Standard pre- and postoperative determination of chromogranin a in resectable non-functioning pancreatic neuroendocrine tumors--diagnostic accuracy: NF-pNET and low tumor burden

Established and novel circulating neuroendocrine tumor biomarkers for diagnostic, predictive and prognostic use

The management of neuroendocrine tumors (NETs) represents a clinical challenge due to heterogeneity of their clinical behaviour, molecular biology and response to treatment. Over the years, several circulating biomarkers have been developed for the early diagnosis and follow-up of NETs. The specific secretory products of tumors associated with a secretory syndrome (functioning tumors) may be used as diagnostic and/or prognostic biomarkers while the most common non-specific circulating biomarkers, that may be increased in both functioning and non-functioning tumors, are chromogranin A and the neuron specific enolase. However, the diagnostic accuracy as well as the prognostic and predictive value of these biomarkers are limited and novel techniques of multianalyte analysis of regulators of tumor biology have been developed. The NETest has been most extensively studied and proved to be useful in NET diagnosis, early detection of post-operative recurrence and prediction of response to treatment but further investigation establishing higher level of evidence is required for implementation in clinical practice.

An Overview of Circulating Biomarkers in Neuroendocrine Neoplasms: A Clinical Guide

Neuroendocrine neoplasms (NENs) are a heterogeneous group of diseases that are characterized by different behavior and clinical manifestations. The diagnosis and management of this group of tumors are challenging due to tumor complexity and lack of precise and widely validated biomarkers. Indeed, the current circulating mono-analyte biomarkers (such as chromogranin A) are ineffective in describing such complex tumors due to their poor sensitivity and specificity. In contrast, multi-analytical circulating biomarkers (including NETest) are emerging as more effective tools to determine the real-time profile of the disease, both in terms of accurate diagnosis and effective treatment. In this review, we will analyze the capabilities and limitations of different circulating biomarkers focusing on three relevant questions: (1) accurate and early diagnosis; (2) monitoring of disease progression and response to therapy; and (3) detection of early relapse.

Role of chromogranin A-derived fragments after resection of nonfunctioning pancreatic neuroendocrine tumors

PURPOSE

No single reliable biomarker is available for nonfunctioning pancreatic neuroendocrine tumors (NF-PanNETs). Vasostatin-1 (VS-1), the N-terminal fragment of chromogranin A (CgA), seems to be a more accurate biomarker compared to its precursor. Primary aim was to investigate the ability of VS-1, compared to total-CgA, to assess the effectiveness of surgical resection performed for NF-PanNETs. Secondary aim was to evaluate two additional CgA-derived fragments, pancreastatin (PST) and vasostatin-2 (VS-2), as possible biomarkers for NF-PanNETs.

METHODS

Consecutive patients who underwent surgery for NF-PanNETs at San Raffaele Scientific Institute were included (n = 35). Plasma levels of CgA and CgA-derived fragments were measured by Enzyme-Linked ImmunoSorbent Assay (ELISA), preoperatively and postoperatively.

RESULTS

Preoperative VS-1 was significantly higher compared to VS-1 measured on postoperative day 5 (POD5) (pre: 0.338 nM versus POD5: 0.147 nM, P < 0.001), whereas total-CgA significantly increased after surgery (pre: 1.123 nM versus POD5: 1.949 nM, P = 0.006). Overall, 24 patients showed ≥ 1 feature of tumor aggressiveness (T3-T4, nodal/distant metastases, Ki67 > 5%, microvascular/perineural invasion, necrosis). The median percentage decrease in VS-1 plasma levels was 63% (IQR 28-88%) among patients with aggressive tumors, compared to 13% (IQR 0-57%) in the remaining population (P = 0.033). No significant differences in terms of PST (P = 0.870) and VS-2 (P = 0.909) were observed between preoperative and postoperative time.

CONCLUSION

VS-1 provides an early assessment of surgical efficacy in patients who undergo resection for NF-PanNETs, especially in those with aggressive neoplasms. Total-CgA, PST and VS-2 have no clinical utility in this setting.

Prognostic Value of Volume-Based Parameters Measured by SSTR PET/CT in Neuroendocrine Tumors: A Systematic Review and Meta-Analysis

Purpose: A meta-analysis was conducted to investigate the value of the volume parameters based on somatostatin receptor (SSTR)-positron emission tomography (PET) in predicting the prognosis in patients with neuroendocrine tumors (NETs). Material: PUBMED, EMBASE, Cochrane library, and Web of Knowledge were searched from January 1990 to May 2021 for studies evaluating prognostic value of volume-based parameters of SSTR PET/CT in NETs. The terms used were "volume," "positron emission tomography," "neuroendocrine tumors," and "somatostatin receptor." Pooled hazard ratio (HR) values were calculated to assess the correlations between volumetric parameters, including total tumor volume (TTV) and total-lesion SSTR expression (TL-SSTR), with progression-free survival (PFS) and overall survival (OS). Heterogeneity and subgroup analysis were performed. Funnel plots, Begg's and Egger's test were used to assess possible underlying publication bias. Results: Eight eligible studies involving 593 patients were included in the meta-analysis. In TTV, the pooled HRs of its prognostic value of PFS and OS were 2.24 (95% CI: 1.73-2.89; P < 0.00001) and 3.54 (95% CI, 1.77-7.09; P = 0.0004), respectively. In TL-SSTR, the pooled HR of the predictive value was 1.61 (95% CI, 0.48-5.44, P = 0.44) for PFS. Conclusion: High TTV was associated with a worse prognosis for PFS and OS in with patients NETs. The TTV of SSTR PET is a potential objective prognosis predictor.

Pretreatment Levels of Chromogranin A and Neuron-specific Enolase in Patients With Gastroenteropancreatic Neuroendocrine Neoplasia

BACKGROUND/AIM

Chromogranin A (CgA) and neuron-specific enolase (NSE) are applied in the diagnosis of neuroendocrine neoplasms (NENs), especially non-functional ones. The aim of this study was to investigate the predictive values of CgA and NSE in long-term survival.

PATIENTS AND METHODS

Our retrospective analysis included 65 patients with histologically verified gastroenteropancreatic NEN between 2005 and 2019. We performed bivariate and multivariable analyses to evaluate the relationship between CgA and NSE values before histological assessment and overall survival. Distribution of time-to-event was analyzed using Kaplan-Meier survival curves and modelled by Cox regression models.

RESULTS

Elevated NSE levels prior to histology were significantly associated with worse survival (HR=1.13, p=0.004) and were associated with low-differentiated NENs (r_s=0.321, p=0.0338). CgA was associated with well-differentiated tumors (r_s=0.233), but not significantly.

CONCLUSION

Pretreatment serum levels of NSE can serve as a valuable additional predictor of long-term survival in patients with NEN.

Limited Diagnostic Utility of Chromogranin A Measurements in Workup of Neuroendocrine Tumors

BACKGROUND

Plasma chromogranin A (CgA) is related to tumor burden and recommended in the follow-up of patients diagnosed with neuroendocrine tumors (NETs). The use of CgA in the workup of a suspected NET is more questionable.

OBJECTIVE

To assess the positive predictive value (PPV) of CgA plasma concentrations above the upper reference limit (URL) in patients with suspected NET.

METHOD

Patients referred to the NET Centre, Rigshospitalet, Copenhagen from 2015 to 2019 with clinically suspected NET were included if a CgA measurement was performed prior to referral. The utility of CgA was assessed by comparing pre-referral CgA concentrations to the outcome of a thorough workup. In 47 selected cases with continuously unexplained elevated CgA concentrations, a processing-independent analysis (PIA) for CgA was performed.

RESULTS

A total of 197 patients were included. NET was ultimately diagnosed in 25 patients. CgA plasma concentrations were above the URL (elevated) in 19/25 patients diagnosed with NET. In total, 167/197 had elevated CgA concentrations at referral. The positive predictive value (PPV) of elevated CgA concentration was 11% (19/167). Proton pump inhibitor (PPI) treatment was identified as the possible cause of CgA elevation in 55/148 patients with falsely elevated CgA. CgA concentration was normal in 28/47 patients when using PIA.

CONCLUSION

Our data do not support using measurement of CgA for screening when NET is suspected since the PPV was rather low. PPI treatment is a common cause of increased CgA concentrations and should always be discontinued before CgA measurement. PIA of CgA could be a way of excluding NET when suspicion is based primarily on elevated CgA.

Clinical and Molecular Risk Factors for Recurrence Following Radical Surgery of Well-Differentiated Pancreatic Neuroendocrine Tumors

Well-differentiated pancreatic neuroendocrine tumors are increasingly diagnosed neoplasms. For localized disease, surgery is the first-line therapy and is curative in most cases. However, although recurrence is a rare event, it can still occur up to 10 years from surgery, worsening the prognosis. Many clinical and pathological factors have been associated with recurrence; however, it is currently unclear how to accurately discern patients at risk for relapse of disease from those that should be considered cured. In this review, we focus on clinical, pathological, and molecular factors associated with recurrence and discuss available prediction tools to assess the risk of recurrence following surgery.

Circulating Neuroendocrine Gene Transcripts (NETest): A Postoperative Strategy for Early Identification of the Efficacy of Radical Surgery for Pancreatic Neuroendocrine Tumors

BACKGROUND

Surgery remains the only treatment for the cure of pancreatic neuroendocrine tumors (PanNETs). Biomarkers to identify the completeness of resection and predict recurrence are lacking.

OBJECTIVE

The aims of this study were to evaluate if the blood measurement of neuroendocrine gene transcripts (NETest) was diagnostic of PanNETs, and whether NETest blood levels could identify complete resection. We compared transcript analysis with the biomarker chromogranin A (CgA).

METHODS

This was a prospective, longitudinal, single-center study including 30 patients with a postoperative histological confirmation of PanNET. Blood for NETest and CgA was collected preoperatively and on postoperative day (POD) 1, POD5, and POD30. Transcripts were measured by real-time quantitative reverse transcription polymerase chain reaction and multianalyte algorithmic analysis (NETest; normal < 20), and CgA was measured by enzyme-linked immunosorbent assay (ELISA; normal < 109 ng/mL). Data are expressed as mean ± standard deviation (SD).

RESULTS

Pancreatic surgical resections (n = 30) were R0, 26; R1, 2; and R2, 2. Preoperatively, NETest score was elevated in all 30 patients (44.7 ± 27), but postoperatively, NETest scores significantly decreased (p = 0.006) to POD30 (24.7 ± 24). The proportion of patients (15/30) with an elevated score significantly decreased by POD30 (p < 0.0001). CgA levels were elevated preoperatively (184 ± 360 ng/mL) in only 9/30 patients, but did not decrease significantly postoperatively at POD30 (260 ± 589 ng/mL, p = 0.398). The number of patients with elevated CgA levels remained unchanged (9/30).

CONCLUSIONS

The NETest is an accurate diagnostic biomarker for PanNETs (100%). A decrease in NETest levels after radical resection suggests this blood test provides early assessment of surgical efficacy. CgA had no clinical utility.

The impact of surgery for metastatic pancreatic neuroendocrine tumor: a contemporary evaluation matching for chromogranin a level

BACKGROUND

Studies supporting surgical management of metastatic pancreatic neuroendocrine tumor (PNET) are limited by selection bias. Chromogranin A (CgA) has been used as a biomarker for PNET and may reflect disease burden or biology. This study aimed to correlate CgA level with overall survival and to use it to match patients selected for different treatment approaches in an analysis of the impact of surgical management.

METHODS

1478 patients diagnosed with PNET in the National Cancer Database (2004-2014) were retrospectively identified, and logistic regression analyses were used to evaluate associations between the presence of metastatic disease and CgA level. After matching patients by CgA level and other factors predictive of surgical management, Kaplan-Meier survival analysis was performed.

RESULTS

Median CgA level was significantly higher in metastatic versus localized PNET(169 ng/mL versus 66 ng/mL, p < 0.001). On multivariate logistic regression, CgA level was predictive of metastatic disease(OR 1.002, p < 0.001) and survival in metastatic and non-metastatic patients. After matching for CgA level, surgery was associated with improved overall survival.

DISCUSSION

CgA level is predictive of the presence of distant metastatic disease and overall survival in PNET. When matched by CgA and other predictors of treatment approach, patients with metastatic PNET undergoing surgery have improved survival.

Neuroendocrine Neoplasms of the Small Bowel and Pancreas

The traditionally promulgated perspectives of neuroendocrine neoplasms (NEN) as rare, indolent tumours are blunt and have been outdated for the last 2 decades. Clear increments in their incidence over the past decades render them increasingly clinically relevant, and at initial diagnosis many present with nodal and/or distant metastases (notably hepatic). The molecular pathogenesis of these tumours is increasingly yet incompletely understood. Those arising from the small bowel (SB) or pancreas typically occur sporadically; the latter may occur within the context of hereditary tumour predisposition syndromes. NENs can also be associated with endocrinopathy of hormonal hypersecretion. Tangible advances in the development of novel biomarkers, functional imaging modalities and therapy are especially applicable to this sub-set of tumours. The management of SB and pancreatic neuroendocrine tumours (NET) may be challenging, and often comprises a multidisciplinary approach wherein surgical, medical, interventional radiological and radiotherapeutic modalities are implemented. This review provides a comprehensive overview of the epidemiology, pathophysiology, diagnosis and treatment of SB and pancreatic NETs. Moreover, we provide an outlook of the future in these tumour types which will include the development of precision oncology frameworks for individualised therapy, multi-analyte predictive biomarkers, artificial intelligence-derived clinical decision support tools and elucidation of the role of the microbiome in NEN development and clinical behaviour.

Prognostic and predictive factors on overall survival and surgical outcomes in pancreatic neuroendocrine tumors: recent advances and controversies

Introduction: Recent advances in diagnostic modalities and therapeutic agents have raised the importance of prognostic factors in predicting overall survival, as well as predictive factors for surgical outcomes, in tailoring therapeutic strategies of patients with pancreatic neuroendocrine neoplasms (panNENs).Areas covered: Numerous recent studies of panNEN patients report the prognostic values of a number of clinically related factors (clinical, laboratory, imaging, treatment-related factors), pathological factors (histological, classification, grading) and molecular factors on long-term survival. In addition, an increasing number of studies showed the usefulness of various factors, specifically biomarkers and molecular makers, in predicting recurrence and mortality related to surgical treatment. Recent findings (from the last 3 years) in each of these areas, as well as recent controversies, are reviewed.Expert commentary: The clinical importance of prognostic and predictive factors for panNENs is markedly increased for both overall outcome and post resection, as a result of recent advances in all aspects of the diagnosis, management and treatment of panNENs. Despite the proven prognostic utility of routinely used tumor grading/classification and staging systems, further studies are required to establish these novel prognostic factors to support their routine clinical use.

Limited role of Chromogranin A as clinical biomarker for pancreatic neuroendocrine tumors

BACKGROUND

Serum Chromogranin A (CgA) is widely used as a biomarker for pancreatic neuroendocrine tumors (PanNETs). The aim of this study was to investigate the value of CgA as a diagnostic and prognostic marker for well-differentiated PanNETs.

METHODS

Patients with well-differentiated PanNET and a baseline CgA measurement, between 2011 and 2016 were reviewed. The diagnostic value was determined by comparing CgA values from patients with PanNETs to those with other pancreatic neoplasms and healthy controls. The Kaplan-Meier method was used to investigate the CgA prognostic significance.

RESULTS

Ninety-nine patients met inclusion criteria. As a diagnostic marker, CgA had a sensitivity of 66%, specificity of 95%, and overall accuracy of 71%. The use of PPIs was associated with a higher CgA level (p = 0.015). When excluding patients on PPIs, CgA accuracy in distinguishing PanNETs from other pancreatic neoplasms was 66%, the sensitivity and specificity were 60% and 75% respectively. Elevated CgA (p = 0.004), Ki67% (p < 0.001), tumor grade (p < 0.001) and stage of disease (p = 0.036) were associated with disease-specific survival.

CONCLUSION

CgA has a limited role as a diagnostic biomarker for well-differentiated PanNETs. An elevated CgA level may have prognostic value but its role should be further investigated with respect to other known pathological factors.

Association between preoperative Vasostatin-1 and pathological features of aggressiveness in localized nonfunctioning pancreatic neuroendocrine tumors (NF-PanNET)

BACKGROUND

A reliable and accessible biomarker for nonfunctioning pancreatic neuroendocrine tumors (NF-PanNET) is currently unavailable. Chromogranin A (CgA) represents the best-described neuroendocrine biomarker, but its accuracy is low. Vasostatin-1 (VS-1), a fragment derived from the cleavage of CgA, was recently investigated and found to be more accurate as tumor biomarker in a cohort of patients affected by mainly metastatic small intestinal NET.

METHODS

Patients submitted to surgery for sporadic localized NF-PanNET at San Raffaele Hospital were included. Preoperative plasma samples were prospectively collected. Circulating levels of total-CgA and VS-1 were retrospectively investigated by sandwich Enzyme-Linked ImmunoSorbent Assays.

RESULTS

Overall, 50 patients were included. VS-1 value (P=0.0001) was the only preoperatively retrievable factor independently associated with NF-PanNET size. No significant correlation between CgA and tumor diameter was found (P = 0.057). A VS-1 value of 0.39 nM was identified as the optimal VS-1 cut-off accurately associated with NF-PanNET larger than 4 cm. Patients with VS-1 > 0.39 nM had a significantly higher frequency of microvascular invasion (P = 0.005) and nodal metastasis (P = 0.027). Median VS-1 plasma level was significantly higher in the presence of microvascular invasion (P = 0.001) and nodal metastasis (P = 0.012). PPI assumption significantly increased total-CgA levels, but not those of VS-1 (P = 0.111).

CONCLUSIONS

In localized, non-metastatic NF-PanNET, VS-1 is strongly associated to tumor dimension and its plasma levels are significantly higher in the presence of microvascular invasion and nodal metastases; moreover, VS-1 value is not affected by the PPI use.

Chromogranin A in the Follow-up of Gastroenteropancreatic Neuroendocrine Neoplasms: Is It Really Game Over? A Systematic Review and Meta-analysis

OBJECTIVES

Little is known about chromogranin A (CgA) during follow-up of gastroenteropancreatic neuroendocrine neoplasms. We hypothesized that serial CgA monitoring might be useful for the assessment of tumor progression, and we performed a systematic review of the literature and meta-analysis.

METHODS

A bibliographical search was performed in PubMed using "chromogranin A" and "neuroendocrine tumors" and "follow-up" and "biomarker" to identify all pertinent articles published in the last 10 years.

RESULTS

Eight studies were included in current meta-analysis. Chromogranin A as a follow-up marker shows sensitivity between 46% and 100% and specificity between 68% and 90%. The meta-analysis results showed an overall accuracy of 84% (95% confidence interval [CI], 81-86.6), a cumulative sensitivity of 74.6% (95% CI, 61.9-85.4), and a cumulative specificity of 84.7% (95% CI, 81.3-87.7). These data indicate that circulating CgA has a better overall accuracy in the follow-up setting; it can be used to rule the diagnosis of recurrence/progression in, rather than to rule it out.

CONCLUSIONS

Chromogranin A is more reliable when used to monitor disease progression and response to treatment and for the early detection of recurrence after treatment rather than in the diagnostic setting. It is more sensible to use this marker in those cases where the initial values were impaired.

Measurement of circulating transcript levels (NETest) to detect disease recurrence and improve follow-up after curative surgical resection of well-differentiated pancreatic neuroendocrine tumors

BACKGROUND

Recurrence of pancreatic neuroendocrine tumors (pNET) after surgery is common. Strategies to detect recurrence have limitations. We investigated the role of clinical criteria and the multigene polymerase chain reaction-based NETest during post-operative follow-up of pNET.

METHODS

We studied 3 groups of resections: R0 with no recurrence (n = 11), R0 with recurrence (n = 12), and R1 with no recurrence (n = 12). NETest levels (>40%) were compared with chromogranin A (CgA) and clinicopathological criteria (CC; grade, lymph node metastases, size). Nonparametric, receiver operating characteristics, logistic regression, and predictive feature importance analyses were performed.

RESULTS

NETest was higher in R0 with recurrence (56 ± 8%) compared with R1 with no recurrence (39 ± 6%) and R0 with no recurrence (28 ± 6%, P < .005). NETest positively correlated with recurrence (area under the curve: 0.82), CgA was not (area under the curve: 0.51 ± 0.09). Multiple regression analysis defined factor impact as highest for NETest (P < .005) versus CC (P < .03) and CgA (P = .23). NETest gave false positive or negative recurrence in 18% using a 40% cutoff. Logistic regression modeling of CC was 83% accurate; it was 91% when the NETest was included. Combining CC and NETest was approximately 2× more effective than individual CC alone (increase in R ² value from 43% to 80%).

CONCLUSIONS

A multigene blood test facilitates effective identification of pNET recurrence, prediction of disease relapse, and outperforms CgA.

Low accuracy of chromogranin A for diagnosing early-stage pancreatic neuroendocrine tumors

The aim of the present study was to evaluate the clinical utility of plasma chromogranin A (CgA) in patients diagnosed with early-stage pancreatic neuroendocrine tumors (PNETs) in terms of diagnostic value and treatment response. A total of 35 patients with PNETs were prospectively enrolled from August 2010 to April 2014. Demographic and clinicopathological data were collected, and serial plasma CgA levels were measured. Tumor responses were defined by the Response Evaluation Criteria In Solid Tumors criteria. Pearson's χ2 test was used for the analysis of the association between the plasma CgA level and various factors. Plasma CgA level was significantly associated with the size (P=0.03), metastasis (P=0.02) and tumor stage (P=0.03) of the PNETs. Using 126 U/l as the optimal cutoff value, the sensitivity and specificity were 87.5 and 81.5%, respectively. For localized tumors, the sensitivity of CgA for diagnosing PNETs was relatively low, even following a lowering of the cutoff values (29.6–51.9%). Plasma CgA level was correlated with therapeutic response in those patients with high baseline CgA levels (P=0.025), but not in the patients with low baseline CgA levels (P=0.587). In conclusion, plasma CgA level was associated with tumor size, metastasis and tumor stage in patients with PNET. For early-stage PNETs, CgA exhibited a limited role in diagnosis and treatment response evaluation in the population of the present study.

Chromogranin A as circulating marker for diagnosis and management of neuroendocrine neoplasms: more flaws than fame

Owing to the heterogeneity of neuroendocrine neoplasms (NENs), the availability of reliable circulating markers is critical for improving diagnostics, prognostic stratification, follow-up and definition of treatment strategy. This review is focused on chromogranin A (CgA), a hydrophilic glycoprotein present in large dense core vesicles of neuroendocrine cells. Despite being long identified as the most useful NEN-related circulating marker, clinical application of CgA is controversial. CgA assays still lack standardization, thus hampering not only clinical management but also the comparison between different analyses. In the diagnostic setting, clinical utility of CgA is limited as hampered by (a) the variety of oncological and non-oncological conditions affecting marker levels, which impairs specificity; (b) the fact that 30-50% of NENs show normal CgA, which impairs sensitivity. Regarding the prognostic phase, there is prospective evidence which demonstrates that advanced NENs secreting CgA have poorer outcome, as compared with those showing non-elevated marker levels. Although the identification of cut-offs allowing a proper risk stratification of CgA-secreting patients has not been performed, this represents the most important clinical application of the marker. By contrast, based on prospective studies, the trend of elevated circulating CgA does not represent a valid indicator of morphological evolution and has therefore no utility for the follow-up phase. Ultimately, current knowledge about the role of the marker for the definition of treatment strategy is poor and is limited by the small number of available studies, their prevalent retrospective nature and the absence of control groups of untreated subjects.

Chromogranin A: any relevance in neuroendocrine tumors?

PURPOSE OF REVIEW

The review summarizes the utility and limitations of chromogranin A (CgA) as a circulating biomarker for neuroendocrine tumors (NETs).

RECENT FINDINGS

Blood CgA measurement has numerous clinical limitations including poor assay reproducibility, low sensitivity (meta-analysis: 73%, 95% confidence interval: 0.71-0.76), and a paucity of prospective validation studies. A recent study noted elevation in 27% of NETs with a predictive value of 50% for metastases. These findings are consistent with its efficacy primarily as a monoanalyte secretory rather than multidimensional neoplastic marker. An automated CgA assay (KRYPTOR) exhibits similar metrics to the DAKO assay but is only useful in serum and routine storage diminishes its accuracy. Current studies indicate that CgA is more effective as a biomarker for cardiac disease. Given the diverse limitations of CgA, NET biomarker focus has evolved toward measurement of multiple analytes, for example, transcripts. Multianalyte algorithmic analyses perform significantly better as diagnostic (>95%) and prognostic markers (>90%) than CgA (30-74 and ∼50%, respectively) since they delineate different aspects of the biological behavior of NETs, (e.g., proliferome and metabolome).

SUMMARY

CgA is neither a reliable nor robust NET biomarker. As a monoanalyte, it is restricted by poor metrics and has limited predictive value. Its current clinical utility appears optimal in cardiovascular disease. The significance of CgA in NET disease is diminishing as other analytical approaches, particularly transcript multianalyte assays or other strategies, evolve to supersede it.