Serum Calcitonin-Negative Medullary Thyroid Carcinoma: A Case Series of 19 Patients in a Single Center

Non-papillary thyroid carcinoma diagnoses in The Bethesda System for Reporting Thyroid Cytopathology categories V and VI: An institutional experience

BACKGROUND

The non-papillary thyroid carcinoma (PTC) subgroups of The Bethesda System for Reporting Thyroid Cytopathology (TBSRTC) categories V (Suspicious for malignancy) and VI (Malignant) are rare, and specific tumor typing is difficult. We aimed to analyze histologic outcomes and to investigate the points of caution.

METHODS

We reviewed the electronic database and identified 12,215 cases of thyroid fine-needle aspiration cytology between 2013 and 2022. In total, 2783 patients were diagnosed with TBSRTC V or VI. Of these, 51 patients with non-PTC diagnosis were identified. Histological outcomes were analyzed with the cytologic findings.

RESULTS

The subgroups of non-PTC diagnoses in TBSRTC category V or VI consisted of medullary thyroid carcinoma (MTC) (13/51, 25.5 %), anaplastic thyroid carcinoma (3/51, 5.9 %), lymphoma (2/51, 3.9 %), metastatic tumor (4/51, 7.8 %), and malignant, not otherwise specified (NOS) (29/51, 56.9 %). The concordance rate of the histological outcomes was 30 % (12/40), predominantly comprising MTC cases. The obscuring factors for specific tumor typing in the suspicious for malignancy/malignant NOS cytology diagnosis group was mixed pattern of well differentiated thyroid carcinoma and less differentiated carcinoma cells (9/24, 37.5 %), low cellularity (7/24, 29.2 %) and a history of non-thyroid organ malignancy (6/24, 25 %). The less differentiated carcinoma component in mixed pattern consisted of 2 poorly differentiated thyroid carcinomas, 2 anaplastic thyroid carcinomas, 4 high-grade PTCs and 1 high-grade MTC.

CONCLUSION

The high-grade feature of PTC or MTC cytology is a noteworthy obscuring factor in specific tumor typing of non-PTC cytology diagnosis.

Time Kinetics and prognosis roles of calcitonin after surgery for medullary thyroid carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) is a malignant tumor with low incidence. Currently, most studies have focused on the prognostic risk factors of MTC, whatever, time kinetic and risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) are yet to be elucidated.

METHODS

A retrospective study was conducted for 190 MTC patients. Risk factors related to calcitonin normalization (CN) and biochemical persistence/recurrence (BP) were analyzed. The predictors of calcitonin normalization time (CNT) and biochemical persistent/recurrent time (BPT) were identified. Further, the prognostic roles of CNT and BPT were also demonstrated.

RESULTS

The 5- and 10-year DFS were 86.7% and 70.2%, respectively. The 5- and 10-year OS were 97.6% and 78.8%, respectively. CN was achieved in 120 (63.2%) patients, whereas BP was presented in 76 (40.0%) patients at the last follow up. After curative surgery, 39 (32.5%) and 106 (88.3%) patients achieved CN within 1 week and 1 month. All patients who failed to achieve CN turned to BP over time and 32/70 of them developed structural recurrence. The median time of CNT and BPT was 1 month (1 day to 84 months) and 6 month (3 day to 63months), respectively. LNR > 0.23 and male gender were independent predictors for CN and BP. LNR > 0.23 (Hazard ratio (HR), 0.24; 95% CI,0.13-0.46; P < 0.01) and male gender (HR, 0.65; 95% CI, 0.42-0.99; P = 0.045) were independent predictors for longer CNT. LNR > 0.23 (HR,5.10; 95% CI,2.15-12.11; P < 0.01) was still the strongest independent predictor followed by preoperative serum Ctn > 1400ng/L (HR,2.34; 95% CI,1.29-4.25; P = 0.005) for shorter BPT. In survival analysis, primary tumor size > 2 cm (HR, 5.81; 95% CI,2.20-15.38; P < 0.01), CNT > 1 month (HR, 5.69; 95% CI, 1.17-27.61; P = 0.031) and multifocality (HR, 3.10; 95% CI, 1.45-6.65; P = 0.004) were independent predictor of DFS.

CONCLUSION

Early changes of Ctn after curative surgery can predict the long-term risks of biochemical and structural recurrence, which provide a useful real-time prognostic information. LNR significantly affect the time kinetic of biochemical prognosis. Tumor burden and CNT play a crucial role in MTC survival, the intensity of follow-up must be tailored accordingly.

Changes of biochemical factors and the effect on recurrence of medullary thyroid carcinoma after surgery

Objective

Medullary thyroid carcinoma (MTC) is a rare malignancy secreting calcitonin (Ctn). We aimed to analyze the relationship between Ctn levels at different time points in patients with MTC, and evaluate its predictive effect on recurrence.

Methods

A retrospective study of patients diagnosed with MTC in a large medical center were conducted in northern China. The interrelationships between preoperative Ctn, normalization of postoperative serum Ctn at the first month (NPS), and long-term biochemical cure as well as their predicting roles on structural recurrence were assessed.

Results

A total of 212 patients were included in this study. The median follow-up time was 59.5 months. The 5- and 10-year cumulative disease-free survival rates were 81.5 % and 66.8 %, respectively. NPS (OR: 216.33, 95 % CI: 28.69-1631.09, P < 0.001) and absence of structural recurrence (OR: 61.71, 95 % CI: 3.90-975.31; P = 0.003) were associated with biochemical cure. Non-biochemical cure (OR: 28.76; 95 % CI: 2.84-290.86; P = 0.004, HR: 14.63, 95 % CI: 2.27-94.07, P = 0.005), larger tumor size (OR: 8.79, 95 % CI: 2.12-36.40, P = 0.003, HR: 5.41, 95 % CI: 2.04-14.37, P = 0.001), and multifocality (OR: 4.02, 95 % CI: 1.06-15.17, P = 0.040, HR: 3.00, 95 % CI: 1.18-7.60, P = 0.021) were unfavorable independent predictors of structural recurrence and disease-free survival. For sporadic MTC confined to the thyroid lobe, there was no difference in biochemical or structural prognosis between the different surgeries in the subgroup analysis.

Conclusions

NPS, rather than preoperative Ctn, predicted long-term biochemical cure for MTC. Non-biochemical cure, larger tumor burden including larger tumor size and multifocality at initial surgery, served as worse prognostic predictors.

Survival Outcomes of Medullary Thyroid Cancer With and Without Amyloid Deposition

OBJECTIVE

Amyloid deposition within tumor stroma is a distinctive histologic feature of medullary thyroid cancer (MTC). However, its prognostic significance remains uncertain. We aimed to elucidate the impact of amyloid status on survival outcomes in a large cohort.

METHODS

The Surveillance, Epidemiology, and End Results registry was queried to identify patients diagnosed with MTC from 2000 to 2019. Patients with amyloid-positive (International Classification of Diseases for Oncology, third edition code 8345/3) and amyloid negative (International Classification of Diseases for Oncology, third edition code 8510/3) tumors were analyzed. Overall and disease-specific survival were compared between matched cohorts using Kaplan-Meier and Cox proportional hazards analyses.

RESULTS

Of the 2526 MTC patients, 511 of which were amyloid-positive and 2015 that were amyloid negative. Amyloid-positive patients displayed lower T stage (T3/4: 28% vs 85%, P < .001) and less extrathyroidal extension (11.3% vs 81.6%, P < .001). No difference in distant metastasis rate was observed between groups (14.5% vs 14.4%, P = .98). However, amyloid-positive patients showed a tendency for distal lymph node metastasis (1.2% vs 0.3%, P = .020). On univariate analysis, amyloid-positive status showed comparable overall survival times (mean 172.2 vs 177.8 months, P = .17), but a trend toward worse cancer-specific survival (hazard ratios [HR] = 1.31, 95% CI = 0.99-1.71, P = .051). After adjusting for covariates, amyloid deposition did not independently predict overall (HR = 1.15, 95% CI = 0.91-1.47, P = .25) or cancer-specific survival (HR = 1.30, 95% CI = 0.96-1.77, P = .09). Initiating therapy later than 1 month following diagnosis was associated with worse overall survival (HR = 1.25, 95% CI = 1.02-1.54, P = .029).

CONCLUSIONS

The presence of amyloid in MTC paradoxically associates with lower T stage yet exhibits a trend toward worse cancer-specific mortality. Amyloid deposition alone does not independently influence prognosis. Delayed treatment adversely impacted overall survival.

Optimizing Diagnostic Accuracy of Fine Needle Aspiration Biopsy Calcitonin Measurements in Detecting Medullary Thyroid Carcinoma

Background: The optimal cutoff value of calcitonin (Ctn) levels measured using an electrochemiluminescence immunoassay (ECLIA) obtained from the washout fluid of fine needle aspiration (FNA-Ctn) for the diagnosis of medullary thyroid carcinoma (MTC) is currently not established. We evaluated the diagnostic accuracy and clinical utility of FNA-Ctn for the diagnosis and location of MTC in patients with nodular or multinodular goiters. Methods: This was a case-control study nested on a prospective multicenter cohort of patients with nodular or multinodular goiter, normal or elevated serum Ctn, and thyroidectomy indications. Ctn and FNA-Ctn were measured using ECLIA methodology before surgery. From this nested cohort, MTC cases and controls (non-medullary pathology) were identified from the final pathological analysis. Cumulative incidence sampling of controls was randomly performed at a ratio of 1:2. Sensitivity, specificity, and area under the receiver operator curve (AUROC) were calculated for patients and the total number of thyroid nodules. Results: From 1272 patients included in the prospective cohort, 50 MTC cases and 105 controls were included. In this study, 286 thyroid nodules were evaluated (63 MTC and 223 non-MTCs). The median serum Ctn value was significantly higher in cases (525 pg/mL [interquartile range (IQR), 162.5-1.200]) than in controls (1.6 pg/mL [IQR, 0.5-5.6]; p < 0.001). The median FNA-Ctn value was significantly higher in MTC nodules (3.100 pg/mL [IQR, 450-45,200]) than in non-MTC nodules (0.5 pg/mL [IQR, 0.5-0.5]; p < 0.0001). In 11 MTC patients with multinodular goiter, the FNA-Ctn value was significantly higher in non-medullary nodules located in the same lobe where an MTC nodule was diagnosed (p = 0.0002). Overall, the FNA-Ctn AUROC was 0.99 [95% confidence interval, 0.98-1.0], and a threshold of ≥220 pg/mL showed 100% sensitivity and 98% specificity for MTC diagnosis. Conclusions: The use of FNA-Ctn measured by ECLIA showed adequate diagnostic accuracy for MTC diagnosis. Moreover, it may be clinically useful for localization in multinodular goiter when lobectomy is considered. Clinical Trial Registration: Clinicaltrials.gov NCT06067594.

Neuroendocrine metastasis to the thyroid from unknown primary and extrathyroidal disease response to peptide receptor radionuclide therapy

Neuroendocrine tumor (NET) metastasis to the thyroid is rare, and its presentation as the first manifestation of primary malignancy elsewhere is even more uncommon. We present a case of a 41-year-old female who underwent biopsy of enlarging thyroid nodules with findings suspicious for medullary thyroid cancer (MTC). Subsequent thyroidectomy demonstrated NET of unknown primary in the left lower lobe. Immediate workup with 68Ga-DOTATATE-PET/CT revealed abnormal somatostatin receptor (SR) expressing lesions in the liver, right cervical nodes, thoracic paravertebral soft tissue, precoccygeal soft tissue, and right acetabulum concerning for sites of neuroendocrine malignancy. Due to disease progression while on octreotide injections, a decision was made at the multidisciplinary NET board for the patient to receive peptide receptor radionuclide therapy (PRRT) which includes 4 cycles of 77Lu-DOTATATE (Lutathera). The patient had no side effects nor toxicities during the 8 months of PRRT and achieved a partial treatment response in the early post-treatment scan at 6 weeks. This case illustrates the importance of distinguishing NET metastasis to the thyroid from MTC to ensure appropriate workup and treatment as well as predict the response of neuroendocrine malignancies to PRRT based on the visualized overexpression of SR in the SR-PET scans, despite the organ of origin.

Circulating cell-free DNA (cfDNA) in patients with medullary thyroid carcinoma is characterized by specific fragmentation and methylation changes with diagnostic value

Medullary Thyroid Carcinoma (MTC) is a rare neuroendocrine tumour whose diagnosis includes evaluating calcitonin serum levels, which can present fluctuations unrelated to MTC. Here, we investigated circulating DNA fragmentation and methylation changes as potential biomarkers using ddPCR on cell-free DNA (cfDNA) isolated from the plasma of MTC patients. For cfDNA fragmentation analysis, we investigated the fragment size distribution of a gene family and calculated short fragment fraction (SFF). Methylation analyses evaluated the methylation levels of CG_16698623, a CG dinucleotide in the MGMT gene that we found hypermethylated in MTC tissues by analyzing public databases. The SFF ratio and methylation of CG_16698623 were significantly increased in plasma from MTC patients at diagnosis, and patients with clinical remission or stable disease at follow-up showed no significant SFF difference compared with healthy subjects. Our data support the diagnostic value of cfDNA traits that could enable better management of MTC patients.

Partial preservation of the normal thyroid gland based on tumor diameter may be possible in small medullary thyroid carcinoma: a two-center 15-year retrospective study

Background

At present, there are some controversies in the formulation of surgical protocol for small medullary thyroid carcinoma(s-MTC). We wanted to explore the feasibility of normal thyroid gland retention in small medullary thyroid carcinoma based on different tumor diameters and its prognostic impact on the tumor.

Methods

The data of patients with stage T1 MTC treated at Tianjin Cancer Hospital and Sichuan Cancer Hospital from 2006 to 2021 were analyzed. The tumor diameters of 0.5 cm and 1.0 cm were used as dividing points. The outcomes were tumor recurrence, metastasis, or patient death. Survival was estimated by the Kapan-Meier curve.

Results

A total of 121 T1 s-MTC patients were included, including 55 with total thyroidectomy (TT) and 66 with subthyroidectomy (Sub-TT). There were eleven cases of tumor recurrence and metastasis, and four patients died. When the tumor diameter was 1.0 cm as the cut-off point, tumor diameter (p = 0.010), TT (p = 0.028), unilateral and bilateral type (p = 0.009), and TNM staging (p = 0.007) had significant effects on progression-free survival (PFS). The tumor diameter, unilateral and bilateral type, and TT were risk factors for the prognosis of T1 MTC (p < 0.05).

Conclusion

The tumor diameter of 1.0 cm can be used as a cut-off point for stage T1 MTC. Alt-hough there was no significant difference in overall survival (OS) between T1a and T1b in patients, tumor diameter significantly influenced PFS. TT is not necessary for patients with sporadic MTC with T1a.

Update on Calcitonin Screening for Medullary Thyroid Carcinoma and the Results of a Retrospective Analysis of 12,984 Patients with Thyroid Nodules

BACKGROUND

We provide an update on calcitonin (Ctn) screening for the early detection of medullary thyroid carcinoma (MTC) and present the results of a large single-center analysis evaluating sex-specific cut-off-levels and long-term courses.

METHODS

A total of 12,984 consecutive adult patients (20.1% male and 79.9% female) with thyroid nodules who had undergone routine Ctn measurement were retrospectively analyzed. Patients with confirmed suspicious Ctn values were referred for surgery.

RESULTS

Ctn measurements were elevated in 207 (1.6%) patients, with values below twice the sex-specific reference limit in 82% of these cases. Further clarification was possible in 124/207 cases, of which MTC could be ruled out in 108 cases. Histopathological assessment confirmed MTC in 16/12,984 patients.

CONCLUSIONS

Our extrapolated MTC prevalence of 0.14% is significantly lower than that described in early international screening studies. The stimulation test can usually be dispensable when using a decision-making concept based on sex-specific basal Ctn cut-off values. Ctn screening is recommended even in patients with very small thyroid nodules. High quality standards in pre-analytics, laboratory measurements, and the interpretation of data must be ensured, as well as close interdisciplinary cooperation between medical disciplines.

Diagnostic value and cost-effectiveness of FNA-CT versus FNAC for medullary thyroid carcinoma

OBJECTIVE

To evaluate the diagnostic performance and cost-effectiveness of calcitonin assays in fine-needle aspiration washout fluid (FNA-CT) compared to fine-needle aspiration cytology (FNAC) for medullary thyroid carcinoma (MTC).

METHODS

A total of 27,404 patients from three medical centres between January 2020 and May 2022 were screened for serum calcitonin (sCT). Of whom, 223 patients met endpoints and were enroled for analyses. Based on sCT levels, patients were divided into two groups (group 1: 10 pg/ml< sCT ≤100 pg/ml and group 2: sCT > 100 pg/ml). The diagnostic performance and cost-effectiveness of FNA-CT and FNAC were compared.

RESULTS

Most patients (N = 25,228; 92.1%) with thyroid nodules had normal sCT levels. In group 1, 24 and 167 nodules were diagnosed as MTC and non-MTC lesions, respectively. FNA-CT showed better performance in diagnosing MTC than FNAC in terms of sensitivity (100.0% vs. 58.3%), negative predictive value (100.0% vs. 94.3%), and overall accuracy (100.0% vs. 94.7%). In group 2, 67 and 7 nodules were diagnosed as MTC and non-MTC lesions, respectively. The diagnostic performance of FNA-CT was superior to FNAC in terms of sensitivity (100.0% vs. 64.2%), negative predictive value (100.0% vs. 22.6%), and overall accuracy (100.0% vs. 67.6%). Furthermore, analysis from the decision tree model showed that FNA-CT was a cost-effective tool for diagnosing MTC lesions.

CONCLUSIONS

FNA-CT can serve as an auxiliary and cost-effective approach for patients with indeterminate sCT levels to detect occult MTC lesions. FNA-CT can be recommended for patients with sCT >100 pg/ml to overcome the high false-negative rate of FNAC.

Radiomics Features of Different Sizes of Medullary Thyroid Carcinoma (MTC) and Papillary Thyroid Carcinoma (PTC) Tumors: A Comparative Study

Background:

Radiomics strategies exhibit great promise in the context of thyroid nodule diagnosis. This study aimed to compare radiomics features of different sizes of medullary thyroid carcinoma (MTC) and papillary thyroid carcinoma (PTC) tumors and to compare the efficiency of radiomics approaches as a means of differentiating between these tumor types.

Methods:

In total, 86 MTC and 330 PTC nodules were divided into the macronodular (>10 mm) and micronodular (⩽10 mm) categories. The radiomics features of these nodules were analyzed to identify independent prognosis factors and evaluate the efficacy of individual and combined indicators as predictors of tumor type.

Results:

In total, 12 radiomics features were found to differ significantly between MTC and PTC macronodules, while 6 differed significantly between MTC and PTC micronodules. Shape 2D_Sphericity, firstorder_Skewness, glrlm_RunLengthNonUniformity, glszm_GrayLevelNonUniformity, and glszm_SizeZoneNonUniformity were features that were independently associated with the differential diagnoses of MTC and PTC macronodules. Receiver operating characteristic (ROC) curve analyses of the efficacy of these 5 single indicators and a combined indicator composed thereof yielded area under the curve (AUC) values of 0.621, 0.678, 0.704, 0.762, 0.747, and 0.824, respectively, with respective sensitivities of 55.3%, 43.0%, 53.1%, 56.3%, 46.9%, and 65.6%, and respective specificity values of 65.6%, 89.1%, 81.6%, 88.8%, 95.0%, and 91.1%. The glrlm_RunEntropy and glszm_SizeZoneNonUniformity features were identified as independent factors associated with the differential diagnoses of MTC and PTC micronodules. Receiver operating characteristic curve analyses of the efficacy of these 2 single indicators and a combined indicator composed thereof yielded respective AUC values of 0.678, 0.678, and 0.771; Sensitivities of 57.0%, 72.7%, and 72.7%; and specificities of 77.3%, 64.2%, and 77.5%.

Conclusions:

A range of different radiomics features can enable effective differentiation between MTC and PTC nodules of different sizes. Moreover, analyses of combinations of radiomics features yielded diagnostic efficiency values higher than those associated with single radiomics features, highlighting a more reliable approach to diagnosing MTC and PTC tumors.

Oncologic outcomes of calcitonin-negative medullary thyroid carcinoma

OBJECTIVE

Calcitonin (Ct)-negative medullary thyroid carcinoma (MTC) is a rare neuroendocrine tumor. This study aimed to clarify its incidence, clinicopathologic characteristics, management, and treatment outcome.

METHODS

We retrospectively analyzed data of patients with primary MTC. Patients were divided into two groups according to the preoperative serum Ct level (Ct-negative and Ct-positive). The demographic, pathologic, and molecular characteristics, and treatment outcomes were compared between the two groups. In the Ct-negative group, we analyzed the association between the operation type and treatment outcome.

RESULTS

Of the total 312 patients, 24 were diagnosed with Ct-negative MTC. The rate of lymph node metastasis was significantly higher in the Ct-positive than in the Ct-negative group (47.9% vs. 0%, p<0.001). The proportion of patients with Ki-67 ≤10% was significantly higher in the Ct-negative than in the Ct-positive group (87.5% vs. 38.2%, p<0.001). Excellent response was achieved by 91.7% and 34.7% of patients in the Ct-negative and Ct-positive groups, respectively (p<0.001). In the Ct-negative group, excellent response was achieved by all female patients, but only 50% of male patients.

CONCLUSIONS

Ct-negative MTC is rare and unlikely to develop lymph node metastasis. Unilateral lobectomy tends to provide a satisfactory chance of excellent response; however, this requires further validation.