Role of molecular diagnostic markers in the management of indeterminate and suspicious thyroid nodules

Impact of the Italian Society of Anatomic Pathology and Diagnostic Cytology Classification of Thyroid Nodules in the Treatment of Indeterminate Follicular Lesions: Five-Year Results at a Single Center

PURPOSE

Aim of the study was to assess the impact of the Italian Society of Anatomic Pathology and Diagnostic Cytology (SIAPEC) classification of 2014, on the treatment of indeterminate thyroid lesions (TIR3).

METHODS

We retrospectively analyzed patients undergoing thyroid surgery for TIR3 lesions between 2013 and 2018, at the General Surgery Department of Trieste University Hospital. According to the SIAPEC classification, patients were divided into TIR3A and TIR3B groups. All patients treated before 2014 underwent surgical treatment, and surgical specimens were retrospectively classified after revision of fine-needle aspiration cytology. Starting 2014, TIR3A patients were treated only when symptomatic (i.e., coexistent bilateral thyroid goiter or growing TIR3A nodules), whereas TIR3B patients always received surgical treatment. Hemithyroidectomy (HT) was the procedure of choice. Total thyroidectomy (TT) was performed in case of concurrent bilateral goiter, autoimmune thyroid disease, and/or presence of BRAF and/or RAS mutation. Lastly, we analyzed the malignancy rate in the two groups.

RESULTS

29 TIR3A and 90 TIR3B patients were included in the study. HT was performed in 10 TIR3A patients and 37 TIR3B patients, respectively, with need for reoperation in 4 TIR3B (10.8%) patients due to histological findings of follicular thyroid carcinoma >1  cm. The malignancy rates were 17.2% in TIR3A and 31.1% in TIR3B, (p = 0.16). Predictability of malignancy was almost 89% in BRAF mutation and just 47% in RAS mutation.

CONCLUSIONS

The new SIAPEC classification in association with biomolecular markers has improved diagnostic accuracy, patient selection, and clinical management of TIR3 lesions.

RAS Mutations, and RET/PTC and PAX8/PPAR-gamma Chromosomal Rearrangements Are Also Prevalent in Benign Thyroid Lesions: Implications Thereof and A Systematic Review

BACKGROUND

Molecular markers associated with thyroid malignancy are increasingly being used as differential diagnostic tools for thyroid nodules. However, little has been reported recently regarding the prevalence of these markers in benign lesions. The literature was systematically reviewed to examine studies that reported on the prevalence of these markers in benign thyroid lesions.

METHODS

Appropriate studies published between January 1, 2000, and April 30, 2015, and cataloged in PubMed, Embase, Cochrane, Scopus, and Web of Science databases were searched for by combining different keywords for "thyroid tumor" with both general and specific keywords for "molecular marker" by using "AND" as the Boolean operator. All studies meeting criteria that reported the prevalence of RAS mutations, and RET/PTC and PAX8/PPAR-gamma chromosomal rearrangements in benign thyroid lesions were included for study.

RESULTS

A total of 64 articles (including 8162 patients, of whom 42.5% had benign lesions) that met all the study criteria were systematically reviewed and abstracted. Among 35 studies examining RAS mutations, the reported prevalence of RAS mutation in benign lesions ranged from 0% to 48%. In 38 studies examining RET/PTC rearrangements, the prevalence in benign lesions ranged from 0% to 68%. PAX8/PPAR-gamma rearrangements were examined in 27 studies, with the prevalence in benign lesions ranging from 0% to 55%.

CONCLUSION

The presence of these biomarkers and the tremendous variation in reports of their prevalence in benign lesions suggests the need for caution when including these markers in diagnostic decisions. Further understanding of the importance of these markers, as well as newly discovered markers of thyroid malignancy, may be required in order to avoid overtreatment of patients with benign thyroid tumors.

Clinical presentation of patients with a thyroid follicular neoplasm: are there preoperative predictors of malignancy?

BACKGROUND

Studies examining differences in presentation of patients with benign [follicular adenoma (FA)] and malignant follicular thyroid neoplasms [follicular thyroid carcinoma (FTC) or follicular variant papillary thyroid carcinoma (FVPTC)] include only one or two of these subtypes, and none has considered clinical, cytological, and sonographic features together. We therefore examined presenting clinical features of all benign and malignant follicular neoplasm subtypes in an attempt to identify predictors of malignancy.

METHODS

Consecutive patients with a surgically resected follicular thyroid neoplasm at a tertiary hospital from 2005 to 2013 were reviewed. Age, gender, symptoms, history, physical findings, nodule size, sonographic, cytologic, and final pathologic results were recorded. Multivariate logistic regression was used to determine variables that contributed to a diagnosis of malignant follicular neoplasm.

RESULTS

A total of 616 patients (163 males, 453 females) presented with 441 FAs, 17 FTCs, and 158 FVPTCs. On multivariate analysis, male sex [odds ratio (OR) 1.87, p = 0.008], family history of thyroid cancer (OR 5.16, p < 0.001), and history of head and neck radiation (OR 2.01, p = 0.04) were associated with an increased odds of malignancy; age >45 (OR 2.03, p = 0.001), dysphagia (OR 3.48, p = 0.001) or pressure sensation (OR 3.00, p = 003), concomitant hyperthyroidism (OR 4.76, p = 0.01), nodules ≥4 cm (OR 3.68, p < 0.001), and multinodularity on physical examination (OR 1.93, p = 0.004) were associated with an increased odds of a benign lesion.

CONCLUSIONS

Independent clinical predictors exist that might be helpful in preoperative differentiation of benign and malignant follicular neoplasms. A combination of these predictors with both FNA and molecular results may help us to improve the clinical management of patients with follicular thyroid lesions.