Epidemiology of neuroendocrine tumours

Anatomic and functional imaging of metastatic carcinoid tumors

Carcinoid tumors are a fascinating group of neuroendocrine neoplasms that develop either sporadically or as part of an inheritable syndrome. Many tumors arise in the bronchopulmonary or gastrointestinal tract, but a neuroendocrine tumor can arise in almost any organ. The tumors have varied malignant potential depending on the site of their origin, and the clinical manifestations often are nonspecific. Metastases may be present at the time of diagnosis, which often occurs at a late stage of the disease. Imaging plays a pivotal role in the localization and staging of neuroendocrine tumors and in monitoring the treatment response. Imaging is often challenging, and a combination of anatomic and functional techniques is usually required, depending on the tumor type and location. Techniques include ultrasonography, barium studies, endoscopy, computed tomography, magnetic resonance imaging, somatostatin receptor scintigraphy, iobenguane scintigraphy, and, in select cases, positron emission tomography. Coregistration of structural and functional images is often of incremental value for accurate localization of the primary tumor and any meta-static disease. Radiologists must understand the contribution of each imaging modality in the assessment of different neuroendocrine tumors. In addition, knowledge of the optimal technique for each radiologic and radionuclide imaging examination is essential. Familiarity with the protean imaging appearances of both primary and metastatic disease is essential for accurate staging, treatment monitoring, and surveillance. Finally, an understanding of the wide variety of treatment options for patients with carcinoid tumors is vital for optimal management.

Ghrelin in neuroendocrine organs and tumours

Ghrelin is a 28 amino-acid hormone with multiple functions. It is predominantly produced by the stomach but has also been detected in other organs, including the small intestine, pancreas, hypothalamus and pituitary, as well as in the immune system and almost every other normal human tissue examined. It is also present in neuroendocrine tumours, pituitary adenomas, endocrine tumours of the pancreas, breast tumours, and thyroid and medullary thyroid carcinomas. Ghrelin is a brain-gut peptide with growth hormone-releasing and appetite-inducing activities, and is the endogenous ligand of the G protein-coupled growth hormone secretagogue receptor (GHS-R). In this review we comprehensively summarize the available data regarding (a) the expression of ghrelin and the GHS-R in normal endocrine tissues and in pituitary adenomas and neuroendocrine tumours, (b) the levels of circulating ghrelin in patients with pituitary adenomas and neuroendocrine tumours and (c) the effects of ghrelin administration in these patients on the levels of other hormones and on the rate of proliferation of the tumour. It is clear that ghrelin has many more functions and is involved in many more processes than was initially postulated, and its endocrine, paracrine and autocrine effects play a role in its physiological and pathophysiological functions.

Detection of small-bowel neuroendocrine tumors by video capsule endoscopy

OBJECTIVES

Carcinoid tumors are the most common GI neuroendocrine tumors (NET). They often originate in the small intestine. The primary tumor is often difficult to locate, and resection in an early phase is recommended to prevent complications. This study evaluated the value of videocapsule endoscopy (VCE) in the detection of small-intestinal primary carcinoid tumor.

DESIGN

Prospective descriptive study.

SETTING

Tertiary referral center.

PATIENTS

Twenty consecutive patients (13 men, 7 women; 60.5 +/- 9.3 years) with metastatic NET of unknown primary tumor.

INTERVENTIONS

All patients underwent CT, enteroclysis, nuclear imaging, and VCE of the small bowel.

RESULTS

CTs and enteroclysis did not detect a primary small-intestinal carcinoid tumor. Nuclear imaging demonstrated abnormalities in the abdominal area in 13 patients but was unable to relate this to an intestinal localization in any patient. VCE revealed a small-intestinal tumor in 9 patients. Three other patients showed external compression and erosions. At surgery, 5 patients had a small-intestinal carcinoid tumor, and, in 2 patients, a small-intestinal ischemic segment was present.

LIMITATIONS

The number of false-positive VCE findings was not clear, because not all patients underwent surgery. The absence of abnormalities at VCE in patients with abnormalities at nuclear imaging might be related to the presence of carcinoid tumor restricted to the mesenterium or to a false-negative VCE.

CONCLUSIONS

VCE had a high diagnostic yield of 45% for identification of primary small-intestinal carcinoid tumors. Although nuclear imaging had a comparable diagnostic yield, it could not differentiate between intestinal and mesenterial localization of the carcinoid.

Liver transplantation for gastroenteropancreatic neuroendocrine cancers: Defining selection criteria to improve survival

Liver transplantation for gastroenteropancreatic neuroendocrine cancer (GEP) is controversial. The aim of this study was to assess patient outcomes after liver transplantation for hepatic metastases from GEP. Medical records of patients who underwent liver transplantation for GEP were reviewed. Immunohistochemistry for assessing the Ki67 proliferation index was performed on explanted liver tissue. Nineteen patients who underwent liver transplantation had a mean follow-up of 22 months with a range of 0 to 84 months. There was 1 intraoperative death, and 3 patients had disease recurrence after liver transplantation leading to death in 1 patient. Overall estimated 1-year survival for 17 patients included in the treatment protocol (mean follow-up, 15 months) was 87% with an estimated 1-year recurrence-free rate (conditional on survival) of 77%. Three of 11 patients with pancreatic islet cell GEP developed disease recurrence, whereas all 8 patients with carcinoid GEP remain free of disease. Analysis of the Ki67 proliferation index in 18 patients did not differentiate those with recurrence from those without disease recurrence. In conclusion, liver transplantation for patients with hepatic metastases from GEP is a viable therapeutic option in highly selected patients.

Endocrine tumors of the ileum: factors correlated with survival

AIM

To evaluate the most important factors correlated with survival in patients with endocrine tumors of the ileum, both at the time of diagnosis and during the follow-up period.

METHODS

Fifty-nine patients with ileal endocrine tumors diagnosed in our institution between 1990 and 2004 were studied.

RESULTS

The study included 36 men (61%) and 23 women (39%). The median age of the patients at the time of diagnosis was 61.4 (range 18-83) years. The median follow-up period was 71.9 (range 5-287) months. Forty patients (67.8%) were still alive at the end of the study; the median survival time was 172 months, and the 5-year survival rate was 78.9%. By univariate analysis, the survival rate was significantly related to female sex (p = 0.024) and flushing alone (p = 0.028) and associated with diarrhea at diagnosis (p = 0.015), weight loss at diagnosis (p = 0.038), Ki-67 level (p = 0.025), stage of disease at diagnosis (p = 0.012), presence of liver metastases at follow-up (p = 0.005), presence of diffuse metastases at diagnosis (p = 0.005) and at follow-up (p = 0.007), and type of surgical approach (overall: p = 0.018; not operated vs. radical surgery: p = 0.008; not operated vs. palliative surgery: p = 0.045). Using multivariate analysis, only female gender (p = 0.012) and the presence of liver metastases at follow-up (p = 0.004) were significantly related to survival.

CONCLUSION

In the present study, female gender and the appearance of liver metastases at follow-up seem to be the main conditions which determine the poor prognosis of patients with ileal endocrine tumors.

Long-term clinical outcome of somatostatin analogues for treatment of progressive, metastatic, well-differentiated entero-pancreatic endocrine carcinoma

BACKGROUND

Knowledge of factors able to predict the clinical outcome of homogenous series of entero-pancreatic endocrine tumours treated with somatostatin analogues is poor. This study was aimed at identifying predictors for efficacy of somatostatin analogues at inhibiting tumour growth and modifying patients' survival during long-term follow-up.

PATIENTS AND METHODS

31 patients with entero-pancreatic well-differentiated endocrine carcinoma received long-acting somatostatin analogues. All had progressive, metastatic disease (87% liver metastases, 38.7% distant extra-hepatic metastases).

RESULTS

Response rate after 6 months of treatment was 45.2% (all disease stabilisation: 27.8% of pancreatic vs. 81.8% of intestinal tumours, P = 0.007). The predictors for non-response were: pancreatic tumour (OR 5.8), no previous surgery (OR 6.7), and the presence of distant extra-hepatic metastases, the latter being also confirmed by multivariate analysis (OR 10.0). Responders maintained stabilisation for 26.5 months, and none died during follow-up. Different survival curves were observed for patients, responding at 6 months compared to non-responders (P = 0.004), 3-year survival rate being 100% and 52.3%, respectively.

CONCLUSIONS

Distant extra-hepatic metastases are the major predictor of poor efficacy of somatostatin analogues in progressive, metastatic, well-differentiated entero-pancreatic endocrine carcinomas. Patients achieving response after 6 months of treatment, maintain it throughout a long-term follow-up. Non-responders after 6 months of treatment, have a worse survival, and should be considered for alternative treatments.

Metastatic carcinoid tumors: a clinical review

Carcinoid tumors are neuroendocrine tumors derived from enterochromaffin cells, which are widely distributed in the body. They can originate from any location in the body, but they are traditionally described as originating from the foregut, midgut, and hindgut. Although the overall incidence of carcinoid tumors appears to have increased in the past decades, the prognosis for patients with metastatic carcinoid tumors has improved during the last decade. Due to longer survival times, complications, such as carcinoid heart disease, and new metastatic patterns, like skin and bone metastases, may become more important features of carcinoid disease. Therapy focused on these complications should be part of the management. Combining new diagnostic and treatment modalities in metastatic carcinoid patients may result in better quality of life and longer survival times. The increasing number of therapeutic options and diagnostic procedures requires a multidisciplinary approach, with decisions made in multidisciplinary meetings focused on "tailor-made" therapy based on patients' specific conditions. Because carcinoid tumors are uncommon, effort should be made to treat these patients in specialized centers and for these centers to join together in multicenter studies.

Secretagogin is a novel marker for neuroendocrine differentiation

Our previous microarray-based studies identified secretagogin to be highly expressed in normal colon mucosa compared to basal expression in colon adenocarcinomas. The aim of this study was to analyze the differential expression of secretagogin in normal mucosa, adenocarcinomas, and neuroendocrine tumors. Western blotting, immunohistochemistry, immunofluorescence microscopy and ELISA were applied. Western blot analysis detected a 32-kDa secretagogin band in samples from normal mucosa. Immunohistochemical analyses on tissue specimens showed that secretagogin is exclusively expressed in neuroendocrine cells and nerve cells in normal mucosa of the digestive tract. Tissues adjacent to benign hyperplasic polyps and adenomas showed a decreased number of secretagogin-expressing neuroendocrine cells. Secretagogin co-localized with neuroendocrine markers (chromogranin A, neuron-specific enolase, synaptophysin) in neuroendocrine cells in crypts of normal mucosa, and in tumor cells of carcinoids. Secretagogin was strongly expressed in the cytosol and the nucleus of 19 well-differentiated neuroendocrine carcinoids and carcinoid metastases, as well as in neuroendocrine tumors from the lung, pancreas and adrenal gland. Secretagogin was detected in plasma from carcinoid patients with distant metastasis. Combined immunohistochemical analysis of secretagogin and FK506-binding protein 65, a protein de novo synthesized in adenocarcinomas, distinguished well-differentiated carcinoids, adenocarcinoids and undifferentiated carcinomas. We conclude that secretagogin is a novel marker for neuroendocrine differentiation.