Ultrasonography features of medullary thyroid cancer as predictors of its biological behavior

Using preoperative ultrasound vascularity characteristics to estimate medullary thyroid cancer

BACKGROUND

The early diagnosis of medullary thyroid carcinoma (MTC) is still a challenge in clinical practice. Based on ultrasound features, many MTC cases without suspicious characteristics are not categorized as high risk for malignancy. This study was designed to comprehensively investigate the ultrasonic features of MTC on ultrasound and help identify thyroid nodules with a high risk of MTC.

METHODS

Between 2017 and 2023, we retrospectively reviewed 116 consecutive thyroid nodules with a histologic diagnosis of MTC who had undergone preoperative ultrasound examination. According to the ultrasonic criteria for risk classification, nodules were classified as "ultrasound-high suspicious" (h-MTC) and "ultrasound-low suspicious" (l-MTC). Using the same database, a tumour size- and risk evaluation-matched control group comprising 62 lesions was randomly selected to compare the vascularity features of l-MTC disease.

RESULTS

We identified 85 h-MTC nodules (73.3%) and 31 l-MTC nodules (26.7%). For patients with l-MTC disease, 22/31 (71.0%) of the lesions were followed up for a period before fine needle aspiration (FNA) or surgery. We observed more penetrating branching vascularity in the l-MTC group than in the benign nodule group (23/31, 74.2% vs. 5/59, 4.8%, P < 0.001). We also showed that more CHAMMAS IV patterns (central blood flow greater than perinodular flow) (87.1% vs. 32.3%, P < 0.001)) and CHEN IV patterns (penetrating vascularity) (100% vs. 25.8%, P < 0.001) were found in l-MTC than benign nodules.

CONCLUSIONS

Vascularity features can help differentiate l-MTC from benign nodules; moreover, we report a novel sonographic vascularity pattern of l-MTC disease, penetrating branching vascularity. The utilization of vascularity features will help to identify MTC among nodules with low-intermediate suspicion by ultrasound risk classification to ensure appropriate clinical management.

Clinical Characteristics, Surgical Management, and Prognostic Factors of Medullary Thyroid Carcinoma: A Retrospective, Single-Center Study

Purpose: Medullary thyroid carcinoma (MTC) is a rare neuroendocrine malignancy with relatively early lymphatic metastatic spread. The clinical features of MTC remain controversial owing to the low incidence rate. This study aimed to analyze the clinical characteristics, prognostic factors, and long-term follow-up of MTC. Methods: Medical records of MTC patients treated at our hospital between December 2000 and November 2020 were reviewed retrospectively. Clinicopathologic features of MTC were analyzed using univariate and multivariate analyses. Cumulative survival rates were estimated using the Kaplan-Meier method. Results: In total, 152 patients with MTC were included. The rates of central and lateral lymph node metastases (LNM) were 52.0% and 42.8%, respectively. All patients were followed up with a median follow-up time of 43.5 (17.0−76.3) months. Univariate and multivariate analyses identified two independent factors associated with progressive disease. They were lateral LNM (p < 0.001) and lymph node ratio (LNR) >1/3 (p = 0.009). The 5-, 10-, and 15-year cumulative overall survival (OS) rates of MTC were 88.2%, 83.1%, and 76.2%, respectively. The 5-, 10-, and 15-year cumulative disease-free survival (DFS) rates were 61.8%, 48.6%, and 38.2%, respectively. Patients with stage I, II, and III disease had significantly longer OS and DFS than those with stage IV disease (p < 0.001). Conclusion: MTC is a rare endocrine malignancy and LNM is common. Patients with lateral LNM and LNR >1/3 are more likely to develop progressive disease. The long-term OS rates of MTC are good, but long-term DFS rates are poor.

Ultrasound features value in the diagnosis and prognosis of medullary thyroid carcinoma

PURPOSE

Ultrasound (US) is the most important imaging in the preoperative diagnosis of medullary thyroid carcinoma (MTC). MTC are easy to be misdiagnosed due to lacking typical malignant US features. This study investigated US features, clinical characteristics, prognosis, and detection methods, aimed to explore the association between US features and biological behavior, and improve early diagnosis of MTC.

METHODS

A total of 189 MTC patients were enrolled in the study. Based on US features, 29 MTC were categorized as "indeterminate" (i-MTC) and 160 MTC were categorized as "malignant" (m-MTC) according to Thyroid Imaging, Reporting and Data System published by America College of Radiology (ACR TI-RADS). We compared US features, clinical characteristics and prognosis between both groups. We analyzed cytological categories of fine needle aspiration (FNA) within each i-MTC and m-MTC group according to the 2017 Bethesda System for Reporting Thyroid Cytopathology (TBSRTC). We assessed the positive rate of FNA, frozen pathological examination, and preoperative serum calcitonin (Ctn) level in i-MTC and m-MTC groups.

RESULTS

Preoperative US features were significantly different in shape, margin, composition, echogenicity, and calcifications between i-MTC and m-MTC (p < 0.05). I-MTC showed a hypoechoic solid or solid-cystic nodule lacking malignant US features. While m-MTC was presented as a solid nodule with obviously malignant US features. There were significant differences in lymph node dissection, extent of tumor, lymph node metastasis, and TNM stage and prognosis between i-MTC and m-MTC (p < 0.05). Compared to m-MTC, i-MTC underwent central neck dissection more frequently rather than lateral neck dissection at the time of the initial operation; i-MTC had less extrathyroidal invasion and lymph node metastasis, earlier stage, higher rate of biochemical cure, and lower rate of structural persistence/recurrence (p < 0.05). The 2017 TBSRTC of i-MTC and m-MTC was significantly different (p < 0.05). Preoperative serum Ctn level had a higher diagnostic sensitivity for both i-MTC and m-MTC when comparing to FNA and frozen pathological examination (p < 0.05).

CONCLUSIONS

US features were associated with biological characteristics and prognosis of MTC. I-MTC lack malignant US features, preformed less aggressiveness, and better prognosis. TBSRTC according to FNA combined with serum Ctn were helpful for the detection of i-MTC.

Ultrasound features of medullary thyroid cancer as predictors of biological behavior

BACKGROUND

Medullary thyroid cancer (MTC) has more aggressive behavior and poor prognosis. Ultrasound (US) has facilitated the qualitative diagnosis of thyroid nodules, however, some MTC may be diagnosed as a benign nodule on ultrasound because ultrasound features of malignancy are lacking. The aim of the study was to investigate the association between ultrasound features and biological behavior of MTC.

METHODS

Ultrasound findings and medical records of patients with MTC between Jan 2015 to Jun 2017 were retrospectively reviewed at Tianjin Medical University Cancer Institute and Hospital. MTC were categorized using modified TI-RADS classification, then were classified as "malignant" (m-MTC) or "US-low-suspicious" (l-MTC). We compared the biological behavior between the two groups, and further analyzed the risk factors for the recurrence.

RESULTS

A total of 78 patients were enrolled, of which 55 m-MTC (70.5%) and 23 l-MTC (29.5%) were identified. The N staging of the m-MTC was significantly higher than that of l-MTC(P = 0.000). The preoperative serum Ct level in m-MTC were significantly higher than that of l-MTC(P = 0.035). Biochemical cure were more frequent in l-MTC than that of m-MTC (P = 0.002). Disease recurrence rates were 19.7% (14 of 71). Disease recurrence was more frequent in m-MTC than that of l-MTC (P = 0.013). Disease recurrence was positively associated with extrathyroid extension (P = 0.047), N staging (P = 0.003), preoperative serum Ct level (P = 0.009) and negatively associated with biochemical cure(P = 0.000). In multivariable Cox regression analysis, extrathyroid extension and biochemical cure were independent risk factors for recurrence of MTC.

CONCLUSIONS

L-MTC has a more indolent character than m-MTC. The extrathyroid extension and biochemical cure were independent risk factors for recurrence of MTC.

Correlation between Ultrasonic Features of Medullary Thyroid Carcinoma and Cervical Lymph Node Metastasis

The aim of this study was to investigate the factors that affect cervical lymph node metastasis (CLNM) in individuals with medullary thyroid carcinoma (MTC) in terms of ultrasonic characteristics and other parameters. Single-factor χ² analysis showed that the ultrasonic characteristics of tumor size >10 mm, unclear boundary, irregular pattern and capsular invasion, as well as pre-operative calcitonin level >302.50 pg/mL (p < 0.001) and age ≤52.50 y (p = 0.036), were risk factors for CLNM in individuals with MTC. Multivariate logistic regression analysis showed that age ≤52.50 y (odds ratio = 3.796; 95% confidence interval, 1.010-14.259; p = 0.048), irregular pattern (odds ratio = 5.262; 95% confidence interval, 1.200-23.084; p = 0.028) and tumor size >10 mm (odds ratio = 7.789; 95% confidence interval, 1.123-54.005; p = 0.038) were independent risk factors for CLNM in individuals with MTC. Individuals with MTC aged ≤52.50 y with an irregular pattern and tumor size >10 mm were more likely to develop CLNM. In addition, those with a pre-operative calcitonin level >302.50 pg/mL were more likely to have CLNM.

The KWAK TI-RADS and 2015 ATA guidelines for medullary thyroid carcinoma: Combined with cell block-assisted ultrasound-guided thyroid fine-needle aspiration

OBJECTIVE

To compare the value of the thyroid imaging reporting and data system proposed by Kwak (KWAK TI-RADS) and the 2015 American Thyroid Association (ATA) guidelines for diagnosis of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC). To confirm the role of cell block (CB)-assisted fine-needle aspiration (FNA) in final diagnosis of MTC.

DESIGN

Retrospective hospital-based cohort study.

PATIENTS

Ninety-three patients with 29 MTCs, 31 PTCs and 33 thyroid adenomas (TAs) who underwent thyroidectomy from January 2010 to May 2019 were retrospectively reviewed. The KWAK TI-RADS and ATA guidelines were used to assess each thyroid nodule. FNA, CB-assisted FNA and core needle biopsy (CNB) were performed in final diagnosis.

RESULTS

Age and ultrasound features (composition, echogenicity and shape) were significantly different between MTC and PTC. Sex and ultrasound features (echogenicity, margin and calcification) were significantly different between MTC and TA. The KWAK TI-RADS and ATA guidelines showed no significant difference for MTC (area under the curve [AUC]: 0.812 and 0.808; P = .37-.85) or PTC (AUC: 0.883 and 0.885; P = .25-.96). The KWAK TI-RADS and ATA guidelines showed high specificity and sensitivity for MTC (93.9% and 62.1%, 87.9% and 65.5%) and PTC (93.9% and 67.7%, 87.9% and 77.4%), respectively. For suspicious MTC (7 cases), CB-assisted FNA provide accuracy preoperative diagnosis.

CONCLUSIONS

Although the diagnostic performance of the TI-RADS and ATA guidelines is worse for MTC than PTC, the difference is not statistically significant. CB-assisted FNA should be performed in thyroid nodules with 4a or lower suspicion to avoid misdiagnosis of MTC.

Active surveillance as a management strategy for papillary thyroid microcarcinoma

Active surveillance (AS) can be considered as a treatment strategy for low risk papillary thyroid microcarcinoma (PTMC), with the absence of clinically apparent lymph nodes, extrathyroidal extensions, and distant metastasis. After reviewing the reports on AS of low risk PTMCs worldwide, we introduced AS, and discussed the selection criteria for active surveillance candidates based on different guidelines and the follow-up schedules. Moreover, the requirement of cytological diagnosis, progression evaluation methods, necessity of thyrotropin suppression, and medical costs were issues that both clinicians and patients considered. The usefulness of AS for low risk PTMC patients depended on accurate and confidential evaluation of patient risk. Clinicians may adopt measures like dynamic monitoring, risk stratification, and making personal follow-up schedules to minimize these potential risks. By appropriately selecting PTMC patients, AS can be an effective alternative treatment to immediate surgery.

Thyrotoxicosis with concomitant thyroid cancer

Thyrotoxicosis with concomitant thyroid cancer is rare and poorly recognized, which may result in delayed diagnosis, inappropriate treatment and even poor prognosis. To provide a comprehensive guidance for clinicians, the etiology, pathogenesis, diagnosis and treatment of this challenging setting were systematically reviewed. According to literatures available, the etiologies of thyrotoxicosis with concomitant thyroid cancer were categorized into Graves' disease with concurrent differentiated thyroid cancer (DTC) or medullary thyroid cancer, Marine-Lenhart Syndrome with coexisting DTC, Plummer's disease with concomitant DTC, amiodarone-induced thyrotoxicosis with concomitant DTC, central hyperthyroidism with coexisting DTC, hyperfunctioning metastases of DTC and others. The underlying causal mechanisms linking thyrotoxicosis and thyroid cancer were elucidated. Medical history, biochemical assessments, radioiodine uptake, anatomic and metabolic imaging and ultrasonography-guided fine-needle aspiration combined with pathological examinations were found to be critical for precise diagnosis. Surgery remains a mainstay in both tumor elimination and control of thyrotoxicosis, while anti-thyroid drugs, beta-blockers, 131I, glucocorticoids, plasmapheresis, somatostatin analogs, dopamine agonists, radiation therapy, chemotherapy and tyrosine kinase inhibitors should also be appropriately utilized as needed.

Reducing the Number of Unnecessary Thyroid Biopsies While Improving Diagnostic Accuracy: Toward the "Right" TIRADS

CONTEXT

The prevalence of thyroid nodules in the general population is increasingly high, and at least half of those biopsied prove to be benign. Sonographic risk-stratification systems are being proposed as "rule-out" tests that can identify nodules that do not require fine-needle aspiration (FNA) cytology.

OBJECTIVE

To comparatively assess the performances of five internationally endorsed sonographic classification systems [those of the American Thyroid Association, the American Association of Clinical Endocrinologists, the American College of Radiology (ACR), the European Thyroid Association, and the Korean Society of Thyroid Radiology] in identifying nodules whose FNAs can be safely deferred and to estimate their negative predictive values (NPVs).

DESIGN

Prospective study of thyroid nodules referred for FNA.

SETTING

Single academic referral center.

PATIENTS

Four hundred seventy-seven patients (358 females, 75.2%); mean (SD) age, 55.9 (13.9) years.

MAIN OUTCOME MEASURES

Number of biopsies classified as unnecessary, false-negative rate (FNR), sensitivity, specificity, predictive values, and diagnostic ORs for each system.

RESULTS

Application of the systems' FNA criteria would have reduced the number of biopsies performed by 17.1% to 53.4%. The ACR Thyroid Imaging Reporting and Data System (TIRADS) allowed the largest reduction (268 of 502) with the lowest FNR (NPV, 97.8%; 95% CI, 95.2% to 99.2%). Except for the Korean Society of Thyroid Radiology TIRADS, all other systems exhibited significant discriminatory performance but produced significantly smaller reductions in the number of procedures.

CONCLUSIONS

Internationally endorsed sonographic risk stratification systems vary widely in their ability to reduce the number of unnecessary thyroid nodule FNAs. The ACR TIRADS outperformed the others, classifying more than half the biopsies as unnecessary with a FNR of 2.2%.

Preoperative sonographic features of follicular thyroid carcinoma predict biological behavior: A retrospective study

Little is known regarding biological behavior of follicular thyroid carcinomas (FTCs) according to ultrasonography features. We investigated whether there was a difference in biological behavior between benign-looking FTCs (B-FTCs) and malignant-looking FTCs (M-FTCs).A total of 55 cases of FTC between January 2000 and December 2015 were included. B-FTCs were defined as showing none of the accepted ultrasonography criteria for malignancy, and M-FTCs were defined as showing at least one of the accepted ultrasonography criteria for malignancy. Clinicopathologic factors and sonographic features were compared between B-FTCs and M-FTCs. Based on the degree of invasiveness, FTCs were divided into minimally invasive FTCs (MI-FTCs) and widely invasive FTCs (WI-FTCs) on pathology. Sonographic features were compared between MI-FTCs and WI-FTCs.Compared with the patients with B-FTCs (31/55, 56.4%), the patients with M-FTCs showed a significantly higher prevalence of WI-FTCs, central lymph node metastases, lateral lymph node metastases as well as extrathyroidal extension (P < .001, P = .012, P = .031, and P = .032, respectively). M-FTCs with more than one malignancy features on ultrasonography showed a significantly higher prevalence of extrathyroidal extension than M-FTCs with only one ultrasonography malignancy feature (P = .022). Compared with MI-FTCs (41/55, 74.5%), an irregular shape, a spiculated/microlobulated boundary, no peripheral halo ring, hypoechogenicity and microcalcification were more frequent in WI-FTCs (P < .001, P = .003, P = .002, P = .015, and P = .016, respectively).Our results demonstrated that B-FTCs had better prognostic indicators than M-FTCs. Therefore, preoperative US features can serve as a useful tool for predicting biological behavior in FTC.

Medullary thyroid carcinoma: Application of Thyroid Imaging Reporting and Data System (TI-RADS) Classification

PURPOSE

To evaluate the applicability of ultrasound (US)-based Thyroid Imaging Reporting and Data System (TI-RADS) for evaluating medullary thyroid carcinoma (MTC).

MATERIALS AND METHODS

US images and medical records of patients with cytopathology-confirmed MTC between June 2003 and November 2016 were retrospectively reviewed. Four independent reviewers (two experienced and two inexperienced radiologists) evaluated 57 pre-operative US images of patients with MTC for shape, composition, echogenicity, margin, calcification of the MTC nodules, and categorized the nodules using TI-RADS classification. Weighted Kappa statistics was used to determine the inter-observer agreement of TI-RADS. Univariate and multivariate analyses were performed to assess US findings associated with lymph node metastasis.

RESULTS

Ninety-five percent of nodules were classified as either high suspicion (68%) or intermediate suspicion (26%). The overall inter-rater agreement was good (Kappa 0.84, agreement 91.52%), and inexperienced reviewers also showed good agreements with the most experienced reviewer (weighted Kappa 0.73 and 0.81). According to the univariate analysis, TI-RADS category 5, shape, microcalcification, and extrathyroid extension were significantly associated with lymph node metastasis in MTC patients (p = 0.003, 0.008, 0.001, and 0.021, respectively). As per the multivariate analysis, the presence of microcalcification and the irregular shape of the nodule were significantly associated with metastatic lymph nodes in MTC patients (odds ratio, 26.6; 95% CI, 2.7-263.7, p = 0.005, odds ratio, 14.7; 95% CI, 1.3-170, p = 0.031, respectively).

CONCLUSION

TI-RADS is applicable for the evaluation of MTC nodules with good inter-observer agreement.

Preoperative Clinical and Sonographic Predictors for Lateral Cervical Lymph Node Metastases in Sporadic Medullary Thyroid Carcinoma

BACKGROUND

Total thyroidectomy and cervical lymph node (LN) dissection is generally recommended in patients with medullary thyroid carcinoma (MTC). However, there is no clear evidence for whom to perform prophylactic lateral neck dissection in MTC patients without evident lateral cervical lymph node (LCLN) metastasis in preoperative images. This study evaluated the preoperative features for predicting the LCLN metastasis of MTC.

METHODS

The study included 26 MTC patients with LCLN metastasis at initial surgery (N1b group) and 47 MTC patients without any LN metastasis or recurrence of disease (N0-NED group). The association between LCLN metastasis and preoperative clinical and sonographic characteristics (size, location, solid component, shape, margin, echogenicity, calcification, and subcapsular location of the tumor) were evaluated.

RESULTS

There were no significant differences in age and sex between the N1b and N0-NED groups. Preoperative serum levels of calcitonin >65 pg/mL were associated with LCLN metastasis (p < 0.001). In preoperative neck ultrasonography (US), patients in the N1b group were more commonly found with a larger tumor (>1.5 cm) of irregular shape with a spiculated margin and a subcapsular location than those in the N0-NED group (p = 0.029, p < 0.001, p < 0.001, and p < 0.001, respectively). Increases in the number of these LCLN metastasis-related features were significantly associated with higher risk for LCLN metastasis (p < 0.001). The presence of two or more predictors was an appropriate cutoff point for predicting LCLN metastasis of MTC with 73.1% sensitivity and 91.5% specificity.

CONCLUSIONS

MTC tumors with high preoperative calcitonin levels (>65 pg/mL), larger size (>1.5 cm), irregular shape, spiculated margins, and subcapsular locations in the neck US are at higher risk for LCLN metastasis. MTC patents with fewer than two predictors might be suitable for treatment without prophylactic LCLN dissection.

Active Surveillance of Papillary Thyroid Microcarcinoma: A Mini-Review from Korea

In Korea, the incidence of thyroid cancer increased explosively in the early 2000s, and reached a plateau in the early 2010s. Most cases of newly diagnosed thyroid cancer are small indolent microcarcinoma and could be good candidates for active surveillance (AS) instead of immediate surgery. Many considerations must be taken into account for establishing selection criteria for candidates for AS of papillary thyroid microcarcinoma (PTMC), including the characteristics of the tumor, the patient, and the medical team. If possible, AS of PTMC should be a part of a prospective clinical trial to ensure long-term safety and to identify clinical and/or molecular markers of the progression of PTMC. In this review, we discuss lessons regarding surgical interventions for PTMC, and then describe the concept, application, caveats, unanswered questions, and future perspectives of AS of PTMC. For appropriately selected patients with PTMC, AS can be a good alternative to immediate surgery.