Chromogranin A as a determinant of midgut carcinoid tumour volume

[Clinical significance of neuroendocrine tumors : Incidence, symptoms, diagnosis, stage, and prognostic factors and their influence on disease management]

BACKGROUND

Neuroendocrine neoplasms (NEN) are heterogenous with an increasing incidence in recent years.

OBJECTIVES

Overview on incidence, symptoms, diagnostics, grading, imaging and prognostic determinants, including factors having an impact on therapeutic management.

METHODS

Review on current literature, including original articles, reviews, guidelines and expert opinions.

RESULTS

NEN are mainly located in the gastrointestinal tract and their incidence has increased in recent years, mainly due to improved diagnostics, e.g., cross-sectional imaging. Clinical characteristics include hormone excess syndromes (carcinoid syndrome). Laboratory markers such as chromogranin A are commonly used as part of routine diagnostics, followed by endoscopic and endosonographic procedures, which also allow biopsies to be obtained. Tumor spread can be determined by contrast-enhanced computed tomography/magnetic resonance imaging (CT/MRI) or somatostatin receptor (SSRT)-PET/CT (positron emission tomography). Prognostic factors include Ki67 index, type, and grading. Resection with curative intent is the therapy of choice. In a metastasized setting, SSRT-directed treatment approaches are favored, while in dedifferentiated NEN, conventional chemotherapy is needed.

CONCLUSION

A broad diagnostic armamentarium can be offered to NEN patients and the improved diagnostic procedures have most likely caused a raising incidence in recent years. Among others, prognostic factors are Ki67 and NEN subtypes; these clinical determinants also have an impact on patient management.

A Perforated Colonic Neuroendocrine Tumor with Liver Metastasis: A Case Report and Literature Review

BACKGROUND Neuroendocrine neoplasms (NENs) originate from cells of the endocrine and nervous systems, and they are rarely encountered in colorectal cases with no specific symptoms. The incidence and prevalence of NENs of the large bowel are increasing. Malignant colonic types are known to have poor diagnosis. The mean age of colonic NENs is the seventh decade, and the risk of NENs is increased 4-fold with affected first-degree family members. CASE REPORT A 57-year-old male patient presented to our Emergency Department with a 5-day history of severe generalized abdominal pain associated with worsening abdominal distension, history of night sweats, and weight loss. A CT scan of the abdomen and pelvis demonstrated a large heterogeneously enhancing neoplastic mass lesion involving the splenic flexure of the colon surrounded by fat stranding with a small contained leak, in addition to multiple metastatic hypodense focal hepatic lesions. Multiple lymph nodes under 1 cm in size were also noted. The patient underwent exploratory laparotomy, subtotal colectomy, ileostomy creation, and washout. The histopathological exam revealed high-grade invasive colonic neuroendocrine carcinoma, which was pT4N2bM1c, while the peritoneal lesion was metastatic carcinoma. The patient was then referred to the multidisciplinary tumor board. CONCLUSIONS Unusual presentation of neuroendocrine tumors is shown to be expected. Since colorectal NECs are rare, highly aggressive diseases and usually discovered very late, individualization of management, as well as additional research, is required.

Intestinal occlusion by stenotic neuroendocrine tumours of left colon and concomitant association with small bowel gastrointestinal stromal tumours: A case report

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Gastrointestinal stromal tumours (GIST) and Neuroendocrine tumours (NET) of the gastroenteropancreatic tract are rare neoplasms.

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Treatment for colonic NETs was similar to colonic adenocarcinoma, with segmental resection and lymphadenectomy.

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The associationof GIST and NET is difficult to suspect Serum CgA remains the most important biochemical marker in the diagnostics, monitoring, and establishing the prognosis in colorectal NETs.

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Early diagnosis of concomitant tumors such as GIST and NET will guarantee a better outcome of patients.

Introduction

The association between Gastrointestinal Stromal Tumours (GIST) and Neuroendocrine Tumours (NET) is very rare. These tumours have various clinical expressions and sometimes are asymptomatic. Synchronous NETs and GISTs have been already described in literature in few case reports. On the other hand, there is no mention of concomitant presence of discending colon NEC-G3 and small intestinal GIST.

Presentation of case: we presented a case of a patient with clinical evidence of intestinal occlusion and radiological and intraoperative aspects of an adenocarcinoma of the left colon with a single metastasis on small bowel. The pathology analysis of the tumour showed a stenotic left colon NEC-G3 and a small bowel GIST.

Discussion

In this case report GIST was surgically treated as a small bowel ripetitive lesion and NET as a left colon adenocarcinoma. These tumours may have a similar presentation in terms of symptoms, endoscopic findings and imaging results.

Conclusion

Concomitant NEC and GIST is rare but it is important to investigate patients before surgery in order to distinguish these from other tumours because of the different prognosis.

Mesenteric fibrosis and palliative surgery in small intestinal neuroendocrine tumours

Mesenteric fibrosis (MF) surrounding a mesenteric mass is a hallmark feature of small intestinal neuroendocrine tumours (SI-NETs). Since this can induce intestinal obstruction, oedema and ischaemia, prophylactic resection of the primary tumour and mesenteric mass is often recommended. This study assessed the predictors for mesenteric metastasis and fibrosis and the effect of MF and palliative surgery on survival. A retrospective analysis of 559 patients with pathologically proven SI-NET and available CT-imaging data was performed. Clinical characteristics, presence of mesenteric mass and fibrosis on CT imaging and the effect of palliative abdominal surgery on overall survival were assessed. We found that MF was present in 41.4%. Older age, 5-HIAA excretion ≥67 μmol/24 h, serum CgA ≥121.5 μg/L and a mesenteric mass ≥27.5 mm were independent predictors of MF. In patients ≤52 years, mesenteric mass was less often found in women than in men (39% vs 64%, P = 0.002). Corrected for age, tumour grade, CgA and liver metastasis, MF was not a prognostic factor for overall survival. In patients undergoing palliative surgery, metastasectomy of mesenteric mass or prophylactic surgery did not result in survival benefit. In conclusion, we confirmed known predictors of MF and mesenteric mass and suggest a role for sex hormones as women ≤52 years have less often a mesenteric mass. Furthermore, the presence of MF has no effect on survival in a multivariate analysis, and we found no benefit of metastasectomy of mesenteric mass or prophylactic surgery on overall survival.

Clinical Presentation and Diagnosis of Neuroendocrine Tumors

Neuroendocrine tumors (NETs) are slow-growing neoplasms capable of storing and secreting different peptides and neuroamines. Some of these substances cause specific symptom complexes, whereas others are silent. They usually have episodic expression, and the diagnosis is often made at a late stage. Although considered rare, the incidence of NETs is increasing. For these reasons, a high index of suspicion is needed. In this article, the different clinical syndromes and the pathophysiology of each tumor as well as the new and emerging biochemical markers and imaging techniques that should be used to facilitate an early diagnosis, follow-up, and prognosis are reviewed.

Non-L-cell immunophenotype and large tumor size in rectal neuroendocrine tumors are associated with aggressive clinical behavior and worse prognosis

According to the 2010 World Health Organization classification, all gastrointestinal neuroendocrine tumors (NETs) are classified as malignant except for L-cell-type (glucagon-like peptide [GLP] and peptide YY [PYY]-producing) NETs. However, L-cell immunophenotype in rectal NETs has not been widely studied previously. Immunohistochemical labeling of L-cell markers with GLP1 and PYY was performed in 208 surgically or endoscopically resected rectal NET cases with tissue microarrays and was compared with clinicopathologic features and patient survival. Rectal NETs with non-L-cell immunophenotype and large tumor size (>1 cm) were associated with increased tumor grading, advanced T category, lymphovascular and perineural invasions, and lymph node and distant metastases (P<0.001, each). Rectal NET patients with non-L-cell phenotype and measuring >1 cm had significantly worse survival outcome than other groups by univariate (P<0.001) and multivariate (P<0.001) analyses. In summary, non-L-cell immunophenotype and large tumor size are associated with increased tumor grading and staging, concurrently indicating that they are independently poor prognostic indicators in rectal NET patients. Therefore, combining L-cell phenotype and tumor size can demonstrate the clinical behavior of rectal NETs more precisely than use of L-cell immunophenotype alone.

Pancreastatin predicts survival in neuroendocrine tumors

BACKGROUND

Serum neurokinin A, chromogranin A, serotonin, and pancreastatin reflect tumor burden in neuroendocrine tumors. We sought to determine whether their levels correlate with survival in surgically managed small bowel (SBNETs) and pancreatic neuroendocrine tumors (PNETs).

METHODS

Clinical data were collected with Institutional Review Board approval for patients undergoing surgery at one center. Progression-free (PFS) and overall (OS) survival were from the time of surgery. Event times were estimated by the Kaplan-Meier method. Preoperative and postoperative laboratory values were tested for correlation with outcomes. A multivariate Cox model adjusted for confounders.

RESULTS

Included were 98 SBNETs and 78 PNETs. Median follow-up was 3.8 years; 62 % had metastatic disease. SBNETs had lower median PFS than PNETs (2.0 vs. 5.6 years; p < 0.01). Median OS was 10.5 years for PNETs and was not reached for SBNETs. Preoperative neurokinin A did not correlate with PFS or OS. Preoperative serotonin correlated with PFS but not OS. Higher levels of preoperative chromogranin A and pancreastatin showed significant correlation with worse PFS and OS (p < 0.05). After multivariate adjustment for confounders, preoperative and postoperative pancreastatin remained independently predictive of worse PFS and OS (p < 0.05). Whether pancreastatin normalized postoperatively further discriminated outcomes. Median PFS was 1.7 years in patients with elevated preoperative pancreastatin versus 6.5 years in patients with normal levels (p < 0.001).

CONCLUSIONS

Higher pancreastatin levels are significantly associated with worse PFS and OS in SBNETs and PNETs. This effect is independent of age, primary tumor site, and presence of nodal or metastatic disease. Pancreastatin provides valuable prognostic information and identifies surgical patients at high risk of recurrence who could benefit most from novel therapies.

Clinical presentation, recurrence, and survival in patients with neuroendocrine tumors: results from a prospective institutional database

The rarity of neuroendocrine tumors (NET) has contributed to a paucity of large epidemiologic studies of patients with this condition. We characterized presenting symptoms and clinical outcomes in a prospective database of over 900 patients with NET. We used data from patient questionnaires and the medical record to characterize presenting symptoms, disease-free survival (DFS), and overall survival (OS). The majority of patients in this database had gastroenteropancreatic NET. The median duration of patient-reported symptoms before diagnosis was 3.4 months; 19.5% reported durations from 1 to 5 years, 2.5% from 5 to 10 years, and 2% >10 years. The median DFS among patients with resected small bowel NET or pancreatic NET (panNET) was 5.8 and 4.1 years respectively. After correcting for left truncation bias, the median OS was 7.9 years for advanced small bowel NET and 3.9 years for advanced panNET. Chromogranin A (CGA) above twice the upper limit of normal was associated with shorter survival times (hazard ratios 2.8 (1.9, 4.0) P<0.001) in patients with metastatic disease, regardless of tumor subtype. Our data suggest that while most NET patients are diagnosed soon after symptom onset, prolonged symptom duration before diagnosis is a prominent feature of this disease. Though limited to observations from a large referral center, our observations confirm the prognostic value of CGA and suggest that median survival durations may be shorter than that reported in other institutional databases.

[Chromogranin A and neuroendocrine tumors]

Chromogranin A (CgA) is the most abundant granin in gastroenteropancreatic neuroendocrine tumors (GEP-NETs). As a tumor marker is moderately sensitive and nonspecific. Despite the limitations of testing methods, which require careful interpretation, especially in the case of gastrinomas, patients treated with somatostatin analogues, and poorly differentiated tumors, it is the best tumor marker in GEP-NETs and may be of value in other tumors with neuroendocrine differentiation. CgA may be used as a marker in blood or tissue samples through immunohistochemical techniques. CgA levels correlate with tumor burden and extension and may be used for diagnosis and monitoring of GEP-NETs, especially midgut carcinoids and endocrine pancreatic tumors. It is also useful as a prognostic marker for detection of recurrence and monitoring of response to different treatments.

Contemporary methods of therapy and follow-up of neuroendocrine tumours of the gastrointestinal tract and the pancreas

The growing interest in neuroendocrine tumours is due to the dynamic growth of detection of this type of cancer. Neuroendocrine tumours (neuroendocrine neoplasms - NENs / neuroendocrine tumours - NETs) derive from glands, groups of endocrine cells and diffuse neuroendocrine system cells. Mainly they derive from the gastrointestinal tract (gastroenteropancreatic-neuroendocrine tumours - GEP-NETs). Currently the modified WHO classification from 2010 is widely used. An important element in the choice of treatment is histological maturity based on mitotic activity and on assessment of proliferation activity (Ki-67). The treatment of choice is surgery. In most cases, complete surgical removal is impossible because of the advanced staging at the time of diagnosis. In well-differentiated neoplasms where the expression of somatostatin receptors is expected, patients are qualified for somatostatin analogues therapy. Poorly differentiated lesions are qualified for chemotherapy. In the guidelines of ENETS (European Neuroendocrine Tumor Society) from 2007 the rules concerning monitoring depending on the WHO classification were specified.

Multifocal colorectal adenocarcinoma with a synchronous multifocal carcinoid of the small intestine--case report and literature review

The paper presents a case report of coexisting multifocal colorectal cancer and multifocal carcinoid of the small intestine. Our literature review did not demonstrate any report of such case. We emphasize necessity of careful inspection of abdominal cavity during any surgical procedure since small lesions, in particular in the small intestine, may be omitted--as was the case during the initial colectomy in our case. Current epidemiological data are also presented and standards of management for diagnosis and treatment of gastrointestinal carcinoid.

Chromogranin a as serum marker for gastroenteropancreatic neuroendocrine tumors: a single center experience and literature review

The aim of this study was to assess the clinical sensitivities of the tumor markers chromogranin A (CgA), urinary 5-hydroxyindoleacetic acid (5-HIAA) and alkaline phosphatase (AP) in neuroendocrine tumors (NETs) of the GastroEnteroPancreatic-(GEP-) system depending on tumor primary location and metastatic spread. In a retrospective single-center series, sensitivities were evaluated in serum samples from 110 patients with midgut (n = 62) and pancreatic (n = 48) NETs. CgA levels were analyzed by a commercially-available immunoradiometric assay (CIS-bio) during routine follow-up in the years 2000–2009. CgA showed a higher sensitivity for midgut (68%) than pancreatic (54%) NETs. A higher CgA sensitivity and significantly higher median CgA values were found in patients with liver metastases than in those without, and in patients with hepatic and additionally extra-hepatic metastases than in those with hepatic and nodal metastases alone, respectively. We found an overall sensitivity for elevated 5HIAA excretion of 69% for midgut NETs and a significant correlation between median CgA and 5-HIAA values. The sensitivity of AP and the correlations of AP/CgA-data-pairs were low in both midgut and pancreatic NETs, although highest for metastatic pancreatic NETs. The sensitivity of CgA measurement depends on the NET primary location and spread of disease. 5-HIAA and CgA showed comparable sensitivity in midgut NETs, while AP does not seem to be useful as a tumor marker in GEP-NETs.

Prognostic clinicopathologic factors in longitudinally followed patients with metastatic small bowel carcinoid tumors

OBJECTIVES

Neuroendocrine tumors demonstrate heterogeneous behavior based on the site of origin and histology. This study aimed to delineate prognostic clinicopathologic features in patients with metastatic midgut carcinoid.

METHODS

All patients underwent resection of the primary tumor in the setting of metastatic disease. Survival was measured from the date of primary tumor resection and calculated by Kaplan-Meier estimation. Clinical data include age, sex, serum biomarkers, primary tumor size, Ki-67 index, and the performance of hepatic cytoreductive procedure. Serially collected serum biomarkers were considered as mean values within periods relative to primary resection: preoperative, 0 to 1 year postoperative, and years 1 to 5 postoperative. Log-rank comparisons were used to assess the prognostic value of the aforementioned features.

RESULTS

Forty-nine patients (21 men) with metastatic midgut carcinoid who underwent primary tumor resection were identified. Median survival was 121 months. The overall 5-year survival rate was 83%. Age higher than 65 years (P = 0.01) and late postoperative chromogranin A (CgA; P = 0.02) were associated with decreased survival.

CONCLUSIONS

This study highlights the favorable prognosis of patients with metastatic small bowel carcinoid in a multidisciplinary treatment program. Among other factors, elevated postoperative CgA is associated with decreased survival. The significance of increased CgA over time underlies the importance of longitudinal follow-up for these patients.

Choice of tumour markers in patients with neuroendocrine tumours is dependent on the histological grade. A marker study of Chromogranin A, Neuron specific enolase, Progastrin-releasing peptide and cytokeratin fragments

BACKGROUND

Chromogranin A (CgA) is the most important tumour marker for well-differentiated neuroendocrine tumours (NET) and neuron specific enolase (NSE) for poorly differentiated neuroendocrine carcinoma (NEC). This study investigated whether the markers progastrin-releasing peptide (proGRP) and cytokeratin fragments (CKfr) CK8, CK18 and CK19 (MonoTotal) can be of additional value to the histological classification and help predict survival in these patients.

METHODS

CgA, NSE, proGRP and CKfr were measured in 242 patients with grade 1 NET (G1NET), 38 with grade 2 NET (G2NET), 42 with large cell NEC (LCNEC), 251 with small cell NEC (SCNEC) and in 282 healthy persons. Results were compared with tumour characteristics and survival by means of Receiver Operating Characteristics (ROC) curves and Cox regression analyses.

RESULTS

The largest area under the ROC curve was for CgA (0.86, 0.91 and 0.90, respectively) when comparing patients with G1NET, G2NET and LCNEC with healthy persons. ProGRP showed the highest sensitivity (73%) at 95% specificity in patients with SCNEC. In a multivariate survival analysis, only CKfr was associated with survival (P<0.0001) for patients with well-differentiated NET (G1NET and G2NET). For patients with poorly differentiated NEC, both CKfr and NSE were associated with survival (P<0.0001 and P=0.003, respectively).

CONCLUSION

Within all histological groups a combination of tumour markers proved to be more informative as diagnostic and prognostic marker than each marker alone. In patients with well-differentiated NET and LCNEC we recommend the use of CgA and CKfr, whilst in patients with SCNEC, proGRP and CKfr are preferred.

Different gene expression profiles in metastasizing midgut carcinoid tumors

The genetic events leading the progression of midgut carcinoid tumors are largely unknown. The disease course varies from patient to patient, and there is a lack of reliable prognostic markers. In order to identify genes involved in tumor progression, gene expression profiling was performed on tumor specimens. Samples comprised 18 primary tumors, 17 lymph node (LN) metastases, and seven liver metastases from a total of 19 patients. Patients were grouped according to clinical data and histopathology into indolent or progressive course. RNA was subjected to a spotted oligo microarray and B-statistics were performed. Differentially expressed genes were verified using quantitative real-time PCR. Self-organizing maps demonstrated three clusters: 11 primary tumors separated in one cluster, five LN metastases in another cluster, whereas all seven liver metastases, seven primary, and 12 LN metastases formed a third cluster. There was no correlation between indolent and progressive behavior. The primary tumors with Ki67 >5%, with low frequency of the carcinoid syndrome, and a tendency toward shorter survival grouped together. Primary tumors differed in expression profile from their associated LN metastases; thus, there is evidence for genetic changes from primary tumors to metastases. ACTG2, GREM2, REG3A, TUSC2, RUNX1, TPH1, TGFBR2, and CDH6 were differentially expressed between clusters and subgroups of tumors. The expression profile that assembles tumors as being genetically similar on the RNA expression level may not be concordant with the clinical disease course. This study reveals differences in gene expression profiles and novel genes that may be of importance in midgut carcinoid tumor progression.

[177Lu-DOTA 0-Tyr 3]-octreotate treatment in patients with disseminated gastroenteropancreatic neuroendocrine tumors: the value of measuring absorbed dose to the kidney

BACKGROUND

Peptide receptor radiation therapy (PRRT) using [(177)Lu-DOTA(0)-Tyr(3)]-octreotate is a new, promising option for treatment of disseminated gastroenteropancreatic neuroendocrine tumors (GEPNETs).

METHODS

During 2006-2008, 26 patients with disseminated GEPNETs were treated with (177)Lu-octreotate. Radiologic response (RECIST), biochemical response [plasma chromogranin-A (P-CgA)], hematologic toxicity [Common Toxicity Criteria (CTC)], absorbed dose to the kidneys (conjugate view method), and glomerular filtration rate (GFR) were analyzed.

RESULTS

(177)Lu-octreotate (8 GBq) was given one to five times (median = 3) with a 6-week interval between each. Sixteen of the 26 patients were evaluated radiologically; 6 (38%) had partial response (PR), 8 (50%) had stable disease (SD), and 2 (13%) had progressive disease (PD). Seventeen of the 26 patients were evaluated biochemically; 6 (35%) showed a >or=30% decrease, 8 (47%) showed a >or=20% increase, and 3 (18%) showed neither a >or=30% decrease nor a >or=20% increase. The mean absorbed dose to the kidneys was 24 Gy. With a dose limit of 27 Gy to the kidneys, 10 patients did not receive the planned four treatments, while four patients had the potential to receive additional treatment. A significant reduction (p = 0.0013) of GFR was observed at follow-up. Three patients experienced CTC grade 3 hematologic toxicity.

CONCLUSIONS

By using the absorbed dose to the kidneys as a limiting factor, treatment with (177)Lu-octreotate can be individualized, e.g., overtreatment can be avoided and patients with the potential to receive additional treatment can be identified. Further studies are needed to define tolerance doses to the kidneys so that treatment can be optimized.

Development of a highly sensitive and specific carboxy-terminal human pancreastatin assay to monitor neuroendocrine tumor behavior

OBJECTIVE

Pancreastatin is a fragment of the chromogranin A (CgA) molecule. Existing pancreastatin assays, which depend on antibodies that cross-react in varying percents with the larger prohormone, may lack sensitivity and specificity to detect small changes in neuroendocrine tumor volume.

METHODS

We developed a highly specific, sensitive pancreastatin assay. The antibody used recognizes the carboxyl terminal of the peptide hormone and was raised against a 17-amino acid porcine pancreastatin fragment with high homology with the carboxy-terminal amino acids 286-301 of the human CgA.

RESULTS

Our assay measures more than 95% of circulating pancreastatin levels; has little or no cross-reactivity with CgA, even at plasma concentrations of 1000 ng/mL; and can detect pancreastatin levels of 17 pg/mL. Interassay reproducibility for the pancreastatin radioimmunoassay was determined from results of 3 quality control pools in 15 consecutive assays. Coefficients of variation for low, medium, and high pancreastatin levels were less than 20%. The sensitivity of serial pancreastatin assays to detect early liver tumor activity was demonstrated in 2 patients with slowly progressive neuroendocrine tumors and in patients undergoing surgical cytoreduction.

CONCLUSIONS

This highly specific, sensitive pancreastatin assay can detect small changes in liver tumor progression and is up to 100-fold more sensitive and specific than CgA assays in the United States.

Chromogranin A--biological function and clinical utility in neuro endocrine tumor disease

BACKGROUND

Neuroendocrine tumors (NETs) are a form of cancer that differ from other neoplasia in that they synthesize, store, and secrete peptides, e.g., chromogranin A (CgA) and amines. A critical issue is late diagnosis due to failure to identify symptoms or to establish the biochemical diagnosis. We review here the utility of CgA measurement in NETs and describe its biological role and the clinical value of its measurement.

METHODS

Literature review and analysis of the utility of plasma/serum CgA measurements in NETs and other diseases.

RESULTS

CgA is a member of the chromogranin family; its transcription and peptide processing are well characterized, but its precise function remains unknown. Levels are detectable in the circulation but vary substantially (approximately 25%) depending on which assay is used. Serum and plasma measurements are concordant. CgA is elevated in approximately 90% of gut NETs and correlates with tumor burden and recurrence. Highest values are noted in ileal NETs and gastrointestinal NETs associated with multiple endocrine neoplasia type 1. Both functioning and nonfunctioning pancreatic NETs have elevated values. CgA is more frequently elevated in well-differentiated tumors compared to poorly differentiated NETs. Effective treatment is often associated with decrease in CgA levels. Proton pump inhibitors falsely increase CgA, but levels normalize with therapy cessation.

CONCLUSIONS

CgA is currently the best available biomarker for the diagnosis of NETs. It is critical to establish diagnosis and has some utility in predicting disease recurrence, outcome, and efficacy of therapy. Measurement of plasma CgA is mandatory for the effective diagnosis and management of NET disease.

Proceedings of the IASLC International Workshop on Advances in Pulmonary Neuroendocrine Tumors 2007

The International Association for the Study of Lung Cancer, (IASLC) International Congress on Advances in Pulmonary Neuroendocrine Tumors was a two-day meeting held at the Royal Brompton Hospital in London, United Kingdom on the thirteenth and forteenth of December 2007. The meeting was led by 14 member international faculty-in the disciplines of pathology, surgery, medicine, oncology, endocrinology, nuclear medicine, diagnostic imaging, and biostatistics. The aims were twofold, as an educational meeting, and to develop the IASLC International Pulmonary Neuroendocrine Tumors Registry. The meeting highlighted the difference in presentation of the tumors, management options for early and advanced stage disease including the use of novel agents and approaches. The need, process, and approach to an International Registry of Pulmonary Neuroendocrine Tumors were emphasized. International collaboration to develop a retrospective registry, prospective data collection, virtual tissue bank, and collaborative clinical trials were universally agreed as the best way to advance our understanding and treatment of these rare tumors.

Neuroendocrine tumors of the diffuse neuroendocrine system

PURPOSE OF REVIEW

Neuroendocrine tumors (previously referred to as carcinoids) are ill-understood, enigmatic malignancies that, although slow-growing compared with adenocarcinomas, can behave aggressively. In 2004, they comprised 1.25% of all malignancies; their incidence is increasing by approximately 6% per year. The present review provides an overview on neuroendocrine tumors and focuses on general features and current diagnostic and therapeutic options.

RECENT FINDINGS

Neuroendocrine tumors may present a considerable diagnostic and therapeutic challenge as their clinical presentation is nonspecific and usually late, when metastases are already evident. Topographic localization is by computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, whole-body positron emission tomography or endoscopy/ultrasound. Bronchoscopy is useful to verify the diagnosis when lesions are located centrally in the bronchi. No curative treatment except for radical surgery (almost never feasible) exists. Palliative and symptomatic treatment is based on surgical debulking, tumor embolization, and biotherapy with somatostatin analogues. Chemotherapy and radiotherapy are usually ineffective, but novel drugs such as tyrosine kinase receptor inhibitors show promising results in phase II clinical studies.

SUMMARY

Tumors of the diffuse neuroendocrine system represent a significant and increasing clinical problem, and there is a need to develop both early diagnostic tests as well as to establish targeted therapeutic strategies.

[Effective treatment of a hormonally inactive carcinoid tumour with somatostatin analogues: application of serum chromogranin-A for clinical follow-up]

INTRODUCTION

Hormonally inactive carcinoids represent a significant proportion of all carcinoids tumours. Classical biochemical and hormonal parameters are not suitable for the diagnosis and follow-up of these tumours. However, the tumour marker chromogranin A that is characteristic for several neuroendocrine tumours and secreted by the majority of these tumours as well, may offer a better means of diagnosis and follow-up. Somatostatin receptors are expressed by hormonally inactive carcinoids and the presence of these receptors has important diagnostic and therapeutic consequences.

CASE REPORT

The authors present the history of a patient with a hormonally inactive bronchial carcinoid tumour. After surgical removal of the bronchial carcinoid, liver metastases developed which were found to be somatostatin receptor positive. Somatostatin analogue treatment was introduced, followed by Yttrium-isotope labelled somatostatin analogue therapy. Serum chromogranin A was elevated before somatostatin treatment, and gradually decreased in parallel with therapy. The size of liver metastases remained unchanged during treatment.

CONCLUSIONS

Chromogranin A can be efficiently applied for the clinical follow-up of hormonally inactive carcinoid tumours. Somatostatin analogues may be effective for preventing tumour progression not only in hormone-secreting but also in hormonally inactive carcinoid tumours.

Extended octreotide suppression test to determine hormone responsiveness of multiple type I gastric carcinoid tumors

A 70-year-old man was found to have at least 12 type I gastric carcinoids and microcarcinoidosis. We performed an extended octreotide suppression test to determine if the tumors were gastrin-dependent and would likely regress after antrectomy. He was given an octreotide infusion at 12.5-25 mcg/h for 86 hr followed by depot octreotide 20 mg intramuscularly every four weeks for eight months. Fasting serum gastrin and chromogranin A levels were measured, and endoscopy with biopsies was performed before and after the infusion and at five months and eight months. Total RNA was extracted for quantitation of histidine decarboxylase mRNA using real-time PCR. Fasting serum gastrin decreased from 306 pg/ml pretreatment to 31 pg/ml at the end of infusion and 115 pg/ml at eight months. Chromogranin A decreased from four to six times the upper limit of normal to normal. Tissue histidine decarboxylase mRNA decreased 50-fold. At eight months, only a few diminutive nodules were present on endoscopy. These results demonstrated that the carcinoid tumors in this patient were under neuroendocrine control and were expected to respond to antrectomy.

Goblet cell carcinoid tumors (adenocarcinoid) of the appendix

PURPOSE

Goblet cell appendiceal carcinoids represent rare tumors that exhibit histologic features of both adenocarcinomas and neuroendocrine tumors. We present the long-term results of a series of 15 patients, focusing on clinical manifestations, diagnosis, and management.

METHODS

Eight male and seven female patients (median age, 52.8 years) were included. Final diagnosis was confirmed by histology. Patients were evaluated clinically, biochemically, and radiologically every four months. Median follow-up was 30 months.

RESULTS

The majority of patients (7/15) presented with symptoms compatible with acute appendicitis. Right hemicolectomy was performed in all except one, who subsequently developed metastases. Three patients had metastases at previous diagnosis. Plasma chromogranin-A was slightly elevated in two of them, while urinary 5-hydroxy-indol-acetic acid was normal. (111)Indium-labeled octreotide scintigraphy was positive only in two of the four patients with metastases. Ki67 index was greater than 20 percent in all of them, while in only one with local tumor. Combination chemotherapy with either cisplatin plus etoposide or with 5-fluorouracil, cisplatin, and streptozotocin was administered to all patients with metastases resulting in temporary stabilization of disease. Twelve patients are alive, while three died of their disease 9, 13, and 14 months after diagnosis.

CONCLUSIONS

The diagnostic value of chromogranin-A, urinary 5-hydroxy-indol-acetic acid, and (111)Indium-labeled octreotide scintigraphy seems to be limited in these tumors. Ki67 index appears to predict tumor behavior. Right hemicolectomy may reduce the risk of developing metastases. Chemotherapy may have efficacy in metastatic disease, however, more data are required to determine this and the optimal regimen.

Biochemistry of neuroendocrine tumours

Several circulating or urinary tumour markers can be used for the diagnosis and follow-up of functioning and clinically non-functioning neuroendocrine tumours of the pancreatic islet cells and intestinal tract. Among the specific tumour markers are serotonin and its metabolites--e.g. 5-hydroxyindoleacetic acid (5-HIAA)--in carcinoid tumours and the carcinoid syndrome, insulin and its precursors or breakdown products in insulinoma, and gastrin in gastrinoma. Plasma vasointestinal polypeptide (VIP) determinations have been used in the diagnosis of VIPoma, plasma glucagon for glucagonoma, and serum somatostatin for somatostatinoma. Among the tumour-non-specific markers are: chromogranins, neuron-specific enolase (NSE), alpha-subunits of the glycoprotein hormones, catecholamines, pancreatic polypeptide (PP), ghrelin and adrenomedullin.

Processing-independent quantitation of chromogranin a in plasma from patients with neuroendocrine tumors and small-cell lung carcinomas

BACKGROUND

Most neuroendocrine tumors express chromogranin A (CgA). The posttranslational processing of neuroendocrine proteins such as CgA is often specific for the individual tumor. To cope with this variability and improve tumor diagnosis, we developed a processing-independent analysis (PIA) method to measure the total CgA product.

METHODS

For PIA, samples underwent trypsin treatment followed by measurement of CgA by the "CgA(340-->)" assay, in which the antiserum binds an epitope starting at amino acid 340 of CgA and including amino acid residues located in the C-terminal direction. The diagnostic accuracy of the CgA PIA and 3 sequence-specific assays for CgA were evaluated on plasma samples from patients with neuroendocrine tumors and small-cell lung carcinomas. Furthermore, we investigated whether the CgA plasma concentrations correlated with the tumor burden.

RESULTS

Size-exclusion chromatography of plasma showed that CgA immunoreactivity mainly consisted of high-molecular-weight forms, indicating that neuroendocrine tumors may secrete large amounts of poorly processed CgA. Accordingly, trypsination of plasma from 54 patients with neuroendocrine tumors or small-cell lung carcinomas increased the CgA(340-->) immunoreactivity up to 500-fold. Both the CgA(340-->) assay and the PIA measured significantly higher plasma concentrations in patients with very extensive disease than in patients with less widespread disease. The diagnostic sensitivity was 0.91 when using the CgA(340-->) assay and 0.82 using the CgA PIA.

CONCLUSION

The CgA(340-->) assay and CgA PIA are both useful for diagnosis of neuroendocrine tumors and small-cell lung carcinomas and both assays correlate with tumor burden.

Biomarkers predict outcomes following cytoreductive surgery for hepatic metastases from functional carcinoid tumors

BACKGROUND

Cytoreductive therapy for metastatic carcinoid provides symptomatic relief and improvement in overall survival. We evaluated whether CgA and 5HIAA could predict symptomatic relief and control of disease progression after cytoreductive surgery.

METHODS

We retrospectively reviewed 70 patients who underwent cytoreductive surgery for neuroendocrine hepatic metastases between 1996 and 2005. Twenty-two patients had pre and post-operative CgA and/or 5HIAA levels measured. Reduction of biomarkers following cytoreduction was correlated with patient symptoms and progression of disease following surgery.

RESULTS

Our study consisted of 14 males and 8 females with a mean age of 55 (+/-12 years). Median follow-up was 18 months (range 5-64 months). Six patients (26.1%) had complete (R0) cytoreduction, while 4 (17.4%) and 13 (56.5%) had microscopic (R1) and gross (R2) disease remaining. All patients reported improvements in their symptoms, with 12 (54.5%) reporting complete resolution (CR) and 10 (45.5%) reporting partial resolution (PR). Reduction of CgA of >or= 80% was highly predictive of complete resolution of symptoms (P = 0.007) and stabilization of disease (P = 0.034). Reduction of 5HIAA levels of >or= 80% (or normalization) was predictive of symptomatic relief, but not progression of disease (P = 0.026 and P = 0.725). Five of six patients who had R0 resections had CR and were free of disease at last follow-up (median 24.5 months, range: 11-48, P = 0.002).

CONCLUSIONS

We conclude that >or= 80% reduction in CgA level following cytoreductive surgery for carcinoid tumors is predictive of subsequent symptom relief and disease control. Substantial reduction in CgA is associated with improved patient outcomes, even after incomplete cytoreduction.

Validation of serum versus plasma measurements of chromogranin a levels in patients with carcinoid tumors: lack of correlation between absolute chromogranin a levels and symptom frequency

OBJECTIVE

Chromogranin A (CGA) levels are used to confirm the diagnosis and monitor the course of patients with neuroendocrine tumors. Chromogranin A levels are significantly reduced when patients are acutely treated with octreotide; however, limited data are available that correlates octreotide long-acting repeatable (LAR) dose or steady state octreotide blood levels to the absolute value of serum or plasma CGA.

METHODS

Plasma, serum, and clinical information on carcinoid syndrome symptoms were collected anonymously from 40 patients treated with long-term octreotide LAR therapy for carcinoid syndrome.

RESULTS

We found a strong positive linear relationship exists between serum and plasma CGA levels (r = 0.9858, P < 0.0001). No correlation existed between plasma octreotide levels or LAR dose and the static, absolute plasma/serum CGA levels. Although, higher mean CGA values were seen in the group whose diarrhea was "not under optimal control" than for the group "under optimal control," these results did not reach statistical significance (P = 0.24). Contrary to our hypotheses, a statistically significant inverse relationship was found between the frequency of flushing and the CGA levels (P = 0.0372). Higher mean CGA values were observed in the "under optimal control" group with flushing symptoms.

CONCLUSIONS

Either serum or plasma can be used to measure CGA levels. Absolute (static) CGA levels do not positively correlate with symptom intensity during LAR therapy. Dynamic (serial) measurements of CGA are necessary to monitor the effectiveness of medical or surgical therapy.

Gastrointestinal carcinoids: the evolution of diagnostic strategies

Carcinoid tumors are rare, often insidious neoplasms arising from neuroendocrine cells. The majority arise in the gastrointestinal system, and are often incidentally found during investigation, although some may present as an emergency bleed or perforation. The prosaic symptoms of flushing, diarrhea, and sweating are often overlooked; thus, the diagnosis is usually much delayed and the tumor is advanced at presentation. This diagnostic delay renders effective management difficult and adversely affects outcome. This overview provides a current assessment of the evolution of the diagnostic techniques available to establish an accurate biochemical (5-hydroxyindole-3-acetic acid and chromogranin A) and topographic diagnosis (octreoscan, radio-labeled metaidobenzylguanidine, computerized tomography, magnetic resonance imaging, positron emission tomography, enteroclysis, endoscopic ultrasound, enteroscopy, capsule endoscopy, and angiography) of carcinoid tumors. The utility and shortcomings of the respective modalities available are evaluated. Although considerable advances have been made in establishing the diagnosis of carcinoid tumors and in defining the topography of metastatic disease, the major limitation is the inability to establish an early and timely diagnosis before the advent of metastatic disease.

IFN-beta is a highly potent inhibitor of gastroenteropancreatic neuroendocrine tumor cell growth in vitro

IFN-alpha controls hormone secretion and symptoms in human gastroenteropancreatic neuroendocrine tumors (GEP-NET) but it rarely induces a measurable tumor size reduction. The effect of other type I IFNs, e.g., IFN-beta, has not been evaluated. We compared the antitumor effects of IFN-alpha and IFN-beta in BON cells, a functioning human GEP-NET cell line. As determined by quantitative reverse transcription-PCR analysis and immunocytochemistry, BON cells expressed the active type I IFN receptor mRNA and protein (IFNAR-1 and IFNAR-2c subunits). After 3 and 6 days of treatment, IFN-beta significantly inhibited BON cell growth in a time- and dose-dependent manner. IC50 and maximal inhibitory effect on day 6 were 8 IU/mL and 98%, respectively. In contrast, the effect of IFN-alpha resulted significantly in a less potent effect (IC50: 44 IU/mL, maximal inhibition: 26%). IFN-alpha induced only cell cycle arrest, with an accumulation of the cells in S phase. IFN-beta, apart from a more potent delay in S-G2-M phase transit of the cell cycle, also induced a strong stimulation of apoptosis, evaluated by flow cytometry (Annexin V and 7-AAD) and measurement of the DNA fragmentation. Besides, only IFN-beta severely suppressed chromogranin A levels in the medium from BON cells after 6 days of treatment. In conclusion, IFN-beta is much more potent, compared with IFN-alpha, in its inhibitory effect on GEP-NET cell proliferation in vitro through the induction of apoptosis and cell cycle arrest. Further studies are required to establish whether IFN-beta has comparable potent tumor growth inhibitory effects in vivo.