in our SAMEN group consisted of an isoechoic solid component with microcalcifications (28/40-70% of all excised malignant nodules). In our excised malignant SAMENs, 50% demonstrated follicular-patterned neoplastic architecture while 48% displayed papillary architecture. Conclusion: Our study demonstrates that SAMENs with at least one suspicious sonographic feature: including (1) microcalcifications; (2) irregular or other suspicious margins,;opulation, and a higher ROM (31%) than the intermediate-risk group of the 2015 ATA USRSS (10-20%).

Uni- and Multivariate Analyses of Cancer Risk in Cytologically Indeterminate Thyroid Nodules: A Single-Center Experience

Every year in Italy, about 60,000 new cases of nodular thyroid pathology are diagnosed, of which almost 30% are cytologically indeterminate (TIR3A/3B). The risk of malignancy reported in the literature on thyroid nodules ranges from 5% to 15% for TIR3A and from 15% to 30% for TIR3B. It is suspected that these percentages are higher in practice. We performed univariate and multivariate analyses of clinical risk factors. The medical records of 291 patients who underwent surgery for cytologically indeterminate nodular thyroid disease were retrospectively reviewed. Clinical parameters and preoperative serum markers were then compared between the benign nodular thyroid disease and thyroid cancer groups. For each patient, clinical characteristics, comorbidities, neck ultrasonographic features, and histological reports were statistically analyzed using Chi-squared and Fisher's exact tests. A total of 134 malignant neoplasms were found (46%), divided into 55 cases (35%) in the TIR3A group and 79 cases (59%) in the TIR3B group. Statistical analysis was not significant in both populations for both sex and age (TIR3A p-value = 0.5097 and p-value = 0.1430, TIR3B p-value = 0.5191 p-value = 0.3384), while it was statistically significant in patients with TIR3A nodules associated with thyroiditis (p-value = 0.0009). In addition, the patients with TIR3A and 3B nodules were stratified by ultrasound risk for the prediction of malignancy and it was significant (p = 0.0004 and p < 0.0001). In light of these results, it emerges that surgical treatment of nodular thyroid pathology with indeterminate cytology TIR3A should always be considered, and surgery for TIR3B is mandatory.

Management of Thyroid Nodules

Thyroid nodules are common and the prevalence varies between 4 and 7% by palpation and 19-68% by high-resolution USG. Most thyroid nodules are benign, and the malignancy rate varies between 7 and 15% of patients. Thyroid nodules are detected incidentally during clinical examination or, more often, during imaging studies performed for another reason. All detected thyroid nodules should be evaluated clinically. The main test in evaluating thyroid function is thyroid stimulating hormone (TSH). If the serum TSH level is below the normal reference range, a radionuclide thyroid scan should be performed to determine whether the nodule is hyperfunctioning. If the serum TSH level is normal or high, ultrasonography (US) should be performed to evaluate the nodule. US is the most sensitive imaging method in the evaluation of thyroid nodules. Computed tomography (CT) and magnetic resonance imaging are not routinely used in the initial evaluation of thyroid nodules. There are many risk classification systems according to the USG characteristics of thyroid nodules, and the most widely used in clinical practice are the American Thyroid Association guideline and the American College of Radiology Thyroid Imaging Reporting and Data System. Fine needle aspiration biopsy (FNAB) is the gold standard method in the evaluation of nodules with indication according to USG risk class. In the cytological evaluation of FNAB, the Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) is the most frequently applied cytological classification. TBSRTC is a simplified, 6-category reporting system and was updated in 2023. The application of molecular tests to FNAB specimens, especially those diagnosed with Bethesda III and IV, is increasing to reduce the need for diagnostic surgery. Especially in Bethesda III and IV nodules, different methods are applied in the treatment of nodules according to the malignancy risk of each category, these are follow-up, surgical treatment, radioactive iodine treatment, and non-surgical ablation methods.