Comparison of serum calcitonin and procalcitonin in detecting medullary thyroid carcinoma among patients with thyroid nodules

Serum Biochemical Markers for Medullary Thyroid Carcinoma: An Update

Introduction

Medullary thyroid carcinoma (MTC), a rare malignancy, requires early diagnosis for optimal patient outcomes. An important aspect of MTC diagnosis is the assessment of serum biomarkers. This review aimed to evaluate the use of serum biomarkers in the diagnosis, prognosis, and follow-up of MTC.

Methods

A thorough search of PubMed covering 1975 to 2022 was conducted to identify English-language articles on MTC serum biomarkers.

Results

The review revealed that calcitonin (Ctn) and carcinoembryonic antigen (CEA) remain the most important serum biomarkers for MTC diagnosis and management. Despite limited studies on procalcitonin (PCT), its stability and ability to exclude interference from inflammation make it a valuable potential marker of MTC. Although the positive rate of serum CA19-9 levels in MTC patients was not high, it can be used as an indicator of poor prognosis in advanced MTC. Other serum markers, including chromogranin A, gastrin-releasing peptide precursor, and neurospecific enolase, did not show any unique value in MTC diagnosis and management.

Conclusion

Taken together, this review emphasized the importance of serum biomarkers, particularly Ctn and CEA, in the diagnosis and management of MTC. PCT shows promise as a valuable potential marker, whereas CA19-9 can be used as a prognostic indicator of advanced MTC. Further research is needed to validate the significance of these serum biomarkers in MTC and determine the effects of confounding factors on their levels. Clinicians should consider using these markers in MTC diagnosis, prognosis, and follow-up, particularly for patients with advanced disease.

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.

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.

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.

Evolution of thyroid cancer biomarkers: from laboratory test to patients’ clinical management

Over the past three decades, laboratory medicine has significantly evolved thanks to technological advances made possible by new materials and evidence. Clinicians’ ongoing requests for powerful, rapid, and minimally invasive tests has led manufacturers to develop rapid, accurate, and sensitive tests that can increase diagnostic accuracy and improve follow-up, bringing laboratory medicine ever closer to personalized medicine. The aim of this study was to critically review the main problems of the current Tg and CT biomarkers for the diagnosis/monitoring of DTC and MTC, respectively, and to identify the advantages and challenges of using the new laboratory biomarkers in the clinical management of patients with differentiated and medullary thyroid cancer. Insufficient harmonization of Tg and CT assays and lack of interchangeability of laboratory results and cutoff values pose challenges for comparability and standardization of procedures and methods. New diagnostic and monitoring approaches such as PCT or the Tg doubling time have proven to be effective. Close collaboration between clinicians and laboratory specialists remains essential to translate the advantages and limitations of current assays into appropriate clinical interpretation criteria. Over the years, the journal Clinical Chemistry and Laboratory Medicine (CCLM) has taken many steps to develop advanced research and technology in the diagnosis and monitoring of tumor cancer and to help clinicians translate it into clinical practice.

Diagnostic Utility of Procalcitonin for Sporadic Medullary Thyroid Carcinoma in Patients with Nodular Disease and Mild or Moderate Hypercalcitoninemia

Many authors recommend the measurement of serum calcitonin (Ctn) to screen for sporadic medullary thyroid carcinoma (MTC) in patients with thyroid nodules. In this situation, procalcitonin (pro-Ctn) would have greater utility in patients with hypercalcitoninemia<100 pg/ml. The aim of this study was to evaluate the utility of pro-Ctn in patients with thyroid nodules and without a suspicion of familial MTC or type 2 multiple endocrine neoplasia who had mild or moderate hypercalcitoninemia without an apparent cause. Consecutive patients with nodular thyroid disease assessed routinely by Ctn measurement were selected. Sixty patients with basal Ctn>10 pg/ml but<100 pg/ml were included. Nine patients (15%) had MTC, with cytology being diagnostic in only four. Among the 51 patients without MTC, pro-Ctn was<0.1 ng/ml in 46 (90.2%). All patients with MTC had pro-Ctn>0.1 ng/ml. Basal Ctn was>24.6 pg/ml in all patients with MTC and in 42 patients (82.3%) without MTC. It is noteworthy that among patients with basal Ctn>24.6 pg/ml (n=18) pro-Ctn>0.1 ng/ml identified all patients with MTC and 64.2% of subjects with these pro-Ctn concentrations had this tumor. In conclusion, we did not find superiority of pro-Ctn over Ctn for the diagnosis of sporadic MTC in patients with nodular disease and mild or moderate hypercalcitoninemia. However, in the case of patients with hypercalcitoninemia in the gray zone, pro-Ctn has an excellent negative predictive value while the data regarding its positive predictive value are not uniform.

Calcitonin and complementary biomarkers in the diagnosis of hereditary medullary thyroid carcinoma in children and adolescents

OBJECTIVES

Medullary thyroid carcinoma (MTC) is a rare malignancy that is effectively curable by surgery. Unlike in adults, hereditary MTC has a predominant role in children. A fast and safe diagnosis is important to assure the good prognosis for the patients. A major cornerstone is the assessment of biomarkers, but the interpretation must respect their pre-, post- and analytical features. Especially calcitonin (Ctn) is a challenging biomarker in daily laboratory diagnostics. However, Ctn is of particular relevance for the diagnostic in MTC. The American Thyroid Association recommends thyroidectomy if the upper reference range of Ctn is exceeded. Interestingly, age-dependent reference ranges for children and adolescents have become available only recently for Ctn assays. With this review, we aim to highlight the importance of a timely diagnosis of MTC in children and adolescents.

CONTENT

Recent developments in pediatric biochemical diagnostics of MTC were summarized. This includes guidance on interpretation of RET, Ctn, procalcitonin, carcinoembryonic antigen, carbohydrate antigen 19-9, and chromogranin A.

SUMMARY

Currently, Ctn is the most investigated biomarker in the diagnosis of MTC in children and adolescents. Other biomarkers as PCT suggest complementary evidence about pediatric MTC but their interpretation based largely on adult's data. A successful treatment of MTC requires, besides results of biomarkers, information about medical history, RET gene analysis and recent guideline knowledge.

OUTLOOK

More research is required to validate complementary biomarkers of Ctn in children. Additionally, the effect of different confounder on pediatric Ctn levels has to be further clarified.

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.

The diagnostic accuracy of mid-regional pro-adrenomedullin for sepsis: a systematic review and meta-analysis

BACKGROUND

The incidence and mortality of sepsis are high, and common biomarkers are not perfect. To identify a biomarker with high specificity and sensitivity for sepsis, we evaluated the current literature on the performance of mid-regional pro-adrenomedullin (MR-proADM) in the diagnosis of sepsis.

METHODS

According to appropriate eligibility and exclusion criteria, PubMed, EMBASE, Cochrane Library, China Journal full-text Database, Wanfang Database and Chinese Journal Full Text Database were searched for "Mid-regional proadrenomedullin", "MR-proADM", "Sepsis", "Pyemia", "Pyohemia", "Septicemia" and "Blood poisoning". The publication dates considered for the search were from inception until August 31, 2020. The risk of bias was assessed according to QUADAS-2 criteria.

RESULTS

Eleven studies involving 2038 cases were included. MR-proADM had high sensitivity and specificity in the diagnosis of sepsis, with values of 0.83 [95% CI: (0.79-0.87)] and 0.90 [95% CI: (0.83-0.94)], respectively. The odds ratio of a combined diagnosis was 41.35, and the area under the curve (AUC) was 0.91. The best cut-off value for MR-proADM diagnosis of sepsis is 1-1.5 nmol/L. MRproADM may also have value in distinguishing pathogens and identifying sepsis severity and organ failure.

CONCLUSIONS

MR-proADM is an excellent biomarker for the diagnosis of sepsis with high sensitivity and specificity. The best cut-off value for MR-proADM diagnosis of sepsis is 1-1.5 nmol/L.

C-reactive protein and procalcitonin levels in prostate cancer

AIM

Prostate cancer (PCa) is one of the most common cancers among men in the world. Prostate-specific antigen is the most used biomarker for PCa diagnosis. In this study, we aimed to measure the procalcitonin (PCT) and C-reactive protein (CRP) levels in patients with PCa.

METHODS

The patients who underwent transrectal prostate biopsy and transurethral prostate surgery in the last 4 years were included in the study. The patients were divided into two groups according to the pathology reports, group1; benign prostate hyperplasia and group2; prostate cancer. MedCalc Statistical Software version 17.6 was used for statistical analyses.

RESULTS

The current study includes 149 patients. There were 118 patients in group 1 and 31 patients in group 2. The mean age of the patients was 66.85 and 69.41 years in groups respectively. Serum CRP and PCT levels were 3.33 and 0.01 in group 4.07 and 0.04 in group 2. Serum PCT levels were significantly higher in patients with PCa.

CONCLUSION

We found that the elevated procalcitonin level was associated with prostate cancer. Further studies are needed to define the relationship between procalcitonin and prostate cancer.

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.

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 performance of calcitonin and procalcitonin Elecsys® immunoassays in patients with medullary thyroid carcinoma

Objectives

Medullary thyroid carcinoma (MTC) is caused by a malignant transformation in the parafollicular C-cells of the thyroid, where calcitonin (CT) is released. Nowadays, CT is the main tumor marker used in the diagnosis and follow-up of MTC patients. Nonetheless, procalcitonin (PCT) has recently been proposed as a useful complementary/alternative biomarker in MTC. Our aims were to investigate the diagnostic performance of CT and PCT and their combination in the differential diagnosis between active and inactive MTC and between MTC and non-MTC thyroid diseases, respectively.

Methods

Serum samples were collected from 16 patients with active (i.e. primary tumour before surgery or post-surgical recurrent disease) and 23 with inactive (i.e. complete remission) MTC, 125 patients with non-MTC benign thyroid disease and 62 patients with non-MTC thyroid cancers, respectively. Elecsys® CT and PCT measurements were simultaneously performed on the Cobas e601 platform (Roche Diagnostics, Rotkreutz, Switzerland).

Results

Both CT and PCT median values in active MTC (94 pmol/L and 1.17 ng/mL, respectively) were significantly higher compared with inactive MTC (0.28 and 0.06) and either benign (0.37 and 0.06) or malignant (0.28 and 0.06) non-MTC. Undetectable PCT was found in five non-MTC patients with false positive CT results.

Conclusions

Elecsys® PCT assay is a highly sensitive and specific alternative MTC marker. At the very least it appears useful in patients with positive CT results as negative PCT values securely exclude active MTC. The availability of both markers on the same automated platform facilitates reflex or reflective strategies to refine the laboratory diagnosis.

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.

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.

Serum procalcitonin levels in prostate cancer: A new biomarker?

Background:

To examine the role of serum procalcitonin as a biomarker for the detection of prostate cancer in patients with a serum prostate-specific antigen less than 20.0 ng/mL.

Methods:

The prospective study included patients with a prostate-specific antigen level of 2–20 ng/mL, who underwent prostate biopsy. Clinical and pathological data such as age, prostate volume, prostate-specific antigen, procalcitonin, and Gleason score were reviewed. All patients were divided into three groups with total prostate-specific antigen level between 2 and 4 ng/mL, 4.1 and 10 ng/mL, and 10.1 and 20 ng/mL.

Results:

Of 227 patients who underwent biopsy, prostate cancer was diagnosed in 74 (32.6%) patients and the remaining 153 patients had a benign condition. The difference in mean serum procalcitonin values was significantly higher in the prostate cancer compared with the benign group (0.06 ± 0.03 vs 0.04 ± 0.03 ng/mL; p = 0.0001). Using a threshold of 0.045 ng/mL, procalcitonin was 54.1% sensitive and 80.3% specific (area under curve = 0.683). Serum procalcitonin levels were not able to differentiate between prostate cancer patients with prostate-specific antigen level of 2–4, 4.1–10, and 10.1–20 ng/mL.

Conclusion:

Based on this prospective study, procalcitonin can be a novel supplementary biomarker to increase the accuracy of prostate cancer screening.

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.

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.

The impact of tracheotomy on levels of procalcitonin in patients without sepsis: a prospective study

OBJECTIVE

Procalcitonin is a reliable biomarker of infection and sepsis. We aimed to determine whether tracheotomy influences the procalcitonin concentrations in patients without sepsis and assess whether operative duration and procedure affect the peak procalcitonin level.

METHODS

A total of 38 non-septic patients who required a tracheotomy underwent either a percutaneous dilatational tracheotomy (n=19) or a surgical tracheotomy (n=19). Procalcitonin levels were measured at the beginning of the tracheotomy and at 2 h, 4 h, 8 h, 24 h, 48 h and 72 h after the procedure.

RESULTS

The baseline procalcitonin concentration before the tracheotomy was 0.24 ± 0.13 ng/mL. The postoperative levels increased rapidly, with a 4-fold elevation after 2 h, reaching a peak 4 h later with a 5-fold increase over baseline. Thereafter, the levels gradually returned to 2-fold greater than the baseline level within 72 h. The peak levels of procalcitonin showed a significant positive correlation with operative durations (r=0.710, p<0.001) and procedures (rho=0.670, p<0.001).

CONCLUSION

In patients without sepsis, tracheotomy induces a rapid release of serum procalcitonin, and the operative duration and procedure have significant impacts on the peak procalcitonin levels. Thus, the nonspecific increase in procalcitonin levels following tracheotomy needs to be considered when this measure is used to evaluate infection.

Clinical diagnosis of sepsis and the combined use of biomarkers and culture- and non-culture-based assays

Sepsis is among the most common causes of death in hospitalized patients, and early recognition followed by immediate initiation of therapy is an important concept to improve survival in these patients. According to the definition of sepsis, diagnosis of sepsis requires the recognition of the systemic inflammatory response syndrome (SIRS) caused by infection as well as recognition of possible infection-related organ dysfunctions for diagnosis of severe sepsis or septic shock. Both SIRS and organ dysfunctions may occur frequently in hospitalized patients for various reasons. However, the fast recognition of acute infection as a cause of SIRS and newly developed organ dysfunction may be a demanding task since culture-based results of microbiological samples will be available only days after onset of symptoms. Biomarkers and PCR-based pathogen detection may help the physician in differentiating SIRS from sepsis. Procalcitonin (PCT) is the best investigated biomarker for this purpose. Furthermore, the current data support the usage of PCT for guidance of antimicrobial therapy. C-reactive protein (CRP) may be used to monitor the course of infection but has only limited discriminative capabilities. Interleukin-6 is widely used for its fast response to the infectious stimulus, but conclusive data for the application of this biomarker are missing. None of the available biomarkers can by itself reliably differentiate SIRS from sepsis but can aid and shorten the decision process. PCR-based pathogen detection can theoretically shorten the recognition of the underlying pathogen to about 8 h. However, this technique is expensive and requires additional staff in the laboratory; controlled prospective studies are missing. Although current studies suggest that PCR-based pathogen detection may be useful to shorten time to adequate antimicrobial therapy and diagnose invasive Candida infections, no general recommendations about the application of PCR for the diagnosis of sepsis can be given.

Utility of serum procalcitonin for screening and risk stratification of medullary thyroid cancer

CONTEXT

The clinical utility of procalcitonin has not been demonstrated across the whole spectrum of medullary thyroid cancer (MTC).

OBJECTIVE

This serum biomarker validation study aimed at defining the diagnostic accuracy of procalcitonin for screening and risk stratification of MTC and delineating biochemical thresholds predictive of lymph node involvement in the neck and mediastinum.

DESIGN AND SETTING

This was a retrospective analysis at a tertiary referral center.

PATIENTS

Included in this study were 457 consecutive patients with previously untreated MTC, 112 of whom had procalcitonin and calcitonin serum levels determined before the initial operation.

INTERVENTION

The intervention was compartment-oriented surgery.

MAIN OUTCOME MEASURES

Main outcome measures included primary tumor diameter, extrathyroidal extension, lymph node metastases, distant metastases, and biochemical cure.

RESULTS

Receiver operating characteristics analyses revealed similar diagnostic accuracy for procalcitonin vs the current calcitonin standard, yielding comparable areas under the curve for primary tumors at thresholds of 10 (0.94 vs 0.93) and 40 (0.92 vs 0.84) mm; extrathyroidal extension (0.84 vs 0.83), lymph node metastasis (0.88 vs 0.86), and distant metastasis (0.93 vs 0.91). Lymph node metastases were present in the ipsilateral lateral neck with procalcitonin levels ≤1.0 ng/mL and the ipsilateral central neck with procalcitonin levels ≤0.25 ng/mL. Above a threshold of 1.0 ng/mL, lymph node metastases emerged in the contralateral central and lateral neck and above 5.0 ng/mL also in the upper mediastinum. When procalcitonin levels exceeded 1, 5, 10, and 50 ng/mL, biochemical cure rates declined to no more than 71%, 36%, 23%, and 10%, respectively.

CONCLUSION

Serum procalcitonin, having comparable diagnostic accuracy, has great potential to replace serum calcitonin as a new standard of care in the management of MTC because it does not need to be kept cool on ice or frozen and is easier to manage at the community level.

Rapid diagnosis of sepsis

Fast and appropriate therapy is the cornerstone in the therapy of sepsis. However, the discrimination of sepsis from non-infectious causes of inflammation may be difficult. Biomarkers have been suggested to aid physicians in this decision. There is currently no biochemical technique available which alone allows a rapid and reliable discrimination between sepsis and non-infectious inflammation. Procalcitonin (PCT) is currently the most investigated biomarker for this purpose. C-reactive protein and interleukin 6 perform inferior to PCT in most studies and their value in diagnosing sepsis is not defined. All biomarkers including PCT are also released after various non-infectious inflammatory impacts. This shortcoming needs to be taken into account when biomarkers are used to aid the physician in the diagnosis of sepsis. Polymerase chain reaction (PCR) based pathogen detection may improve time to adequate therapy but cannot rule out the presence of infection when negative.