A 50-year analysis of 562 gastric carcinoids: small tumor or larger problem?

Laparoscopic antrectomy for the treatment of type I gastric carcinoid tumors

BACKGROUND

While the optimal treatment for type I gastric carcinoid tumors remains controversial, there is evidence to suggest that in multifocal disease, antrectomy may not only control local disease but also may lead to enterochromaffin-like cell (ECL) hyperplasia regression compared to medical and endoscopic treatments.

MATERIALS AND METHODS

A single institution retrospective review of eight consecutive patients with multifocal type I gastric carcinoid tumor patients with no evidence of metastatic disease was performed from 2005 to 2006. All of these patients underwent laparoscopic antrectomy with Billroth II reconstruction. Patients' preoperative gastrin, chromogranin A levels, and biopsy and surgical specimen slides were compared with postoperative laboratory and biopsy slides. Pathology slides were reanalyzed by a blinded pathologist from our institution for evidence of tumor and ECL hyperplasia regression.

RESULTS

All patients tolerated the procedure well with no reoperations or mortalities. Six of eight patient complained of mild reflux which was treated medically. One of eight had a mild wound infection which resolved with a course of cephalexin. Gastrin levels significantly decreased (98.9%) in all patients (P = 0.001). Furthermore, chromogranin A levels also significantly decreased (81.4%). Eight of eight patients showed no evidence of carcinoid tumor after surgery at mean biopsy follow-up of 17 mo (range 2-35 mo), however there was ECL hyperplasia after resection. Four of eight patients (50%) showed regression of ECL hyperplasia on postop biopsy, while the remaining four of eight showed no evidence of regression.

CONCLUSIONS

This is the largest case series to investigate the surgical, clinical, and histologic outcomes of laparoscopic antrectomy in type I gastric carcinoid. Our data suggest that laparoscopic antrectomy is a safe and minimally invasive approach to treat nonmetastatic type I gastric carcinoid. All patients had no evidence of gross or microscopic disease at follow-up biopsy and almost half had regression of ECL hyperplasia at follow-up suggesting that antrectomy may be sufficient to prevent tumor recurrence. However, continued regular endoscopic surveillance and medical follow-up of patients with ECL hyperplasia are recommended.

Corpus predominant gastritis: what does it mean?

PURPOSE OF REVIEW

To summarize this year's relevant literature on the causes and mechanisms of autoimmune gastritis.

RECENT FINDINGS

It is increasingly recognized that parietal cell antibodies, previously assumed exclusive to autoimmune gastritis, are associated with Helicobacter pylori infection. Successful H. pylori eradication with antibiotic treatment decreases antiparietal cell antibodies. Interestingly, vitamin B(12) deficiency, previously associated with autoimmune gastritis, is increasingly described in the elderly, irrespective of H. pylori status. Autoimmune gastritis that mostly affects patients of Scandinavian descent, was reported this year from China, and corpus predominant gastritis (autoimmune associated) was reported from Japan. It is difficult to evaluate the role played by genetics, increased use of proton pump inhibitors, and H. pylori infection, as current patient work-up does not regularly include screening for parietal cell and intrinsic-factor antibodies. As these clinicopathologic changes are seen in both H. pylori-positive patients, and in H. pylori-naïve patients, the debate continues for mechanisms involved in H. pylori-naïve patients.

SUMMARY

The clinical features commonly associated with autoimmune gastritis are increasingly seen in the elderly, irrespective of H. pylori status. Though some patients are genetically predisposed, long-term proton pump inhibitor use increases the prevalence of clinicopathologic features irrespective of genetic tendency.

Insights into the future of gastric acid suppression

The development of effective acid-suppression therapy (particularly PPIs) has revolutionized the treatment of acid-related diseases. Despite the overall effectiveness of these agents, they have some shortcomings, including a delayed onset of action, incomplete acid suppression in the majority of patients, and the need for ingestion before a meal to achieve maximal efficacy. Attempts to overcome these issues have included the development of isomeric PPIs (such as esomeprazole), alterations in drug delivery (such as delayed-release dexlansoprazole), and combined therapy with nonenterically coated PPIs and antacids (such as 'naked' omeprazole combined with sodium biocarbonate). Other acid-suppression agents in development or in late-phase trials include potassium-competitive acid blockers, new histamine receptor 2 antagonists, and gastrin antagonists. Although these agents could potentially achieve complete gastric acid suppression, risks may be associated with this level of suppression, including enteric infections and malabsorption of nutrients such as vitamin B(12), iron and calcium. This Review provides an update on the status of acid-suppression therapy and discusses directions for future research.

En-bloc resection of multiple type 1 gastric carcinoid tumors by endoscopic multi-band mucosectomy

BACKGROUND AND AIM

Gastric carcinoid tumors are rare but increasing in incidence. Current recommendations suggest endoscopic resection for type I carcinoids found in the stomach, however reports of incomplete resection have led to difficulty planning future management. Our purpose was to describe the application of the endoscopic multi-band mucosectomy (MBM) device to achieve en-bloc resection of multiple gastric carcinoid tumors.

METHODS

Over a 30-month period (June 2006-January 2009) eight patients attending for endoscopic assessment of gastric carcinoid tumors were identified at two tertiary referral centers. Patients underwent endoscopic resection of the carcinoids with an MBM device. En-bloc specimens underwent histological evaluation for identification and tumor resection margins. Patients with type I carcinoids were subsequently enrolled in an endoscopic follow-up program.

RESULTS

A total of 34 gastric carcinoid tumors were removed from eight patients. On histological analyses seven out of eight patients were diagnosed with type I tumors. In the remaining patient a single, sporadic (type III) gastric carcinoid was diagnosed. No complications of severe bleeding or perforation occurred. All specimens were shown to have clear deep and peripheral histological resection margins.

CONCLUSION

Complete 'en-bloc' endoscopic resection of multiple 'type I' gastric carcinoid tumors can be safely and easily performed with an MBM technique.

Gastric carcinoids: between underestimation and overtreatment

Gastric carcinoids (GCs), which originate from gastric enterochromaffin-like (ECL) mucosal cells and account for 2.4% of all carcinoids, are found increasingly in the course of upper gastrointestinal tract endoscopy. Current nosography includes those occurring in chronic conditions with hypergastrinemia, as the type 1 associated with chronic atrophic gastritis, and the type 2 associated with Zollinger-Ellison syndrome in multiple endocrine neoplasia type 1, and type 3, which is unrelated to hypergastrinemia and is frequently malignant, with distant metastases. The optimal clinical approach to GCs remains to be elucidated, depending upon type, size and number of carcinoids. While there is agreement concerning the treatment of type 3 carcinoids, for types 1 and 2, current possibilities include simple surveillance, endoscopic polypectomy, surgical excision, associated or not with surgical antrectomy, or total gastrectomy. Moreover, the recent introduction of somatostatin analogues represents a therapeutic option of possibly outstanding relevance.

Tautomycin suppresses growth and neuroendocrine hormone markers in carcinoid cells through activation of the Raf-1 pathway

BACKGROUND

Carcinoids are neuroendocrine (NE) tumors with limited treatment options. Raf-1 pathway activation has been shown to suppress hormone production in carcinoid cells. We investigated a novel treatment for carcinoid cell growth based on pharmacologic Raf-1 activation using the compound tautomycin (TTY).

METHODS

Human carcinoid cells were treated with TTY for 48 hours. Western blot analysis was used to demonstrate Raf-1 pathway activation by phosphorylation of ERK1/2 and to determine the effect on NE tumor markers. Cellular growth was measured by methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay.

RESULTS

Treatment with TTY resulted in dose-dependent activation of the Raf-1 pathway. Furthermore, a significant decrease in NE tumor markers was seen. Importantly, TTY inhibited carcinoid cellular growth and induced the cell-cycle inhibitors p21 and p27.

CONCLUSION

TTY activates the Raf-1 pathway, limits carcinoid cell growth, and suppresses NE marker production in vitro. This new compound warrants further investigation in animal models of carcinoid cancer.

Neuroendocrine tumor epidemiology: contrasting Norway and North America

BACKGROUND

The National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program has proven to be a significant resource in US neuroendocrine tumor (NET) epidemiology. Norway also holds a robust and detailed cancer registry: the Norwegian Registry of Cancer (NRC).

METHODS

SEER NET data were compared with corresponding NRC data in the time period 1993 to 2004 to determine whether there are differences in NET epidemiology between Norway and the United States.

RESULTS

The SEER and NRC reported 17,312 and 2030 NETs, respectively. The overall Caucasian SEER NET incidence was 4.44, compared with 3.24 in the NRC. In the SEER white subset, bronchopulmonary NETs were the most common (incidence = 1.42; 32% of all NETs), compared with small intestinal NETs in the NRC (0.81; 26%). A marked increase in SEER NET incidence (37%-40%) was observed in the period 2000 to 2004, compared with 1993 to 1997; an even more pronounced increase (72%) was seen in the NRC. African Americans exhibited a remarkably high overall NET incidence of 6.50; furthermore, among African Americans, rectal NETs were most common (1.65; 27%). Small intestinal NET incidence was approximately 30% higher in men compared with women in all populations. The highest 5-year survival rates were for rectal NETs (74%-88%) in both databases, whereas prostatic NETs had the worst outcome (0%-23%). At diagnosis, NETs were localized in 27% to 46% of patients.

CONCLUSIONS

NET incidence in the US Caucasian population and in Norway is similar, but considerably higher ( approximately 50%) among African Americans. NETs have been regarded as indolent tumors; however, the 5-year survival is only approximately 55%.

Gastric carcinoid tumor in a patient with a past history of gastrointestinal stromal tumor of the stomach

Gastrointestinal stromal tumor is the most common mesenchymal tumor in the gastrointestinal tract. It may coexist with other type of cancers, and if so, the tumors usually involve the stomach. The most common associated cancers are gastrointestinal carcinomas. We report a 65-year-old woman with a history of gastric gastrointestinal stromal tumor who had undergone subtotal segmental gastrectomy. New polypoid lesions were detected on a follow-up gastroscopy one year later. The lesions were biopsied and found to be carcinoid tumors. There was serum hypergastrinemia, and type 1 gastric carcinoid tumor was diagnosed. A total gastrectomy was performed. Pathologic examination revealed both carcinoid tumors and a recurrent gastrointestinal stromal tumor.

Potential adverse effects of proton pump inhibitors

Proton pump inhibitors (PPIs) have revolutionized the management of gastroesophageal reflux disease and peptic ulcer disease over the past two decades. Among the most commonly prescribed agents worldwide, PPIs' overall safety profile is unquestionable. However, emerging evidence indicates that PPI therapy, particularly with long-term and/or high-dose administration, is associated with several potential adverse effects, including enteric infections (eg, Clostridium difficile), community-acquired pneumonia, and hip fracture, all of which have received much attention recently. We review the current data on these and other potential consequences of PPI therapy. More judicious use of PPIs (eg, administering them in no more than the minimum effective dose to older adult patients) may help to further limit the impact of some of these possible adverse effects.

Subepithelial mass lesions in the upper gastrointestinal tract

The finding of a mass lesion in the upper gastrointestinal tract at endoscopy with apparent normal overlying mucosa is common. The differential diagnosis of such lesions is broad and includes those of intramural or extramural origin. Endoscopic ultrasound provides accurate imaging of subepithelial mass lesions and characterizes them according to size, echogenicity, and origin including the histologic layer if the lesion is intramural which narrows the differential diagnosis. Endoscopic ultrasound allows a guided tissue sample to be obtained for histologic confirmation which is especially important for hypoechoic lesions arising from the 3rd or 4th echogenic layers. The purpose of this article is to review the diagnosis of the more common subepithelial mass lesions with an emphasis on endoscopic ultrasound and the subsequent management or monitoring.

Treatment of gastric carcinoids

Gastric carcinoid tumors are uncommon, but their percentage among all gastric malignancies has increased to 1.8%. Although they are most often discovered incidentally during endoscopy, gastric carcinoids can present with abdominal pain, bleeding, or symptoms related to the secretion of bioactive substances, most commonly histamine. Gastric carcinoids originate from the foregut and are derived from histamine-containing enterochromaffin-like (ECL) cells. Type I gastric carcinoid, the most common, exhibits slow growth and benign behavior. It occurs within the setting of chronic atrophic gastritis with achlorhydria-induced hypergastrinemia. Gastrin acts directly on ECL cells to induce hyperplasia, dysplasia, and, eventually, neoplasia. Type II gastric carcinoid, the least common type, occurs in patients with gastrinoma-associated multiple endocrine neoplasia syndrome-type 1 (MEN-1). The overall survival is related more to the underlying MEN-1 syndrome than to the gastric carcinoid. Rodents readily develop gastric carcinoid tumors in response to hypergastrinemia. However, in humans, other factors in addition to hypergastrinemia, such as pernicious anemia or MEN-1, must be present, implying that a genetic predisposition is necessary for the development of these tumors. Type III or sporadic gastric carcinoids exhibit a more malignant behavior, with overall 5-year survival rates of less than 50% and normal serum gastrin concentrations. Treatment of all types of gastric carcinoids is predicated upon accurate classification and staging. Radiolabeled somatostatin analogues are superior to conventional radiologic imaging techniques in detecting both primary and metastatic lesions. Treatment of choice for localized disease is excision, either endoscopically or surgically. Antrectomy, by eliminating the trophic effect of gastrin, can be useful for select type I carcinoids. Long-acting somatostatin analogues are excellent palliative agents.

Serum gastrin and chromogranin A levels in patients with fundic gland polyps caused by long-term proton-pump inhibition

OBJECTIVE

Use of proton-pump inhibitors (PPIs) causes hypergastrinemia, and it is well known that gastrin has a trophic effect on the oxyntic mucosa. Some PPI users develop fundic gland polyps. The purpose of this study was to determine whether patients developing fundic gland polyps have a more pronounced gastric hypoacidity, hypergastrinemia or increased serum chromogranin A (CgA), which is an enterochromaffin-like (ECL) cell marker.

MATERIAL AND METHODS

Five PPI users who developed multiple fundic gland polyps during PPI use were included in the study. PPI users without fundic gland polyps (n = 6) as well as healthy individuals (n = 6) were used as controls. In PPI users, we measured 24-h gastric pH, serum gastrin and CgA during one day, with standardized meals, whereas only gastrin and CgA were measured in the healthy individuals. Helicobacter pylori status was determined.

RESULTS

Gastric pH, serum gastrin and CgA did not differ significantly between PPI users with and those without fundic gland polyps. All patients with fundic gland polyps were H. pylori negative, whereas 4 out of 6 PPI users without fundic gland polyps were H. pylori positive. Fasting CgA levels were elevated in all PPI users, and CgA more than doubled during the day in all groups.

CONCLUSIONS

Fundic gland polyps induced by PPIs are not related to the level of hypergastrinemia. Serum CgA is markedly affected by meals and should be measured in samples from fasting patients.

Endocrine hyperplasia and dysplasia in the pathogenesis of gastrointestinal and pancreatic endocrine tumors

Non-neoplastic proliferative lesions of endocrine cells have been described throughout the gastrointestinal tract and pancreas. A multistep continuum from hyperplasia and dysplasia to neoplasia originally was identified and systematically defined for histamine-producing enterochromaffin-like (ECL) cells of the gastric corpus. More recently, a similar classification system was devised for gastrin (G)- and somatostatin (D)-producing cells in the duodenum. Preneoplastic lesions of the endocrine pancreas still lack a solid and widely accepted definition of a multistep growth process. Similarly, in spite of reports of carcinoid-associated endocrine cell hyperplasia, there is no systematic definition of nonneoplastic lesions of the endocrine cells of the ileum, appendix and colorectum.

Type 1 and 2 gastric carcinoid tumors: long-term follow-up of the efficacy of treatment with a slow-release somatostatin analogue

Little is known about the long-term results of treating gastric carcinoid tumors with a slow-release somatostatin analogue. We report three patients with type 1 and 2 gastric carcinoid tumors who were treated in the above mentioned way and followed for 27-50 months. In all cases, alternative endoscopic or surgical management was considered but deemed inappropriate. Treatment with a slow-release somatostatin analogue was begun in light of a favorable recent report. The result was regression or complete disappearance of macroscopic fundal tumors. No side-effects were reported and, most notably, none of the patients developed gallstones. This small study may help define the optimal duration, dose, and administration interval of the treatment. Slow-release somatostatin analogue is a safe and efficacious treatment for type 1 and 2 gastric carcinoid tumors, and can be used when tumors are growing rapidly. Slow-release somatostatin analogue represents an alternative to repeated endoscopic treatment or high-risk surgery.

A composite adenoendocrine carcinoma of the stomach arising from a neuroendocrine tumor

Gastric neuroendocrine tumors (carcinoids) are relatively uncommon neoplasms. Some 70 to 80% of these lesions occur in patients with autoimmune body gastritis. This disorder, however, is also a risk factor for the development of conventional gastric adenocarcinomas. We report a case of a patient with autoimmune body gastritis and a well-differentiated neuroendocrine tumor of the stomach, which was removed with endoscopic full-thickness resection in sano upon signs of invasive growth several years after its first diagnosis. Histological examination surprisingly showed a composite glandular-endocrine gastric carcinoma. We discuss the histopathological genesis of the tumor and provide evidence that endoscopic full-thickness resection might be an oncologically appropriate minimally invasive treatment for such gastric lesions.

CTGF, intestinal stellate cells and carcinoid fibrogenesis

AIM: To investigate the role of small intestinal carcinoid tumor-derived fibrotic mediators, TGFβ1 and CTGF, in the mediation of fibrosis via activation of an “intestinal” stellate cell.

METHODS: GI carcinoid tumors were collected for Q RT-PCR analysis of CTGF and TGFβ1. Markers of stellate cell desmoplasia were identified in peritoneal fibrosis by immunohistochemistry and stellate cells cultured from fresh resected fibrotic tissue. CTGF and TGFβ1 were evaluated using quantitative tissue array profiling (AQUA analysis) in a GI carcinoid tissue microarray (TMA) with immunostaining and correlated with clinical and histologically documented fibrosis. Serum CTGF was analyzed using a sandwich ELISA assay.

RESULTS: Message levels of both CTGF and TGFβ1 in SI carcinoid tumors were significantly increased (> 2-fold, P < 0.05) versus normal mucosa and gastric (non-fibrotic) carcinoids. Activated stellate cells and markers of stellate cell-mediated fibrosis (vimentin, desmin) were identified in histological fibrosis. An intestinal stellate cell was immunocytochemically and biochemically characterized and its TGFβ1 (10-7M) initiated CTGF transcription response (> 3-fold, P < 0.05) demonstrated. In SI carcinoid tumor patients with documented fibrosis, TMA analysis demonstrated higher CTGF immunostaining (AQUA Score: 92 ± 8; P <0.05), as well as elevated TGFβ1 (90.6 ± 4.4, P < 0.05). Plasma CTGF (normal 12.5 ± 2.6 ng/mL) was increased in SI carcinoid tumor patients (31 ± 10 ng/mL, P < 0.05) compared to non-fibrotic GI carcinoids (< 15 ng/mL).

CONCLUSION: SI carcinoid tumor fibrosis is a CTGF/TGFβ1-mediated stellate cell-driven fibrotic response. The delineation of the biology of fibrosis will facilitate diagnosis and enable development of agents to obviate its local and systemic complications.

A three-decade analysis of 3,911 small intestinal neuroendocrine tumors: the rapid pace of no progress

OBJECTIVES

Small intestinal neuroendocrine tumors (SI-NETs) are the most common gastrointestinal neuroendocrine tumor, but their natural history and outcome remain poorly defined, which hinders both the prediction of disease progression and appropriate therapeutic options. We examined patterns, incidence, prognosis, and outcomes of these tumors over a 30-yr period.

METHODS

Data were extracted from the NCI's SEER registry (1973-2002). Incidence rates, distribution, and 5-yr survival rates were analyzed and adjusted (U.S. decennial census data).

RESULTS

Of the 18,641 NETs, 3,911 (21.0%) were SI-NETs, of which 1,953 (49.6%) were ileal. Since 1973, both SI-NET and its ileal variant have increased annually by 3.8% and 2.1%, respectively. Ileal tumors, as a percentage of SI tumors, have increased from 52% to 63.6%. The age-adjusted incidence of ileal, small intestinal, and digestive system NETs has increased 225%, 460%, and 720% over 30 yr. Ileal tumors have specifically increased in prevalence in white (274%) and black (500%) men and women (213% and 286%, respectively); an overall increase of fourfold in blacks and 2.4-fold in whites. Although 83.3% of SI-NETs were staged, 83.7% were histologically ungraded. Five-year survival rates for SI-NETs were 62.6 +/- 1% (all stages), 73.8% (localized), 72% (regional), and 43.2% (distant). These have not significantly altered since 1973 (P= 0.11).

CONCLUSIONS

SI-NETs have increased, particularly in men and in the black population, which may be due to in vivo changes, increased clinical and pathological awareness, or increased detection of tumors. SI-NETs are malignant, diagnosed late, and survival rates have remained unchanged over 30 yr.

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.

Long-term endoscopic and clinical follow-up of untreated type 1 gastric neuroendocrine tumours

BACKGROUND AND AIMS

Type 1 gastric neuroendocrine tumour surveillance and treatment are a matter of debate. Endoscopic, or surgical, resection and chronic somatostatin analog therapy have been proposed. Based on the favourable behaviour of this neoplasm, we performed an endoscopic and clinical follow-up in 11 patients affected by type 1 gastric neuroendocrine tumours, avoiding any specific treatment.

METHODS

Between 1994 and 2006, we prospectively recorded the data of 11 untreated patients with type 1 gastric neuroendocrine tumours who underwent an endoscopic and clinical follow-up. All the patients were also evaluated by means of an abdominal computed tomography scan, somatostatin receptor scintigraphy and blood tests.

RESULTS

During the follow-up (median 54 months, range 9-136), the endoscopic picture of 4 (36%) out of 11 patients changed in terms of increased number of lesions. In none of the cases were detected any lesions that exceeded 10mm in diameter, and none of the patients demonstrated any evidence of local or distant metastases.

CONCLUSIONS

Our data confirm the literature data of the indolent behaviour of type 1 gastric neuroendocrine tumours and suggest that a careful endoscopic follow-up, without any treatment, might represent a reasonable and safe option in selected patients.

A comparison of the effects of gastrin, somatostatin and dopamine receptor ligands on rat gastric enterochromaffin-like cell secretion and proliferation

Gastrin regulates ECL cell histamine release and is a critical determinant of acid secretion. ECL cell secretion and proliferation is inhibited by gastrin antagonists and somatostatin but little is known about the role of dopamine agonists in this process. Since the ECL cell exhibits all three classes of receptor we evaluated and compared the effects of the gastrin receptor antagonist, (YF476), lanreotide (SST agonist) and novel dopaminergic agents (BIM53061 and BIM27A760) on ECL cell histamine secretion and proliferation. Highly enriched (>98%) ECL cell preparations prepared from rat gastric mucosa using a FACS approach were studied. Real-time PCR confirmed presence of the CCK2, SS2 and SS5 and D1 receptors on ECL cells. YF476 inhibited histamine secretion and proliferation with IC(50)s of 1.25 nM and 1.3 x 10(-11) M respectively, values 10-1000x more potent than L365,260. Lanreotide inhibited secretion and proliferation (2.2 nM, 1.9 x 10(-10) M) and increased YF476-inhibited proliferation a further 5-fold. The dopamine agonist, BIM53061, inhibited gastrin-mediated ECL cell secretion and proliferation (17 nM, 6 x 10(-10) M) as did the novel dopamine/somatostatin chimera BIM23A760 (22 nM, 4.9 x 10(-10) M). Our studies demonstrate that the gastrin receptor antagonist, YF476, is the most potent inhibitor of ECL cell histamine secretion and proliferation. Lanreotide, a dopamine agonist and a dopamine/somatostatin chimera inhibited ECL cell function but were 10-1000x less potent than YF476. Agents that selectively target the CCK2 receptor may provide alternative therapeutic strategies for gastrin-mediated gastrointestinal cell secretion and proliferation such as evident in the hypergastrinemic gastric carcinoids associated with low acid states.

Octreotide induces apoptosis in the oxyntic mucosa

Previous studies show that octreotide LAR causes regression of gastric ECL-cell carcinoids, reducing both number and size of tumours. This study examines the molecular mechanisms behind the antiproliferative effect of octreotide on the oxyntic mucosa. Female rats received octreotide LAR for 21 days. Serum gastrin was measured and tissue samples for RNA extraction and histology collected from the oxyntic mucosa. Affymetrix analysis showed regulated genes related to apoptosis and proliferation, and a large group of regulated growth-related transcription factors. Verification by real time qRT-PCR showed a high degree of consistency to the microarray results. Supporting the molecular results, histomorphometry showed significant decreases in the number of gastric glands, cells per gland and length of glands, and a tendency towards increased apoptosis and decreased proliferation. Thus, octreotide exerts a negative effect on oxyntic mucosal growth, and induces extensive gene expression changes relevant to growth regulation.

Prognostic value of immunohistochemistry in gastric neuroendocrine (carcinoid) tumors

Three subtypes of enterochromaffin-like cell tumors (carcinoids) have been described: type I, associated with chronic atrophic gastritis; type II, multiple endocrine neoplasia 1 and Zollinger-Ellison syndrome; and type III, sporadic tumors.

OBJECTIVES

(i) To investigate the immunoexpression of Ki-67, p53 and Bcl-2 proteins in enterochromaffin-like cell (carcinoid) tumors and (ii) to evaluate the prognostic value of these markers.

METHODS

Fifty-four samples from 21 patients with gastric carcinoid tumors were sectioned and immunostained using avidin-biotin peroxidase method.

RESULTS

The mean age was 62.2+/-11.4 years (36-83 years-old) and 13 (61.9%) were women. Type I lesions were detected in 61.9% and type III in 38.1%. Tumors were single in 10 (47.6%) and were multiple and/or multicentric in 11 (52.4%). Nuclear p53 immunoreactivity was observed in 6/21 patients (28.6%), and all of them were type III tumors (6/8), compared with no p53 expression in type I (0/13), P=0.0002. p53 expression was also associated with high degree of cell proliferation (Ki-67-positive nuclear cells), P=0.00001. Bcl-2 expression was either unreactive or weakly positive in all tumor lesions. The mean follow-up period was 50.4 months (SD=45.2), varying from 6 to 144 months. Overall survival time of patients with positive p53 expression and high proliferative rate was significantly lower than that of negative patients (14.4 vs 123 months, P=0.0007).

CONCLUSIONS

(i) p53 immunoexpression associated with high proliferative rate was useful to distinguish between type I and type III gastric carcinoid tumors and (ii) these markers were able to predict a shorter survival.

Review article: Pathogenesis and management of gastric carcinoid tumours

BACKGROUND

Gastric carcinoid tumours are rare, but are increasing in incidence.

AIM

To discuss tumour pathogenesis and outline current approaches to patient management.

METHODS

Review of published articles following a Pubmed search.

RESULTS

Although interest in gastric carcinoids has increased since it was recognized that they are associated with achlorhydria, to date there is no definite evidence that humans taking long-term acid suppressing medication are at increased risk. Type I tumours are associated with autoimmune atrophic gastritis and hypergastrinaemia, type II are associated with Zollinger-Ellison syndrome, multiple endocrine neoplasia-1 and hypergastrinaemia and sporadic type III carcinoids are gastrin-independent and carry the worst prognosis. Careful investigation of these patients is required, particularly to identify the tumour type, the source of hypergastrinaemia and the presence of metastases. Treatment can be directed at the source of hypergastrinaemia if type I or II tumours are still gastrin responsive and not growing autonomously. Type III tumours should be treated surgically.

CONCLUSIONS

Advances in our understanding of the pathogenesis of gastric carcinoids have led to recent improvements in investigation and management. Challenges remain in identifying the genetic and environmental factors, in addition to hypergastrinaemia, that are responsible for tumour development in susceptible patients.

p21 and p27 immunoexpression in gastric well differentiated endocrine tumors (ECL-cell carcinoids)

AIM: To investigate the expression of cyclin-dependent kinase inhibitors p21 and p27 in gastric well differentiated endocrine tumors (GWDET) (ECL-cell carcinoids).

METHODS: The expressions of p21 and p27 were examined immunhistochemically in endoscopic biopsy specimens from 16 patients matching the diagnostic criteria of GWDET. Percentage of positive nuclear staining either weak or strong was noted. The association of immunoexpressions with age, gender, tumor localization, multifocality and accompanying chronic atrophic gastritis, neuroendocrine cell hyperplasia (NEH), neuroendocrine dysplasia (NED), intestinal metaplasia (IM), Ki-67 proliferation index and clinical outcome were also evaluated.

RESULTS: All cases expressed p27 with a mean expression score of 43.6%, while 31.3% of the cases showed any p21 expression. p21 and p27 immunoexpressions were significantly correlated with each other (P < 0.01), and the p21-expressing group had higher p27 expression scores (68% vs 22%). p21 and p27 expressions were lower in women, in non-atrophic mucosa and cases whose tumors were located somewhere other than fundus without submucosal extension. On contrary, p21 and p27 expressions were higher in males and the patients with submucosal extension and atrophic gastritis. Cases presenting lower p27 scores had solitary tumors showing neither NEH-NED nor IM. Despite, cases with lower p21 expression presented multifocal tumors accompanied by NEH-NED. However, no correlation of p21 and p27 expressions was found with age and Ki-67 expression.

CONCLUSION: p27 is widely expressed in GWDETs, while p21 expression is sparse and observed in two thirds of the cases. Loss of p21 and p27 expressions may be correlated with different carcinoid tumor subtypes; however, more studies are needed to assess the role of these prospective markers in gastrointestinal endocrine tumors.

Cholecystokinin and gastrin receptors

Cholecystokinin and gastrin receptors (CCK1R and CCK2R) are G protein-coupled receptors that have been the subject of intensive research in the last 10 years with corresponding advances in the understanding of their functioning and physiology. In this review, we first describe general properties of the receptors, such as the different signaling pathways used to exert short- and long-term effects and the structural data that explain their binding properties, activation, and regulation. We then focus on peripheral cholecystokinin receptors by describing their tissue distribution and physiological actions. Finally, pathophysiological peripheral actions of cholecystokinin receptors and their relevance in clinical disorders are reviewed.

The role of genetic markers--NAP1L1, MAGE-D2, and MTA1--in defining small-intestinal carcinoid neoplasia

BACKGROUND

Standard clinical and immunohistochemical methods cannot reliably determine whether a small intestinal carcinoid (SIC) is indolent or aggressive. We hypothesized that carcinoid malignancy could be defined by using quantitative reverse transcriptase-polymerase chain reaction (QRT-PCR) and immunohistochemical approaches that evaluate potential marker genes.

METHODS

Candidate marker gene expression (nucleosome assembly protein 1-like 1 [NAP1L1], melanoma antigen D2 [MAGE-D2], and metastasis-associated protein 1 [MTA1]) identified by Affymetrix transcriptional profiling was examined by QRT-PCR in SIC, liver, and lymph node (LN) metastases, colorectal carcinomas, and healthy tissues. Immunohistochemical expression levels of MTA1 were analyzed quantitatively by a novel automated quantitative analysis in a tissue microarray of 102 gastrointestinal carcinoids and in a breast/prostate carcinoma array.

RESULTS

Affymetrix transcriptional profiling identified three potentially useful malignancy-marker genes (out of 1709 significantly altered genes). By QRT-PCR, NAP1L1 was significantly (P < .03) overexpressed in SIC compared with colorectal carcinomas and healthy tissue. Increased levels (P < .05) were identified in both liver and LN metastases. Levels in colorectal carcinomas were the same as in healthy mucosa. MAGE-D2 and MTA1 were increased (P < .05) in primary tumors and metastases and overexpressed in carcinomas. Automated quantitative analysis demonstrated the highest levels of MTA1 immunostaining in malignant primary SICs and in metastases to the liver and LN. These were significantly increased (P < .02) compared with nonmetastatic primary tumors. MTA1 was overexpressed in breast and prostate carcinomas (P < .05).

CONCLUSIONS

SICs overexpress the neoplasia-related genes NAP1L1 (mitotic regulation), MAGE-D2 (adhesion), and MTA1 (estrogen antagonism). The ability to determine the malignant potential of these tumors and their propensity to metastasize provides a biological rationale for the management of carcinoids and may have prognostic utility.

One-year follow-up study of patients with enterochromaffin-like cell carcinoids after treatment with octreotide long-acting release

OBJECTIVE

In a one-year study of 5 patients with chronic atrophic gastritis (CAG), pernicious anaemia (PA), hypergastrinaemia and enterochromaffin-like (ECL) cell tumours, the somatostatin analogue octreotide LAR (long-acting release) in a dose of 20 mg given intramuscularly at monthly intervals had an antiproliferative effect on the ECL cells. The aim of the present study was to follow neuroendocrine (NE) markers in the blood and macroscopic and histopathological changes in the stomach during a 12-month follow-up after discontinuation of octreotide LAR treatment.

MATERIAL AND METHODS

Five patients underwent upper gastrointestinal endoscopy at 6 and 12 months' follow-up after octreotide LAR treatment. Biopsies from flat, oxyntic mucosa and from tumours were obtained. Sections were stained with haematoxylin-erythrosin and immunostained for the NE cell marker chromogranin A (CgA). Serum gastrin and CgA were measured every 3 months.

RESULTS

The number of visible tumours was unchanged (7) at 12 months' follow-up. One lesion showed carcinoid tumour and the others various degrees of linear and micronodular NE hyperplasia. At the same time-point, biopsies from flat, oxyntic mucosa showed a slightly (non-significant) elevated number of CgA immunoreactive (IR) cells. Serum gastrin increased from 186+/-50 pM (mean+/-SEM) to 603+/-109 pM (normal < 40 pM); p<0.05, and serum CgA increased non-significantly from 25+/-2 ng/ml (normal < 30 ng/ml) to 61+/-11 ng/ml.

CONCLUSIONS

During follow-up, slightly elevated levels of serum CgA and CgA IR cells in the oxyntic mucosa, without significant recurrence of ECL cell carcinoids, were observed.

Gastric carcinoids: biologic behavior and prognosis after differentiated treatment in relation to type

OBJECTIVE

To analyze tumor biology and the outcome of differentiated treatment in relation to tumor subtype in patients with gastric carcinoid.

BACKGROUND

Gastric carcinoids may be subdivided into ECL cell carcinoids (type 1 associated with atrophic gastritis, type 2 associated with gastrinoma, type 3 without predisposing conditions) and miscellaneous types (type 4). The biologic behavior and prognosis vary considerably in relation to type.

METHODS

A total of 65 patients from 24 hospitals (51 type 1, 1 type 2, 4 type 3, and 9 type 4) were included. Management recommendations were issued for newly diagnosed cases, that is, endoscopic or surgical treatment of type 1 and 2 carcinoids (including antrectomy to abolish hypergastrinemia) and radical resection for type 3 and 4 carcinoids.

RESULTS

Infiltration beyond the submucosa occurred in 9 of 51 type 1, 4 of 4 type 3, and 7 of 9 type 4 carcinoids. Metastases occurred in 4 of 51 type 1 (3 regional lymph nodes, 1 liver), the single type 2 (regional lymph nodes), 3 of 4 type 3 (all liver), and 7 of 9 type 4 carcinoids (all liver). Of the patients with type 1 carcinoid, 3 had no specific treatment, 40 were treated with endoscopic or surgical excision (in 10 cases combined with antrectomy), 7 underwent total gastrectomy, and 1 underwent proximal gastric resection. Radical tumor removal was not possible in 2 of 4 patients with type 3 and 7 of 9 patients with type 4 carcinoid. Five- and 10-year crude survival rates were 96.1% and 73.9% for type 1 (not different from the general population), but only 33.3% and 22.2% for type 4 carcinoids.

CONCLUSION

Subtyping of gastric carcinoids is helpful in the prediction of malignant potential and long-term survival and is a guide to management. Long-term survival did not differ from that of the general population regarding type 1 carcinoids but was poor regarding type 4 carcinoids.

An analysis of rare carcinoid tumors: clarifying these clinical conundrums

Carcinoid tumors are distinct neuroendocrine neoplasms with characteristic histological, clinical, and biological properties. Though commonly associated with the gastrointestinal tract and bronchopulmonary system, a substantial number of these tumors originate in less common anatomical sites and can range from indolent, unrecognized entities to highly active, metastatic secretory tumors. Their presentation within unfamiliar locations often results in clinical confusion, and they persist as unrecognized lesions, subjecting patients to delayed, inappropriate, or ineffective treatment. The authors reviewed 13,715 carcinoid tumors identified by three consecutive registries of the National Cancer Institute (NCI) from 1950 to 1999, focusing on the anatomic sites accounting for less than one percent of all carcinoids. In addition, data from the world's literature published on carcinoid tumors within these particular anatomic locations were then analyzed with respect to incidence, clinical presentation, symptoms, diagnostic evaluation, microscopic and immunohistochemical findings, treatment strategies, and prognosis. The primary organs in which carcinoids are most commonly mistaken for some of the more conspicuous endemic tumors include the esophagus, pancreas, liver, biliary tract, gallbladder, and Meckel's diverticulum, as well as within the pelvic and otolaryngeal organs and the breast. In general, the highest proportion of "rare" carcinoids was identified in the gastrointestinal (GI) tract, with the ovary as the single most affected extra-GI site. Tumors with the worst prognosis were those that involved the pancreas (37.5%: 5-year survival) and those in the cervix (12-33%: 3-year survival). While gastrointestinal carcinoids have become a more recognized entity and thus more amenable to identification, similar lesions are often not considered in other sites and have often either been overlooked or misdiagnosed. Widespread reports of their occurrence in rare locations warrants attention. The diminution of the likelihood of inadvertently neglecting these often benign, indolent neoplasms that are well known to metastasize if unaddressed would represent an important advance. Familiarity with such unusual sites of origin will facilitate appropriate recognition and characterization of such tumors, allowing for timely intervention.

Current status of gastrointestinal carcinoids

Gastrointestinal (GI) carcinoids are ill-understood, enigmatic malignancies, which, although slow growing compared with adenocarcinomas, can behave aggressively. Carcinoids are classified based on organ site and cell of origin and occur most frequently in the GI (67%) where they are most common in small intestine (25%), appendix (12%), and rectum (14%). Local manifestations--mass, bleeding, obstruction, or perforation--reflect invasion or tumor-induced fibrosis and often result in incidental detection at emergency surgery. Symptoms are protean (flushing, sweating, diarrhea, bronchospasm), usually misdiagnosed, and reflect secretion of diverse amines and peptides. Biochemical diagnosis is established by elevation of plasma chromogranin A (CgA), serotonin, or urinary 5-hydroxyindoleacetic acid (5-HIAA), while topographic localization is by Octreoscan, computerized axial tomography (CAT) scan, or endoscopy/ultrasound. Histological identification is confirmed by CgA and synaptophysin immunohistochemistry. Primary therapy is surgical excision to avert local manifestations and decrease hormone secretion. Hepatic metastases may be amenable to cytoreduction, radiofrequency ablation, embolization alone, or with cytotoxics. Hepatic transplantation may rarely be beneficial. Chemotherapy and radiotherapy have minimal efficacy and substantially decrease quality of life. Intravenously administered receptor-targeted radiolabeled somatostatin analogs are of use in disseminated disease. Local endoscopic excision for gastric (type I and II) and rectal carcinoids may be adequate. Somatostatin analogues provide the most effective symptomatic therapy, although interferon has some utility. Overall 5-year survival for carcinoids of the appendix is 98%, gastric (types I/II) is 81%, rectum is 87%, small intestinal is 60%, colonic carcinoids is 62%, and gastric type III/IV is 33%.

Plasma chromogranin A in patients with autoimmune chronic atrophic gastritis, enterochromaffin-like cell lesions and gastric carcinoids

OBJECTIVE

In atrophic body gastritis (ABG) chronic hypergastrinaemia stimulates enterochromaffin-like (ECL) cell proliferation with development of cell hyperplasia, dysplasia and possibly type-1 gastric carcinoids. As circulating chromogranin A (CgA) levels are a marker of neuroendocrine tumours, we evaluated the clinical usefulness of CgA assay in ABG patients to detect those with carcinoids.

DESIGN AND METHODS

Plasma CgA levels were measured using a commercial ELISA in 45 healthy volunteers, nine patients with type-1 gastric carcinoids and 43 consecutive ABG patients (21 without and 22 with ECL cell hyperplasia/dysplasia).

RESULTS

CgA levels were significantly higher in ABG patients with and without gastric carcinoids than in healthy subjects (P < 0.001). The highest values occurred in patients with carcinoids (median (interquartile range): 58.1 (44.5-65.3) U/l) and with ECL cell hyperplasia/dysplasia (35.5 (31.8-48.65) U/l) but there were no significant differences in CgA among the various subgroups of ABG patients classified according to ECL cell status. Nevertheless, in ABG patients without carcinoids CgA values correlated with the presence and severity of ECL cell lesions (r(s) = 0.428, P < 0.01). The sensitivity and specificity of the CgA assay in identifying patients with carcinoids were 100 and 23% respectively.

CONCLUSIONS

CgA plasma levels reflect the histological degree of ECL cell lesions in patients with ABG but the assay specificity is too low to detect among these patients those with gastric carcinoids.

Neuroendocrine tumour management: a team approach

This article gives an overview of neuroendocrine tumours of the gut, liver and pancreas and will make the case for a multidisciplinary approach to management.

Prise en charge chirurgicale des tumeurs endocrines du tractus gastro-intestinal

Surgical management of gastro-intestinal endocrine tumors has to be adapted to tumor localization and disease extension (local and general). The aim of this literature review was to define surgical management of these unfrequent tumors.

The diagnosis and medical management of advanced neuroendocrine tumors

Neuroendocrine tumors (NETs) constitute a heterogeneous group of neoplasms that originate from endocrine glands such as the pituitary, the parathyroids, and the (neuroendocrine) adrenal, as well as endocrine islets within glandular tissue (thyroid or pancreatic) and cells dispersed between exocrine cells, such as endocrine cells of the digestive (gastroenteropancreatic) and respiratory tracts. Conventionally, NETs may present with a wide variety of functional or nonfunctional endocrine syndromes and may be familial and have other associated tumors. Assessment of specific or general tumor markers offers high sensitivity in establishing the diagnosis and can also have prognostic significance. Imaging modalities include endoscopic ultrasonography, computed tomography and magnetic resonance imaging, and particularly, scintigraphy with somatostatin analogs and metaiodobenzylguanidine. Successful treatment of disseminated NETs requires a multimodal approach; radical tumor surgery may be curative but is rarely possible. Well-differentiated and slow-growing gastroenteropancreatic tumors should be treated with somatostatin analogs or alpha-interferon, with chemotherapy being reserved for poorly differentiated and progressive tumors. Therapy with radionuclides may be used for tumors exhibiting uptake to a diagnostic scan, either after surgery to eradicate microscopic residual disease or later if conventional treatment or biotherapy fails. Maintenance of the quality of life should be a priority, particularly because patients with disseminated disease may experience prolonged survival.