Procalcitonin for detecting medullary thyroid carcinoma: a systematic review

Calcitonin levels in autoimmune atrophic gastritis-related hypergastrinemia

PURPOSE

Calcitonin (Ct) is currently the most sensitive biochemical marker of C-cell disease (medullary thyroid cancer [MTC] and C-cell hyperplasia), but its specificity is relatively low. Our aim was to examine whether autoimmune atrophic gastritis (AAG) and chronic hypergastrinemia, with or without chronic autoimmune thyroiditis (AT), are conditions associated with increased Ct levels.

METHODS

Three groups of patients were consecutively enrolled in this  multicentric study: group A consisted of patients with histologically-proven AAG (n = 13; 2 males, 11 females); group B fulfilled the criteria for group A but also had AT (n = 92; 15 males, 77 females); and group C included patients with AT and without AAG (n = 37; 6 males, 31 females).

RESULTS

Median Ct levels did not differ between the three groups. Ct levels were undetectable in: 8/13 cases (61.5%) in group A, 70/92 (76.1%) in group B, and 27/37 (73.0%) in group C. They were detectable but ≤ 10 ng/L in 4/13 (30.8%), 20/92 (21.7%) and 7/37 (18.9%) cases, respectively; and they were > 10 ng/L in 1/13 (7.7%), 2/92 (2.2%) and 3/37 (8.1%) cases, respectively (P = 0.5). Only three patients had high Ct levels (> 10 ng/L) and high gastrin levels and had an MTC. There was no correlation between Ct and gastrin levels (P = 0.353, r = 0.0785).

CONCLUSIONS

High gastrin levels in patients with AAG do not explain any hypercalcitoninemia, regardless of whether patients have AT or not. This makes it mandatory to complete the diagnostic process to rule out MTC in patients with high Ct levels and AAG.

Diagnostic tests for medullary thyroid carcinoma: an umbrella review

PURPOSE

To summarize the more robust evidence about the performance of tools useful for diagnosis of medullary thyroid carcinoma (MTC) such as calcitonin (Ctn) and other circulating markers, ultrasound (US), fine-needle aspiration (FNA), and other imaging procedures.

METHODS

This systematic review of systematic reviews was carried out according to a predefined protocol. A search string was created. An electronical comprehensive search of literature was performed on December 2022. Quality assessment of eligible systematic reviews was performed and main findings were described.

RESULTS

Twenty-three systematic reviews were included and several findings were achieved. Ctn is the most reliable diagnostic marker of MTC with no evidence of improvement with stimulation test. CEA doubling time is more reliable than Ctn in identifying MTC with poorer prognosis. US sensitivity is suboptimal in MTC and only just over half of cases are at high risk according to Thyroid Imaging And Reporting Data Systems. Cytology can correctly detect MTC in just over half of cases and measuring Ctn in washout fluid from FNA is necessary. PET/CT is useful for detecting recurrent MTC.

CONCLUSIONS

Future guidelines of both thyroid nodule management and MTC diagnosis should consider these evidence-based data.

Other markers of medullary thyroid cancer, not only calcitonin

BACKGROUND

Medullary thyroid cancer (MTC) is a rare neuroendocrine tumor originating from parafollicular C-cells. It represents 2% of all thyroid malignancies and 0.4-1.4% of all thyroid nodules. MTC has a variable clinical course, with complete remission often difficult to achieve. An early diagnosis is still crucial in MTC management, enabling a radical surgical treatment, the only chance for curing the patient. Calcitonin (Ct) is a very sensitive MTC tumor marker in patients with thyroid nodules, although Ct-negative MTCs have been described, but not all clinical guidelines recommend the Ct routine measurement in thyroid nodules because of the absolute low prevalence of MTC in the general population and the consequent scarce positive predictive value of Ct. Moreover, the specificity of moderately high Ct levels is not high. Thus, the scientific community has been investigating the possible role of other tumor markers for MTC diagnosis and prognosis.

AIM OF THE REVIEW

The present review is an attempt to summarize the knowledge available today on the role of other serum markers for MTC alternative to Ct.

CONCLUSIONS

At present, literature data does not seem solid enough yet to establish effective flowcharts in evaluating a thyroid nodule for MTC, involving alternative serum markers, particularly in cases of moderately high CT levels. MTC is a rare diagnosis in thyroid nodules, and this makes the evaluation of any tumor serum marker accuracy problematic. More extensive and prospective studies are needed to shed more light on this intriguing challenge.

[111In]In-CP04 as a novel cholecystokinin-2 receptor ligand with theranostic potential in patients with progressive or metastatic medullary thyroid cancer: final results of a GRAN-T-MTC Phase I clinical trial

INTRODUCTION

Medullary thyroid cancer (MTC) is a rare malignant tumour of the parafollicular C-cells with an unpredictable clinical course and currently suboptimal diagnostic and therapeutic options, in particular in advanced disease. Overexpression of cholecystokinin-2 receptors (CCK2R) represents a promising avenue to diagnostic imaging and targeted therapy, ideally through a theranostic approach.

MATERIALS AND METHODS

A translational study (GRAN-T-MTC) conducted through a Phase I multicentre clinical trial of the indium-111 labelled CP04 ([¹¹¹In]In-CP04), a CCK2R-seeking ligand was initiated with the goal of developing a theranostic compound. Patients with proven advanced/metastatic MTC or short calcitonin doubling time were enrolled. A two-step concept was developed through the use of low- and high-peptide mass (10 and 50 μg, respectively) for safety assessment, with the higher peptide mass considered appropriate for therapeutic application. Gelofusine was co-infused in a randomized fashion in the second step for the evaluation of potential reduction of the absorbed dose to the kidneys. Imaging for the purpose of biodistribution, dosimetry evaluation, and diagnostic assessment were performed as well as pre-, peri-, and postprocedural clinical and biochemical assessment.

RESULTS

Sixteen patients were enrolled. No serious adverse events after application of the compound at both peptide amounts were witnessed; transient tachycardia and flushing were observed in two patients. No changes in biochemistry and clinical status were observed on follow-up. Preliminary dosimetry assessment revealed the highest dose to urinary bladder, followed by the kidneys and stomach wall. The effective dose for 200 MBq of [¹¹¹In]In-CP04 was estimated at 7±3 mSv and 7±1 mSv for 10 μg and 50 μg CP04, respectively. Administration of Gelofusine reduced the dose to the kidneys by 53%, resulting in the organ absorbed dose of 0.044±0.019 mSv/MBq. Projected absorbed dose to the kidneys with the use of [¹⁷⁷Lu]Lu-CP04 was estimated at 0.9±0.4 Gy/7.4 GBq. [¹¹¹In]In-CP04 scintigraphy was positive in 13 patients (detection rate of 81%) with superior diagnostic performance over conventional imaging.

CONCLUSION

In the present study, [¹¹¹In]In-CP04 was shown to be a safe and effective radiopharmaceutical with promising theranostic characteristics for patients with advanced MTC.

Medullary thyroid cancer - An update

Medullary thyroid cancer (MTC) is a rare neuroendocrine disease, encompassing about 5% of all thyroid cancers. Due to its peculiar features, this rare tumour offers unique possibilities for translational research studies. It arises from neuroendocrine parafollicular cells in an endocrine organ, and appears as a nodule apparently indistinguishable from thyroid nodules. It has a very peculiar progression with micro metastases difficult to identify, often-remaining stable during years and suddenly undergoing a rapid and unrestrainable progression. Moreover, MTC is one of the neoplasms with the best genetic characterization either in its sporadic or familial form, providing a valuable background to test targeted drugs. In the era of precision medicine, this review aims to give an update on the diagnostic tools, the therapeutic options for advanced MTC, and the most promising opportunities for a personalized follow up.

Incidental diagnosis of medullary thyroid carcinoma due to persistently elevated procalcitonin in a patient with COVID-19 pneumonia: A case report

BACKGROUND

Procalcitonin (Pct) is a common biomarker in clinical practice, especially in the era of coronavirus disease 2019 (COVID-19) infection. Although it is frequently used for the diagnosis and prognostication of bacterial infections or sepsis, it is also elevated in a few other conditions, including medullary thyroid carcinoma (MTC).

CASE SUMMARY

A 43-year-old female presented with moderately severe COVID-19 pneumonia in April 2021. She gradually recovered clinically; however, despite normalization of other inflammatory markers, Pct levels remained persistently elevated. Further workup identified the cause as left lobe MTC with locoregional metastasis. Calcitonin levels were high, and carcinoembryonic antigen levels were normal. The patient underwent total thyroidectomy and neck dissection, which was followed by another radical neck dissection due to residual disease. Currently, she is doing well, nearly having completed her course of external beam radiotherapy with no recurrence. Pct is well documented as a screening tool for MTC, especially because of its stable nature compared to calcitonin in the community settings. It is important to keep in mind the differential diagnosis of MTC in patients with persistently elevated Pct levels despite normal levels of other acute phase reactants. To the best of our knowledge, this is the first report from Asia of such an incidental diagnosis of MTC due to persistently elevated Pct levels in a patient with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

CONCLUSION

Persistently elevated Pct levels can occur in any pro-inflammatory state including infections, sepsis, or acute respiratory distress syndrome. In the current setting, SARS-CoV-2 infection is one such clinical scenario, and in rare situations of persistent elevation, MTC may need to be ruled out.

The correlation between the expression of ATF4 and procalcitonin combined with the detection of RET mutation and the pathological stage and clinical prognosis of medullary thyroid carcinoma

To explore the correlation between the activating transcription factor 4 (ATF4) and procalcitonin (PCT) expressions combined with RET mutation and the pathological staging and clinical prognosis of sporadic medullary thyroid carcinoma (SMTC). Fifty cases (tumor tissue) of SMTC diagnosed by clinicopathology were collected and the patients with nodular goiter were selected as normal control. The RET mutation site was analyzed by detection kit and expressions of PCT and ATF4 in SMTC were analyzed by Western blot and immunohistochemistry. Multiple linear regression was used to analyze the correlation of risk factors (PCT or ATF4 expression, RET mutation, tumor differentiation, SMTC stage, lymphatic metastasis) for 5-year recurrence and survival of SMTC. The ATF4 and PCT expressions were significantly decreased and increased, respectively, with the increase of the SMTC stage. The most frequent mutation of RET gene in cancer tissue was M 22458A in exon 16. The ATF4 and PCT expressions, as well as RET mutation, were significantly associated with a 5-year recurrence, while the ATF4 expression was significantly related to better 5-year survival. ATF4 and PCT expressions combined with RET mutation are related to the clinical prognosis of SMTC and can predict SMTC staging.

Procalcitonin as an Alternative Tumor Marker of Medullary Thyroid Carcinoma

CONTEXT

Calcitonin (CT) measurement is pivotal in the management of medullary thyroid carcinoma (MTC), but several pitfalls can affect its reliability. Procalcitonin (ProCT) has been reported as a promising alternative MTC tumor marker.

OBJECTIVE

This study aimed to determine the ProCT diagnostic accuracy in prediction and treatment monitoring of MTC.

METHODS

Electronic databases were searched for observational studies published until May 2021 without language or time restrictions. Studies comparing ProCT and calcitonin accuracy were included. After removing duplicates and exclusion of not-eligible articles, relevant articles were screened independently by 2 reviewers. Eleven studies (4.5% of the identified studies) met the selection criteria. Two reviewers independently extracted data and assessed data quality and validity through QUADAS-2.

RESULTS

A meta-analysis was performed on 11 sufficiently clinically and statistically homogeneous studies (n = 5817 patients, 335 MTC patients). Hierarchical summary receiver operating characteristics and bivariate methods were applied. Serum ProCT was found to be a highly accurate test for MTC diagnosis and monitoring. The pooled sensitivity, specificity, positive and negative likelihood ratios, area under the curve, and positive and negative predictive values for ProCT were 0.90 (95% CI: 0.71-0.97), 1.00 (95% CI: 0.85-1.00), 288 (95% CI: 5.6-14 929.3), 0.10 (95% CI: 0.03-0.33), 0.97 (95% CI: 0.95-0.98), 99%, and 2%, respectively.

CONCLUSIONS

The high accuracy, compounded with favorable analytical characteristics, give ProCT great potential to replace calcitonin as a new standard of care in the management of MTC.

Persistence of Elevated Procalcitonin in a Patient with Coronavirus Disease 2019 Uncovered a Diagnosis of Medullary Thyroid Carcinoma

Objective

During the ongoing coronavirus disease 2019 pandemic, procalcitonin (PCT) levels have proven useful in assisting clinicians to diagnose bacterial superinfection. However, in the absence of signs of infection or at the resolution thereof, inappropriately and persistently high PCT levels may suggest and reveal the presence of other pathologies. We report a patient with severe acute respiratory syndrome coronavirus 2 pneumonia with initially elevated PCT levels that persisted during recovery, prompting the diagnosis of medullary thyroid carcinoma (MTC).

Methods

A 43-year-old man presented with a 2-day history of fever, sneezing, sore throat, and dry cough. His PCT was 94 ng/mL (normal value, 0.00-0.10 ng/mL), and he was positive for severe acute respiratory syndrome coronavirus 2 RNA.

Results

Empirical antibiotic therapy was administered for 7 days, but despite a clinical improvement, serum PCT remained high (84 ng/mL). Serum calcitonin (CTN) was 2120 pg/mL (normal, ≤12 pg/mL). Cytologic examination of thyroid nodules and CTN measurement of the aspiration needle washout confirmed MTC. The patient underwent total thyroidectomy with bilateral cervical lymph node dissection. Lowered CTN (986 pg/mL) and PCT (16 ng/mL) levels were observed 48 hours after surgery. A close follow-up was planned following the results of RET gene analysis.

Conclusion

PCT can be a useful biochemical marker of MTC suspicion in patients with inflammatory conditions and persistently elevated PCT, even after resolution. In our case, high levels of PCT in a patient with coronavirus disease 2019 pneumonia without signs of bacterial infection led to MTC diagnosis.

Immunohistochemical detection of procalcitonin in fibrolamellar hepatocellular carcinoma

A 25-year-old woman with fever and epigastric pain was referred to our hospital. Blood examination showed significant liver dysfunction, markedly high C-reactive protein (CRP 19.1 mg/dL) and procalcitonin (48.3 ng/mL) levels. Dynamic computed tomography showed a tumor approximately 120 mm in size in the right lobe of the liver, but with no abscess formation. The patient was hospitalized and started on antibiotics; her CRP level improved, but the procalcitonin level did not decrease. Histopathological examination of the liver tumor biopsy revealed fibrolamellar hepatocellular carcinoma (FLC). Positive staining of the FLC with an anti-procalcitonin antibody suggested the production of procalcitonin.

Medullary thyroid carcinoma: recent advances in identification, treatment, and prognosis

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor that represents <5% of all thyroid malignancies and is generally more aggressive than differentiated thyroid cancer. The aim of this study is to provide an update, through review of clinical studies of patients with MTC published between January 1, 2016, and June 1, 2021, on recent advances in the diagnosis and treatment of MTC. This review focuses on updates in biochemical testing, imaging, hereditary disease, surgical management, adjuvant therapies, and prognosis. Recent advances reviewed herein have sought to diagnose MTC at earlier stages of disease, predict when patients with a hereditary syndrome may develop MTC, use functional imaging to assess for distant metastases, perform optimal initial surgery with appropriate lymphadenectomy, employ targeted systemic therapies for patients with progressive metastatic disease, and better predict patient-specific outcomes.

Basal and Calcium-Stimulated Procalcitonin for the Diagnosis of Medullary Thyroid Cancers: Lights and Shadows

BACKGROUND

Procalcitonin (proCt) was recently proposed as an alternative or in addition to calcitonin (Ct) in medullary thyroid cancer (MTC) diagnostics.

METHODS

Serum basal Ct (bCt) and proCt (bproCt) levels were measured before surgery from a consecutive series of patients with (n=43) and without (n=75) MTC, retrospectively collected in Padua. Serum bproCt, bCt and stimulated proCt and Ct (sproCt and sCt) were measured in another consecutive series of 33 patients seen at three tertiary-level institutions undergoing a calcium stimulation test prior to surgery, 20 of them with a final diagnosis of MTC, and 13 with non-MTC nodular disease.

RESULTS

Median bproCt levels were higher in MTC than in non-MTC. A positive correlation was found for bproCt with bCt (P<0.01, R² = 0.75), and with tumor size (P<0.01, R² = 0.39). The cut-off for bproCt differentiating between MTC and non-MTC patients was >0.07 ng/ml (sensitivity: 85.7%, specificity: 98.9%, positive predictive value [PPV]: 98.2%, negative predictive value [NPV]: 90.6%, P<0.01). While bproCt was >0.07 ng/ml in 38/39 (97.4%) patients with MTC >10 mm, it was above said cut-off only in 15/23 (65.2%) patients with tumors ≤10 mm. A sproCt >0.19 ng/ml was able to identify MTC [sensitivity: 90.0%, specificity:100.0%, PPV: 100.0%, NPV: 86.7% (P<0.01)].

CONCLUSIONS

Our data suggest that bproCt can be a good adjunct to Ct for MTC diagnostic purposes. In consideration of its high specificity, it can be used in combination with Ct in MTC diagnostics, particularly in the case of mildly elevated basal Ct levels.

Clinical relevance of 18F-FDG PET/CT in the postoperative follow-up of patients with history of medullary thyroid cancer

BACKGROUND

The aim of the study was evaluation of 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography with computed tomography (PET/CT) in the detection of active disease in the patients with suspected recurrence of the medullary thyroid carcinoma (MTC).

PATIENTS AND METHODS

18F-FDG PET/CT investigation was performed in 67 patients, investigated from 2010 to 2019. _ Follow up was performed from 6 to 116 months after surgery (median 16.5 months, x± SD = 29±28.9 months). Twenty five of 67 patients underwent 99mTc-dimercaptosuccinic acid (99mTc-DMSA) scintigraphy, 11 underwent somatostatin receptor scintigraphy (SRS) with 99mTc-HYNIC TOC while 11 123I-metaiodobenzylguanidine (MIBG) scintigraphy.

RESULTS

From 67 patients, 35 (52.2%) had true positive 18F-FDG PET/CT findings (TP). Average maximal standardized uptake value (SUVmax) for all TP lesions was 5.01+3.6. In 25 (37.3%) patients findings were true negative (TN). Four (6%) patients had false positive (FP) findings while three (4.5%) were false negative (FN). Thus, sensitivity of the 18F-FDG PET/ CT was 92.11%, specificity 86.21%, positive predictive value 89.74%, negative predictive value 89.29% and accuracy 89.55%. In 27 patients (40%) 18F-FDG PET/CT finding influenced further management of the patient.

CONCLUSIONS

18F-FDG PET/CT has high accuracy in the detection of metastases/recurrences of MTC in patients after thyroidectomy as well as in evaluation and the appropriate choice of the therapy.

Elevated procalcitonin levels in primary hepatic neuroendocrine carcinoma: Case report and literature review

RATIONALE

Procalcitonin (PCT) has been identified as a tumor biomarker in medullary thyroid carcinoma. Other neuroendocrine carcinomas with elevated PCT levels are relatively rare, and are mainly reported in the lung, digestive tract, and pancreas. No studies in the literature have reported a case of primary hepatic carcinoma complicated with unexpectedly elevated PCT levels.

PATIENT CONCERNS

A 78-year-old man with persistent fatigue and mild fever was complicated with an extremely high PCT level. Radiological examination revealed a single hypodense lesion in the left lobe of the liver with a "rapid enhancement and rapid washout" pattern. Pathological analysis showed a poorly differentiated neuroendocrine carcinoma (grade 3) with multiple genetic mutations.

DIAGNOSIS

Primary hepatic neuroendocrine carcinoma.

INTERVENTIONS

The patient received antibiotic therapy and subsequent transcatheter hepatic arterial chemoembolization; a PCT assessment and computed tomography were performed during the follow-up.

OUTCOMES

The PCT level did not decline after antibiotic therapy but greatly declined in response to effective transcatheter hepatic arterial chemoembolization. The patient survived and is still being followed up.

LESSONS

An extremely elevated PCT level may raise a suspicion of a neuroendocrine carcinoma and plays an indicative role as a biomarker during therapy.

Diagnostic Challenges and Laboratory Considerations for Pediatric Sepsis

Background

Sepsis is a leading cause of death for children in the US and worldwide. There is a lack of consensus how sepsis is clinically defined, and sepsis definitions and diagnostic guidelines for the pediatric population have remained unchanged for more than a decade now. Current pediatric definitions are largely based on adult guidelines and expert opinion rather than evidence based on outcomes in the pediatric populations. Without a clear definition of sepsis, it is challenging to evaluate the performance of new laboratory tests on the diagnosis and management of sepsis.

Content

This review provides an overview of common etiologies of sepsis in pediatric populations, challenges in defining and diagnosing pediatric sepsis, and current laboratory tests used to identify and monitor sepsis. Strengths and limitations of emerging diagnostic strategies will also be discussed.

Summary

Currently there is no single biomarker that can accurately diagnose or predict sepsis. Current biomarkers such as C-reactive protein and lactate are neither sensitive nor specific for diagnosing sepsis. New biomarkers and rapid pathogen identification assays are much needed. Procalcitonin, although having some limitations, has emerged as a biomarker with demonstrated utility in management of sepsis in adults. Parallel studies analyzing the utility of procalcitonin in pediatric populations are lagging but have shown potential to affect sepsis care in pediatric populations. Multibiomarker approaches and stepwise algorithms show promise in the management of pediatric sepsis. However, a major hurdle is the lack of validated clinical criteria for classification of pediatric sepsis, which is necessary for the development of well-designed studies that can assess the clinical impact of these emerging biomarkers.

Procalcitonin as a marker of Gram-negative bloodstream infections in hematological patients with febrile neutropenia

The aim of this study was to explore the predictive value of procalcitonin (PCT) in Gram-negative bloodstream infections (BSIs) in hematological patients with febrile neutropenia. A total of 1466 samples (396 blood culture (BC)-positive, 1052 BC-negative, and 18 contaminated specimens) were included, comprising 268 Gram-negative, 88 Gram-positive, 19 fungal, and 21 polymicrobial BSIs. Median PCT value (0.72 ng/mL; IQR: 0.23-3.87) was significantly higher in Gram-negative than Gram-positive (0.34 ng/mL; IQR: 0.14-2.23; p < .01), or fungal (0.27 ng/mL; IQR: 0.13-0.40; p < .01) BSIs. In mono-microbial BSIs, the best PCT cutoff distinguishing Gram-negative BSIs from all other fever causes was 0.56 ng/ml, with a specificity of 76.8%. PCT levels were significantly higher in BSIs from multidrug-resistant (MDR) Gram-negative strains than from non-MDR (p < .01). This study confirms that elevated PCT may predict Gram-negative BSIs in hematological patients with febrile neutropenia, and demonstrates higher PCT levels in MDR Gram-negative BSIs in these patients.

Laboratory Testing in Thyroid Conditions - Pitfalls and Clinical Utility

Thyroid disorders are common, affecting more than 10% of people in the US, and laboratory tests are integral in the management of these conditions. The repertoire of thyroid tests includes blood tests for thyroid-stimulating hormone (TSH), free thyroxine, free triiodothyronine, thyroglobulin (Tg), thyroglobulin antibodies (Tg-Ab), thyroid peroxidase antibodies (TPO-Ab), TSH receptor antibodies (TRAb), and calcitonin. TSH and free thyroid hormone tests are frequently used to assess the functional status of the thyroid. TPO-Ab and TRAb tests are used to diagnose Hashimoto's thyroiditis and Graves' disease, respectively. Tg and calcitonin are important tumor markers used in the management of differentiated thyroid carcinoma and medullary thyroid carcinoma (MTC), respectively. Procalcitonin may replace calcitonin as a biomarker for MTC. Apart from understanding normal thyroid physiology, it is important to be familiar with the possible pitfalls and caveats in the use of these tests so that they can be interpreted properly and accurately. When results are discordant, clinicians and laboratorians should be mindful of possible assay interferences and/or the effects of concurrent medications. In addition, thyroid function may appear abnormal in the absence of actual thyroid dysfunction during pregnancy and in critical illness. Hence, it is important to consider the clinical context when interpreting results. This review aims to describe the above-mentioned blood tests used in the diagnosis and management of thyroid disorders, as well as the pitfalls in their interpretation. With due knowledge and care, clinicians and laboratorians will be able to fully appreciate the clinical utility of these important laboratory tests.

Procalcitonin measurement to screen medullary thyroid carcinoma: A prospective evaluation in a series of 2705 patients with thyroid nodules

BACKGROUND

To prospectively evaluate the role of procalcitonin (PCT) in screening of patients with thyroid nodules for medullary thyroid carcinoma (MTC).

MATERIALS AND METHODS

We measured PCT in 2705 patients with thyroid nodules referred to our centre between January 2011 and December 2017. Those with a positive PCT were operated after positive confirmatory tests such as fine-needle aspiration, measurement of calcitonin (CT) in serum and fine-needle aspiration washouts or CT stimulation testing. Patients with a negative PCT were operated based on the results of further diagnostics. The diagnostic performance of PCT was evaluated, and the best cut-off level was selected by ROC curve analysis.

RESULTS

Among 2705 patients, 9 with positive serum PCT (ie, above 0.1 μg/L) and 370 with negative PCT underwent thyroid surgery. MTC was histologically confirmed in all patients with positive PCT but not found in patients with negative PCT. Serum PCT levels were significantly higher in patients with MTC (median 0.64 μg/L, range 0.16-12.9 μg/L) than in those without (median 0.075 μg/L, range 0.075-0.16 μg/L; P < .0001). ROC curves were plotted to calculate the optimal PCT value separating patients with MTC from those without. The best cut-off was 0.155 μg/L with sensitivity, specificity, positive and negative predictive values as well as accuracy of 100%, 99.7%, 91.7%, 100% and 99.7%, respectively. Positive and negative likelihood ratios were 329 and zero, respectively.

CONCLUSIONS

Measurement of PCT is a sensitive and accurate method for detecting MTC in patients with thyroid nodules and can thus be a reliable alternative to CT measurement.

Procalcitonin as Marker of Recurrent Medullary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Calcitonin measurement is pivotal in the management of medullary thyroid carcinoma (MTC), but several pitfalls can affect its reliability. Other potential markers have been proposed, and procalcitonin (ProCT) has been reported as promising. The present study was undertaken to summarize the published data and provide more robust estimates on the reliability of ProCT as marker in the management of patients with MTC.

METHODS

The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The sources comprised studies published through May 2018. Journal Articles that reported series of MTC patients undergone ProCT during postoperative follow-up were searched. A random-effects model was used for statistical pooling of the data. The I² index was used to quantify the consistency among the studies. The Egger test evaluated the possible presence of significant publication bias. Quality assessment of the studies was performed according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

RESULTS

According to inclusion and exclusion criteria five papers, reporting 296 MTC patients undergone ProCT evaluation, were finally selected. The number of MTC with recurrence was 140. The pooled sensitivity of ProCT in detecting recurrence was 96% (95% confidence interval [CI], 92% to 99%), with neither heterogeneity (I²=0%) nor publication bias (Egger test, 3.16; P=0.99). The pooled specificity was 96% (95% CI, 87% to 100%) with mild heterogeneity (I²=66.6%), while Egger test was not calculable.

CONCLUSION

The present meta-analysis provides evidence that ProCT is reliable to manage MTC patients during their postoperative follow-up.

Procalcitonin as a postoperative marker in the follow-up of patients affected by medullary thyroid carcinoma

AIM

Due to the limits of calcitonin, other markers are warranted to better manage medullary thyroid carcinoma patients, and procalcitonin has been reported as promising. Here we aimed to evaluate procalcitonin as a marker of medullary thyroid carcinoma in the post-treatment follow-up.

METHODS

Medullary thyroid carcinoma patients previously treated by thyroidectomy were enrolled. After complete imaging work-up (i.e. ultrasonography, computed tomography, magnetic resonance and ¹⁸FDG-PET-CT) we identified patients with structural recurrent/persistent medullary thyroid carcinoma (active medullary thyroid carcinoma) and subjects with no evidence of disease. Then, both calcitonin and procalcitonin were measured and their performance analyzed.

RESULTS

The final series included 55 medullary thyroid carcinoma patients treated and followed-up for about five years. Of these, 43 were assessed as no evidence of disease, and 12 as active medullary thyroid carcinoma. The median value of procalcitonin was significantly higher ( P < 0.0001) in active medullary thyroid carcinoma patients (3.10 ng/mL) than in those with no evidence of disease (0.10 ng/mL). Also, calcitonin levels of active medullary thyroid carcinoma (96.7 pg/mL) were significantly ( P < 0.0001) higher than that of no evidence of disease (2.0 pg/mL). At the receiver operating characteristic curve analysis, the optimal cut-off of procalcitonin was ≥0.32 ng/mL with 92% sensitivity and 98% specificity, while the most accurate threshold of calcitonin was ≥12.0 pg/mL with 100% sensitivity and 91% specificity. There was no active medullary thyroid carcinoma with simultaneously negative results of procalcitonin and calcitonin.

CONCLUSIONS

Procalcitonin is reliable in discriminating medullary thyroid carcinoma patients with active disease from those with no evidence of disease. We suggest using procalcitonin as complementary to calcitonin to follow-up medullary thyroid carcinoma patients.

Diagnostic and predictive values of procalcitonin in bloodstream infections for nosocomial pneumonia

PURPOSE

We evaluated the diagnostic accuracy of PCT to distinguish between gram-negative (GN) and gram-positive (GP) bloodstream infections nosocomial pneumonia (NP) patients and compared PCT levels with the pneumonia severity index (PSI) for predicting mortality.

METHODS

Data were collected retrospectively for blood culture-positive NP patients between January 2014 and August 2016. PCT levels were compared between patients with GN versus GP infections. Outcome variables included 28- and 60-day mortality.

RESULTS

PCT level was higher in GN infections than in GP infections. PCT could differentiate between GN and GP infections with an AUC value of 0.706. At a PCT cutoff of 5.4 ng/mL, the specificity for GN infections were 80.3%. The AUCs for 28- and 60-day mortality were 0.758 and 0.759 for PSI, and 0.620 and 0.634 for PCT. Serum PCT level was less predictive of mortality in GN NP patients compared with that for GP NP patients. There was a significantly positive correlation between PCT and PSI, and the correlation in GP NP patients was better than that in GN NP patients.

CONCLUSIONS

PCT could differentiate between GN and GP bloodstream infections in patients with NP. However, PCT levels were less predictive of mortality compared with the PSI.

Do you want to participate in a clinical study as a healthy control? - Risk or benefit?

A healthy woman volunteered to participate as “healthy control” in a study. An increased level of procalcitonin (PCT) was detected and remained elevated on follow-up measurements. As calcitonin levels were elevated as well, thyroid ultrasound was performed which revealed nodes in both thyroid lobes, one of them showing metabolic activity in positron emission tomography-computed tomography scan. To exclude a malignant thyroid cancer despite the negative findings in a fine needle aspiration the patient underwent thyroidectomy and a medullary thyroid carcinoma (MTC) was detected in the right lobe. MTC is a rare endocrine tumor with a poor prognosis once having spread, therefore early detection remains a priority for the outcome. Screening parameter is serum calcitonin, in absence of infection the pro-hormone PCT can be used as a screening parameter as well with high sensitivity.

The role of elevated serum procalcitonin in neuroendocrine neoplasms of digestive system

INTRODUCTION

Elevated serum procalcitonin (PCT) was reported in patients with certain type of neuroendocrine neoplasms (NENs).

OBJECTIVE

The aim of this study was to assess the role of elevated serum PCT in NENs from digestive system.

PATIENTS AND METHODS

Serum PCT and serum CgA level were measured in 155 patients with NENs from digestive system.

RESULTS

Elevated serum PCT was found in 63 patients (40.6%). Grade 3 disease was a significant factor associated with elevated serum PCT (OR, 9.24; 95%CI, 3.04-28.08; P<0.001). Serum PCT level was significantly decreased after treatment both in patients with stable disease (P=0.003) and patients with partial remission (P=0.001). In these patients, serum PCT level significantly increased again at the time of progression disease (P=0.001). Elevated serum PCT was a significant factor of worse survival (HR, 2.86; 95%CI, 1.36-6.03; P=0.006). Compared with patients with normal serum PCT and CgA level, patients with either PCT or CgA elevated and patients with both PCT and CgA elevated had progressively worse survival. Additionally, PCT expression in tumor cells was found in 24.0% of patients but did not correlate with other clinicopathological factors, including serum PCT.

CONCLUSIONS

Serum PCT is elevated in part of patients with NENs of digestive system, especially in patients with grade 3 disease. Serum PCT level can help evaluate treatment response and its elevation indicates poor prognosis. Combination of serum PCT and CgA can improve outcome prediction.

Differential Diagnosis in Neuroendocrine Neoplasms of the Larynx

The differential diagnosis of neuroendocrine neoplasms of the larynx is broad and includes lesions of epithelial, mesenchymal, and neuroectodermal origin. These lesions have overlapping clinical and pathologic aspects and must be carefully considered in the differential diagnosis of laryngeal neoplasms. The prognosis and treatment are also different among these tumor types, which necessitates making these distinctions clinically. The current literature was reviewed to provide updated information regarding the epithelial-derived tumors, including carcinoid, atypical carcinoid, small cell neuroendocrine carcinomas, large cell neuroendocrine carcinoma, and squamous cell carcinoma with neuroendocrine component. These tumors are compared and contrasted with non-epithelial-derived tumors such as paraganglioma and nonmucosal tumors, such as medullary thyroid carcinoma. The morphologic and cytologic features are discussed, along with helpful immunohistochemical and ancillary investigations.

Nodular Thyroid Disease and Thyroid Cancer in the Era of Precision Medicine

The management of thyroid nodules, one of the main clinical challenges in endocrine clinical practice, is usually straightforward. Although the most important concern is ruling out malignancy, there are grey areas where uncertainty is frequently present: the nodules labelled as indeterminate by cytology and the extent of therapy when thyroid cancer is diagnosed pathologically. There is evidence that the current available precision medicine tools (from all the "-omics" to molecular analysis, fine-tuning imaging or artificial intelligence) may help to fill present gaps in the future. We present here a commentary on some of the current challenges faced by endocrinologists in the field of thyroid nodules and cancer, and illustrate how precision medicine may improve their diagnostic and therapeutic capabilities in the future.

Calcitonin measurement and immunoassay interference: a case report and literature review

Calcitonin (CT) is currently the most sensitive serological marker of C-cell disease [medullary thyroid carcinoma (MTC) and C-cell hyperplasia]. Starting with a report on a case that occurred at our institution, this review focuses on trying to explain the reasons behind the poor specificity and sensitivity of the various CT immunoassays. A 15-year-old patient was referred to our institution in May 2014 for moderately elevated CT levels. Thyroid ultrasonography (US) documented a colloidal goiter. Secondary causes of the hypercalcitoninemia (hyperCT) were ruled out. The mismatch between the clinical picture and the laboratory results prompted us to search for other reasons for the patient's high CT levels, so we applied the heterophilic blocking tube (HBT) procedure to the patient's sera before the CT assay. Using this pretreatment step, his serum CT concentration dropped to <1 ng/L, as measured at the same laboratory. Measuring plasma CT has an important role in screening for C-cell disease, but moderately elevated serum CT levels need to be placed in their clinical context, bearing in mind all the secondary causes of C-cell hyperplasia and the possibility of laboratory interference, before exposing patients to the risks and costs of further tests.

Utility of proGRP as a tumor marker in the medullary thyroid carcinoma

Background:

Medullary thyroid carcinoma (MTC) is a neuroendocrine tumor caused by a malignant transformation in the parafollicular C-cells of the thyroid, where calcitonin (CT) is released. Nowadays the main tumor markers (TM) used in the diagnosis and follow-up of MTC patients are CT and carcinoembryonic antigen (CEA). Nonetheless, progastrin releasing peptide (proGRP) has been recently proposed as a TM useful in the MTC. Our aims were to investigate the release of proGRP in thyroid tumors, its role in the assessment of advanced MTC and its utility in the differential diagnosis between MTC and non-MTC thyroid tumors.

Methods:

Serum samples from 22 patients with MTC and 16 with non-MTC were collected. Patients were classified into advanced cancer or no evidence of disease (NED). ProGRP was performed by Architect (Abbot Diagnostics), CT by Liaison (Diasorin) and CEA by Cobas E601(Roche Diagnostics).

Results:

ProGRP median concentration in advanced MTC was significantly higher (1398.4 pg/mL) when compared with non-MTC, either in advanced disease (24.9 pg/mL) or NED (14.6 pg/mL). In non-MTC patients, proGRP median concentration was below its cutoff level (50 pg/mL). Similar to CT, proGRP was able to detect 88.9% of MTC patients, but with a slightly lower specificity of 76.9%. Using proGRP together with CT the sensitivity increased to 100%.

Conclusions:

The low prevalence of this malignancy strongly recommends further collaborative studies, mainly focused on monitoring proGRP during tyrosine kinase inhibitors treatment for early detection of resistance and assessing its usefulness to avoid the observed false positive fluctuations that occur with CT and CEA.

Procalcitonin levels in bloodstream infections caused by different sources and species of bacteria

OBJECTIVE

The aim of this study was to evaluate procalcitonin (PCT) diagnostic accuracy in discriminating gram-negative (GN) from gram-positive (GP) bloodstream infections and determining the relationship between PCT levels, infection sites, and pathogen types.

METHODS

Clinical and laboratory data were collected from patients with blood culture (BC)-positive sepsis between January 2014 and December 2015. PCT levels at different infection sites were compared, as was the presence of GN and GP bloodstream infection. A receiver operating characteristic (ROC) curve was generated to assess diagnostic accuracy.

RESULTS

Of the 486 monomicrobial BCs, 254 (52.26%) were positive for GN bacteria (GNB), and 202 (42.18%) for GP bacteria (GPB). Median PCT levels were higher in BCs positive for GN (2.42ng/ml, IQR: 0.38-15.52) than in those positive for GPB (0.49ng/ml, IQR: 0.13-5.89) (P<0.001). In the ROC analysis to differentiate between GNB and GPB, the area under the curve was 0.628 (95% CI: 0.576-0.679). When the cutoffs for PCT were 10.335 and 15.000ng/ml, the specificity of GNB infection was 80.2% and 84.2%, respectively. PCT levels caused by GNB differed between Escherichia coli and Acinetobacter baumanni/Burkholderia cepacia, Klebsiella pneumonia and Acinetobacter baumanni. PCT levels caused by GPB differed between Staphylococcus epidermidis/Staphylococcus aureus and Staphylococcus hominis/Staphylococcus haemolyticus, Enterococcus faecium and Enterococcus faecalis/S.hominis/S. haemolyticus. Among patients with known infection sites, there were statistical differences in PCT levels between abdominal infection and pneumonia/infective endocarditis, urinary tract infection and pneumonia/catheter-related infection/infective endocarditis.

CONCLUSION

PCT can distinguish between GNB and GPB infection, as well as between different bacterial species and infection sites.

Management of hereditary medullary thyroid carcinoma

Hereditary medullary thyroid carcinoma (MTC) represents up to one-third of MTC cases and includes multiple endocrine neoplasia syndrome type 2A (and its variant familial MTC) and 2B. The aim of this paper is to provide an overview of the disease focusing on the management of hereditary MTC patients, who have already developed tumor, as well as discuss the recommended approach for asymptomatic family members carrying the same mutation. A PubMed search was performed to review recent literature on diagnosis, genetic testing, and surgical and medical management of hereditary MTC. The wide use of genetic testing for RET mutations has markedly influenced the course of hereditary MTC. Prophylactic thyroidectomy of RET carriers at an early age eliminates the risk of developing MTC later in life. Pre-operative staging is a strong prognostic factor in patients, who have developed MTC. The use of recently approved tyrosine kinase inhibitors (vandetanib, cabozantinib) holds promising results for the treatment of unresectable, locally advanced, and progressive metastatic MTC. Genetic testing of the RET gene is a powerful tool in the diagnosis and prognosis of MTC. Ongoing research is expected to add novel treatment options for patients with advanced, progressive disease.

A Genomic Alternative to Identify Medullary Thyroid Cancer Preoperatively in Thyroid Nodules with Indeterminate Cytology

BACKGROUND

The use of calcitonin screening for the rare medullary thyroid cancer (MTC) is controversial due to questions of efficacy, accuracy, and cost-effectiveness. This study reports the results of a large prospective validation using a machine-trained algorithm (MTC Classifier) to preoperatively identify MTC in fine-needle aspiration biopsies in lieu of calcitonin measurements.

METHODS

Cytology analysis on a prospective consecutive series of 50,430 thyroid nodule biopsies yielded a total of 7815 indeterminate (Bethesda categories III/IV) cases, which were tested with the MTC classifier. A prospective, consecutively submitted series of 2673 Bethesda III-VI cases with cytology determined locally was also evaluated. RNA was isolated and tested for the MTC Classifier using microarrays.

RESULTS

Forty-three cases were positive by the MTC Classifier among 10,488 tested nodules (0.4%), consistent with the low prevalence of MTC. Of these, all but one was histologically or biochemically confirmed as MTC, yielding a positive predictive value (PPV) of 98%. Of the positive cases, only 19 (44%) had been specifically suspected of MTC by cytology, highlighting the limitations of light microscopy to detect this disease. Three surgically confirmed MTC cases that were detected by the MTC Classifier had low basal serum calcitonin values, indicating these would have been missed by traditional calcitonin screening methods. A pooled analysis of three independent validation sets demonstrates high test sensitivity (97.9%), specificity (99.8%), PPV (97.9%), and negative predictive value (99.8%).

CONCLUSIONS

A clinical paradigm is proposed, whereby cytologically indeterminate thyroid nodules being tested for common malignancies using gene expression can be simultaneously tested for MTC using the same genomic assay at no added cost.

Serum Markers Measured in FNA Fluids of Medullary Thyroid Carcinoma Occurring as a Cyst

Background

Diagnosis of medullary thyroid carcinoma (MTC) is still a challenge, and the measurement of calcitonin in fine-needle aspiration (FNA) washout has been recently introduced. Rarely, MTC presents as a cyst and its preoperative detection is difficult.

Methods

A 66-year-old woman was referred to us with high serum calcitonin. Ultrasound evaluation showed one cystic and one solid nodule. FNA was performed in both nodules and calcitonin, procalcitonin and CEA were measured in the aspirate fluids.

Results

The markers showed elevated levels in the FNA washout of the cyst and the patient was operated on. Final histology demonstrated MTC of the cystic nodule. Four weeks later, all serum markers were undetectable.

Conclusions

In the presence of a cystic thyroid lesion the diagnosis of MTC should be taken into account, and measuring calcitonin in FNA fluid is relevant. The determination in FNA of other markers is technically feasible but its role should be evaluated in larger series.