Routine calcitonin measurement in nodular thyroid disease management: is it worthwhile?

Diagnostic challenges in calcitonin negative medullary thyroid carcinoma: a systematic review of 101 cases

Background

Calcitonin-negative medullary thyroid carcinoma (CNMTC), a rare form of MTC characterized by classic histopathology with normal serum calcitonin levels, presents a diagnostic challenge. This systematic review aims to summarize the clinical and pathological features of CNMTC and evaluate the utility of alternative biochemical markers.

Methods

Eligibility criteria for this systematic review included patients with a confirmed histopathological diagnosis of medullary thyroid carcinoma (MTC), normal preoperative serum calcitonin levels, or negative immunohistochemical (IHC) stain for calcitonin. A comprehensive electronic search strategy was employed on PubMed, Scopus, and Embase databases from January 1st, 1950, to March 9th, 2023.

Results

This systematic review consists of 32 studies with 101 patients (66% females, 33% males) with a mean age of 52.2 years. All patients had a preoperative serum calcitonin level below the upper reference limit. Out of 101 patients, only seven underwent the Pentagastrin Stimulation Test (PST), only two patients had elevated calcitonin levels after stimulation. A total of 59 patients were tested for carcinoembryonic antigen (CEA) levels, and the majority tested normal (n=51, 86.4%). A total of 57 patients (61.2%) were found to have positive IHC staining on operative specimens for calcitonin. No recurrence was reported in the majority of cases, only 10 patients (9.9%) experienced recurrence.

Conclusions

Despite the rarity of CNMTC, it is crucial to maintain a high level of suspicion when evaluating thyroid nodules. Total thyroidectomy with central neck dissection remains as the primary treatment. A multimarker approach may improve the sensitivity and specificity of CNMTC diagnosis and surveillance, particularly when calcitonin and CEA levels are inconclusive.

Prevalence and significance of indeterminate calcitonin values in patients with thyroid nodules: A systematic review and meta-analysis

BACKGROUND

Although calcitonin (Ctn) measurement is recognized as the most accurate diagnostic test for medullary thyroid carcinoma (MTC), its routine execution is not universally accepted for several reasons, including the lack of recommendations for managing indeterminate Ctn values (ICV); such as 10-to-100 pg/mL. This study aimed to gather data on 1) the frequency of ICV among patients undergoing Ctn test and 2) the MTC rate among patients with ICV.

METHODS

This review was conducted according to the Meta-analyses Of Observational Studies in Epidemiology guidelines. PubMed and Cochrane databases were searched, with no language restrictions. The final search was completed on January 2023. Then, quality assessment and proportion meta-analyses were performed.

RESULTS

The online search retrieved 233 articles and 15 were included for quantitative analysis. The risk of bias was low. The number of patients undergone Ctn testing was 29,533. The pooled percentage of those with ICV was 1.7% (95% confidence interval [CI]:1.2-2.3). The pooled proportion of MTC incidence among patients with ICV was 9.6% (95% CI:5-14.1). Heterogeneity was explained by the covariates of Ctn assay sensitivity and the resection rate. The subgroup with Ctn 10-20 pg/mL showed a significantly lower MTC rate than the subgroup with Ctn 20-100 pg/mL.

CONCLUSIONS

The percentage of ICV among patients with thyroid nodules who underwent Ctn testing is negligible. The rate of MTC in patients with ICV cannot be overlooked. Among the ICV intervals, the risk of MTC increases significantly when Ctn is above 20 pg/mL.

Novel Therapeutics and Treatment Strategies for Medullary Thyroid Cancer

Medullary thyroid cancer is a rare thyroid malignancy with unique management considerations. In general, small intrathyroidal tumors are cured by total thyroidectomy with central compartment dissection, while large tumors and those with disease spread to regional lymph nodes and distant organs (most commonly lung, liver, and bone) are more difficult to cure. The last decade has seen significant progress in the treatment of advanced MTC, largely due to the discovery and availability of novel targeted therapies, including new drugs specifically targeting the RET protooncogone.

Diagnostic Challenges of Medullary Thyroid Carcinoma

BACKGROUND

Medullary thyroid carcinoma (MTC) comprises 1-2% of all thyroid cancers, yet 15% of all thyroid cancer-related deaths. While up to 20% of cases may be predicted due to autosomal dominant germline mutations, 80% of cases are sporadic. However, due to non-specific presenting symptoms and diagnostic imaging, prompt diagnosis and treatment has remained elusive. This article will further investigate the limitations of MTC diagnosis and look into future areas for diagnostic improvement.

METHODS

Relevant articles were identified using a systematic PubMed and Google Scholar search.

RESULTS

Prophylactic total thyroidectomy for the 20% of MTC cases that are present in autosomal dominant disorder provides definitive treatment. Serum calcitonin (Ctn) screening has several technical limitations due to population variability and laboratory assay interference, but advances in laboratory technology and combined use with fine needle aspiration increase its sensitivity. Other serum assays such as carcinoembryonic antigen and procalcitonin have limited applicability. Thyroid ultrasound remains the gold standard for the initial diagnostic planning, with limited application for CT, MRI, and PET imaging.

CONCLUSION

With complete surgical resection the only definitive treatment, early MTC diagnosis has presented an elusive challenge, mainly due to its relative rarity and difficulty in finding an economic screening strategy. Careful family history combined with fine needle aspiration with serum Ctn analysis can improve diagnostic sensitivity and specificity to greater than 95%.

Diagnostic accuracy of routine calcitonin measurement for the detection of medullary thyroid carcinoma in the management of patients with nodular thyroid disease: a meta-analysis

OBJECTIVE

The usefulness of routine calcitonin measurement for early detection of medullary thyroid carcinoma (MTC) in patients with nodular thyroid disease (NTD) has been investigated in various studies. Recently, a Cochrane review has been published on this issue, but a meta-analysis is lacking yet. Therefore, we performed this meta-analysis.

METHODS

We performed an electronic search using PubMed/Medline, Embase and the Cochrane Library. Studies assessing the diagnostic accuracy of routine calcitonin measurement for detecting MTC in patients with NDT were selected. Statistics were performed by using Stata software, risk of bias was assessed using Review Manager version 5.3.

RESULTS

Seventeen studies, involving 74,407 patients were included in the study. Meta-analysis, using the bivariate random effects model and the hierarchical summary receiver operating characteristic (HSROC) curve revealed the following pooled estimates: sensitivity 0.99 (95% CI, 0.81-1.00), specificity 0.99 (95% CI, 0.97-0.99), positive likelihood ratio (L+) 72.4 (95% CI, 32.3-162.1), and negative likelihood ratio (L-) 0.01 (95% CI, 0.00-0.23). Meta-regression analysis showed that the threshold of basal calcitonin is an independent factor, but in particular performing stimulation test is not an independent factor.

CONCLUSIONS

We showed that routine basal serum calcitonin measurement in the management of patients with thyroid nodules is valuable for the detection of MTC. However, the published cut-off values should be considered and, if applicable, the patients monitored in a wait-and-see strategy by experienced physicians to avoid overtreatment.

Medullary Thyroid Cancer with Paraganglioma-Like Pattern Diagnosed During Pregnancy: A Case Report and Literature Revision

INTRODUCTION

Medullary thyroid carcinoma (MTC) is an infrequent thyroid malignancy rarely observed and managed during pregnancy. An accurate diagnostic workup is extremely important in this clinical setting to correctly diagnose and treat the disease, avoiding both maternal and fetal complications.

OBJECTIVE

We report our experience in managing an MTC incidentally diagnosed during pregnancy in a 28-year female, highlighting critical aspects through the diagnostic workup. Additionally, we provide a literature revision searching on PubMed terms related to "medullary thyroid carcinoma", "primary thyroid paraganglioma", "paraganglioma-like medullary thyroid cancer" in relationship with a nodular appearance at neck US, serum CT measurement, cytological and histological findings.

METHODS

Specimens for cytological evaluation were stained with the Papanicolaou method while tissue sections were stained with hematoxylin and eosin and Congo red stain. Immunohistochemical evaluation was also performed for thyroid transcription factor-1, enolase, thyroglobulin, cytokeratin, chromogranin A, S-100 protein, glial fibrillary acidic protein, calcitonin and Ki-67.

RESULTS

Serum CT was incidentally found to be elevated in two consecutive venous samples. However, the cytological assessment of the fine needle aspiration (FNAc) showed "cells with round-shaped nuclei and granular chromatin, organized to form nests or syncytial flaps, scattered among histocytes, and immunocytochemical positivity for CT, thyroid transcriptional factor-1, cytokeratin, S-100 protein", highlighting a suspicion of both MTC and intrathyroidal paraganglioma. MTC was finally supposed after the evidence of a really elevated CT (3,726 pg/ml) measurement in the FNA washout fluid. After a careful discussion about both risks and benefits, the patient decided to postpone the surgery after the delivery.

CONCLUSION

The histological diagnosis finally confirmed a rare case of paraganglioma-like MTC (T1 N0 Mx), emphasizing the complexity of our differential diagnosis, between an MTC and a thyroidal paraganglioma. In similar cases, due to a relevant impact on surgical timing, patients should be adequately informed about both risk and benefits of the surgery during pregnancy, and a careful management of the disease is required until and after surgery.

Cost-effectiveness of routine calcitonin screening and fine-needle aspiration biopsy in preoperative diagnosis of medullary thyroid Cancer in the United States

OBJECTIVES

examine the cost-effectiveness of routine Calcitonin (Ctn) screening test in the United States.

MATERIALS AND METHODS

Markov chain model was developed that compares fine-needle aspiration biopsy (FNAB) with Ctn screening vs. FNAB-only in the evaluation of a thyroid nodule with non-highly suspicious findings. Follow-up time was set as 10 years. Costs and probabilities values were obtained from literature, and National Cancer Database. Cost data is expressed in U.S$ and effectiveness is expressed in Quality-adjusted-life-year (QALY). Incremental cost-effectiveness ratio (ICER) was calculated comparing both study arms.

RESULTS

Routine Ctn screening was cost-effective compared to FNAB-only in all tested categories except when cutoff value of 10 pg/ml was applied. Among the tested categories, the application of universal routine Ctn screening with Ctn value > 50 pg/ml considered a positive test produced the most cost-saving scenario. The final accrued cost at the end of 10 years in the FNAB-only arm was $4238.93 with a final effectiveness of 8.717 QALY. While the final cost in the FNAB-with routine Ctn screening was $4345.04 with a final effectiveness of 8.722 QALY. ICER of routine Ctn screening compared to FNAB-only was $23278.61/QALY (<Willing-To-Pay threshold of $50,000/QALY). Based on sensitivity analyses, Ctn testing is cost-effective if the test cost is less than $236.03.

CONCLUSIONS

Routine Ctn screening is a cost-effective strategy in US if the cost is less than $236.03. Although Ctn screening is not perfect in detecting MTC at early stages, it is a cost-effective alternative of discovering MTC after thyroid lobectomy or on follow-up of a thyroid nodule.

Calcitonin testing for detection of medullary thyroid cancer in people with thyroid nodules

BACKGROUND

Thyroid nodules are very common in general medical practice, but rarely turn out to be a medullary thyroid carcinoma (MTC). Calcitonin is a sensitive tumour marker for the detection of MTC (basal calcitonin). Sometimes a stimulation test is used to improve specificity (stimulated calcitonin). Although the European Thyroid Association's guideline advocates calcitonin determination in people with thyroid nodules, the role of routine calcitonin testing in individuals with thyroid nodules is still questionable.

OBJECTIVES

The objective of this review was to determine the diagnostic accuracy of basal and/or stimulated calcitonin as a triage or add-on test for detection of MTC in people with thyroid nodules.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase and Web of Science from inception to June 2018.

SELECTION CRITERIA

We included all retrospective and prospective cohort studies in which all participants with thyroid nodules had undergone determination of basal calcitonin levels (and stimulated calcitonin, if performed).

DATA COLLECTION AND ANALYSIS

Two review authors independently scanned all retrieved records. We extracted data using a standard data extraction form. We assessed risk of bias and applicability using the QUADAS-2 tool. Using the hierarchical summary receiver operating characteristic (HSROC) model, we estimated summary curves across different thresholds and also obtained summary estimates of sensitivity and specificity at a common threshold when possible.

MAIN RESULTS

In 16 studies, we identified 72,368 participants with nodular thyroid disease in whom routinely calcitonin testing was performed. All included studies performed the calcitonin test as a triage test. Median prevalence of MTC was 0.32%. Sensitivity in these studies ranged between 83% and 100% and specificity ranged between 94% and 100%. An important limitation in 15 of the 16 studies (94%) was the absence of adequate reference standards and follow-up in calcitonin-negative participants. This resulted in a high risk of bias with regard to flow and timing in the methodological quality assessment. At the median specificity of 96.6% from the included studies, the estimated sensitivity (95% confidence interval (CI)) from the summary curve was 99.7% ( 68.8% to 100%). For the median prevalence of MTC of 0.23%, the positive predictive value (PPV) for basal calcitonin testing at a threshold of 10 pg/mL was 7.7% (4.9% to 12.1%). Summary estimates of sensitivity and specificity for the threshold of 10 pg/mL of basal calcitonin testing was 100% (95% CI 99.7 to 100) and 97.2% (95% CI 95.9 to 98.6), respectively. For combined basal and stimulated calcitonin testing, sensitivity ranged between 82% and 100% with specificity between 99% and 100%. The median specificity was 99.8% with an estimated sensitivity of 98.8% (95% CI 65.8 to 100) .

AUTHORS' CONCLUSIONS

Both basal and combined basal and stimulated calcitonin testing have a high sensitivity and specificity. However, this may be an overestimation due to high risk of bias in the use and choice of reference standard The value of routine testing in patients with thyroid nodules remains questionable, due to the low prevalence, which results in a low PPV of basal calcitonin testing. Whether routine calcitonin testing improves prognosis in MTC patients remains unclear.

Calcitonin Screening in Nodular Thyroid Disease: Is There a Definitive Answer?

INTRODUCTION

Calcitonin (Ctn) is a hormone secreted by thyroid "C" cells and is considered an excellent marker for medullary thyroid carcinoma (MTC). However, the use of Ctn to screen patients with nodular thyroid disease (NTD) remains controversial.

OBJECTIVE

The aim of this work was to define the frequency of hypercalcitoninemia among NTD patients followed at a tertiary referral hospital.

METHODS

A retrospective analysis was made of basal Ctn measurements and corresponding patients' records between January 2011 and December 2015. Hypercalcitoninemia was defined as > 10 pg/mL. Depending on the Ctn value, three groups were considered: G1, ≤10 pg/mL; G2, 10-100 pg/mL; G3, ≥100 pg/mL.

RESULTS

Ctn was requested in an NTD context for 1,504 patients, 69 of whom had hypercalcitoninemia. Of these, 20 underwent surgery (G2, 11; G3, 9), and a histological diagnosis of MTC was established in 12 (G2, 3/27%; G3, 9/100%). Surgery was chosen based solely on Ctn levels in 7 cases, since only 5 had a positive cytology.

CONCLUSIONS

Hypercalcitoninemia was found in 4.6% of NTD patients. Ctn levels ≥100 pg/mL were associated with a greater CMT risk than values between 10 and 100 pg/mL, reinforcing results from other groups. The need for an adequate interpretation of results as well as an appropriate selection of patients to surgery stresses the importance of endocrinologists requesting and interpreting results.