Review article: current status of gastrointestinal carcinoids

Effect of metastatic site on survival in patients with neuroendocrine neoplasms (NENs). An analysis of SEER data from 2010 to 2014

BACKGROUND

Neuroendocrine neoplasms (NENs) display variable behaviors based on origin and grade. We assumed that both tumor origin and the location of metastasis may play a role in survival.

METHODS

We queried the SEER database (2010-2014) for patients with an established diagnosis of NENs and documented site of metastasis and identified 2005 patients. Overall survival (OS) at the time points were estimated by the Kaplan-Meier method Cox proportional-hazards models were used to evaluate the relationship of the interested variables and OS.

RESULTS

Lung, liver, bone and brain metastases were observed in 9, 77, 7 and 6% of metastatic patients respectively. In the multivariate model, metastasis locations were significantly associated with worse survival (liver HR: 1.677 (1.226-2.294); (bone metastasis HR: 1.412 (0.965-2.065); brain HR: 1.666 (1.177-2.357)). We produced a scoring system based on site of origin, metastasis location, age, gender, histology and tumor size that can stratify metastatic NEN patients in low, intermediate and high-risk categories to help physicians with decision making.

CONCLUSION

Site of metastasis plays an important role in survival of metastatic NEN patients independent of commonly described prognostic factors and should be considered in survival estimates.

Accuracy of Grading in Pancreatic Neuroendocrine Neoplasms and Effect on Survival Estimates: An Institutional Experience

BACKGROUND

Accurate grading of neuroendocrine neoplasms (NENs) is crucial for proper assessment of prognosis. Estimation of the proliferative indices, if not performed properly, is largely erroneous due to significant intratumoral heterogeneity. We sought to establish the degree of error in the grading of a cohort of curatively resected pancreatic NENs (PanNENs) and the theoretical impact of that in a larger cohort of Surveillance, Epidemiology, and End Results (SEER) patients.

METHODS

A retrospective query of an institutional surgical database was performed from 2000 to 2018 to identify optimally resected PanNENs, which were reviewed by two gastrointestinal pathologists and regraded according to the WHO 2017 classification. Overall survival and recurrence-free survival were estimated using the Kaplan-Meier method for original and new grading systems, respectively and Cox proportional hazards models were used to evaluate the effect of the interested variables, including new grading systems.

RESULTS

A total of 176 cases were identified. After regrading, 17/64 (26.6%) G1 neoplasms were classified as G2 and 12/95 (12.6%) G2 neoplasms were classified as G1, while 1/11 (9.1%) G3 neoplasms were classified as G2. Our expert gastrointestinal pathologists agreed on 97% of reclassified cases by blind review. Application of the G1/G2 misclassification errors on various groups, including PanNENs, in a SEER database of 1385 patients rendered the reported survival differences nonsignificant (1000 repetitions; p = 0.063, 95% confidence interval 0.056-0.070).

CONCLUSIONS

Mischaracterization of grade is common in optimally resected PanNENs but is eliminated with proper training and adherence to guidelines. The discrepancy rates can cast doubt on the generally accepted survival differences between G1 and G2 patients, as surmised by large database analyses.

Resectability of Rectal Neuroendocrine Tumors Using Endoscopic Mucosal Resection with a Ligation Band Device and Endoscopic Submucosal Dissection

Background

Rectal neuroendocrine tumors (NETs) < 10 mm in diameter, limited to the submucosa without local or distant metastasis, can be treated endoscopically. Endoscopic mucosal resection with a ligation band device (EMR-L) and endoscopic submucosal dissection (ESD) have been employed to resect rectal NETs. We evaluated and compared the clinical outcomes of EMR-L and ESD for endoscopic resection of rectal NETs G1 < 10 mm in diameter.

Methods

We conducted a retrospective study of 82 rectal NETs in 82 patients who underwent either EMR-L or ESD. Therapeutic outcomes (en bloc resection and complete resection rates), procedure time, and procedure-related adverse events were evaluated. Additionally, we measured the distance of the lateral and vertical margins from the border of the tumor in pathologic specimens and compared the resectability between EMR-L and ESD.

Results

Sixty-six lesions were treated using EMR-L and 16 using ESD. En bloc resection was achieved in all patients. The complete resection rate with EMR-L was significantly higher than that with ESD (95.5% vs.75.0%, p = 0.025). The prevalence of vertical margin involvement was significantly higher in the ESD group than in the EMR-L group (12.5% vs. 0%, p = 0.036), and ESD was more time consuming than EMR-L (24.21 ± 12.18 vs. 7.05 ± 4.53 min, p < 0.001). The lateral and vertical margins were more distant in the EMR-L group than in the ESD group (lateral margin distance, 1661 ± 849 vs. 1514 ± 948 μm; vertical margin distance, 277 ± 308 vs. 202 ± 171 μm).

Conclusions

EMR-L is more favorable for small rectal NETs with respect to therapeutic outcomes, procedure time, and technical difficulties. Additionally, EMR-L enables achievement of sufficient vertical margin distances.

Metachronous and Synchronous Cancers in Patients with Neuroendocrine Tumors

INTRODUCTION

Neuroendocrine tumors (NETs) are a heterogeneous group of malignancies with various clinical presentations and growth rates. NET incidence has been estimated to 2.5-5 per 100,000 people per year, and NET prevalence is 35 per 100,000. They are frequently associated with synchronous or metachronous second primary malignancies (SPM).

METHODS

We retrospectively reviewed our institutional database on NET patients. We report on 30 patients with NETs and SPMs from a series of 262 patients with NETs: 10 patients with synchronous NETs (33.3%) and 20 with metachronous SPMs (66.6%).

RESULTS

The median patient age was 67 years. Of the 10 synchronous lesions, 50% were observed in the GI tract. The most common locations of these lesions were the colon (15%) and pancreas (25%). In 2 patients, there was an association of prostate neoplasia with a subsequent NET of the pancreas.

CONCLUSIONS

Only few studies have examined the association between NETs and SPMs. Our study showed that the risk of second cancer following NETs is increased. In this single-institution retrospective review, our incidence of additional malignancies in patients with NET was 11.4%.

Nutritional and vitamin status in patients with neuroendocrine neoplasms

Symptoms of gastroenteropancreatic located neuroendocrine neoplasms (GEP-NENs) are often related to food intake and manifest as abdominal pain or diarrhoea which can influence patients nutritional status. Malnutrition is common in cancer patients and influences quality of life, treatment options and survival but is also present in up to 40% of patients with GEP-NENs. As part of malnutrition there are often deficiencies in fat-soluble vitamins, mainly vitamin D. Little knowledge exists on trace elements. Several factors influence the development of malnutrition such as size and localisation of the primary tumour as well as metastases, side effects from treatment but also hormone production of the tumour itself. One of the main influencing factors leading to malnutrition is diarrhoea which leads to dehydration and electrolyte disturbances. Treatment of diarrhoea should be guided by its cause. Screening for malnutrition should be part of routine care in every GEP-NEN patient. Multidisciplinary treatment including dietician support is necessary for all malnourished patients with GEP-NENs.

Gastrointestinal Carcinoids and Colorectal Cancers: Is It a Paracrine Effect?

Background

Carcinoid tumors are uncommon neuroendocrine tumors that account for less than 1% of gastrointestinal tract malignancies. They have a reported incidence of 1.3 per 100,000. Small bowel carcinoids are the commonest and have the highest incidence of associated second primary malignancies, followed by appendiceal and colorectal carcinoids. The most common second primary malignancy is colorectal adenocarcinoma.

Case series

We report a series of 11 patients observed in the period 2006–2011 with primary gastrointestinal tract cancers and synchronous carcinoids discovered incidentally by the histopathologist in the resected primary cancer specimen.

Results

In all patients with synchronous carcinoids and colorectal adenocarcinoma there was a pattern of similar embryonic visceral origin. Is this a paracrine effect from biological peptides produced by the carcinoids?

Clinical profile and treatment outcomes of advanced neuroendocrine tumours in rural and regional patients: a retrospective study from a regional cancer centre in North Queensland, Australia

BACKGROUND

Neuroendocrine tumours (NET) arise from neuroendocrine cells, which are widely distributed throughout the body. However, diagnosing NET is difficult due to nonspecific symptoms and the paucity of experience among health professionals. This retrospective study was carried out to improve our understanding about NET. This knowledge can be used for optimal utilisation and distribution of limited resources.

AIM

To study the clinical profile, treatment and survival outcomes for advanced NET patients in Australian regional and remote settings.

METHODS

We reviewed all adult patients who were diagnosed with NET between 1994 and 2012. Patients' data were extracted from electronic databases of The Townsville Cancer Centre. Remoteness was based on postcodes, with patients stratified as regional or rural North Queensland according to Australian Standard Geographical Classification (ASGC). Overall survival was studied using survival analysis.

RESULTS

Data from 79 patients were included in the study. The median age at diagnosis was 60 years. A total of 48 patients (60.8%) was male and 31 (39.2%) female. The majority of the patients lived in rural areas (51, 64%) as compared to residing in regional areas (28, 36%). There were 34 deaths at the study cut-off point. Median overall survival of NET patients in rural areas is significantly less than those living in regional areas (1613 days vs. 2935 days, respectively), P = 0.03.

CONCLUSION

Remoteness has an adverse impact on overall survival of NET patients. This outcome may be because of varied access to health services and/or lack of access to specialised scans and medical and surgical expertise.

Mechanics of Fluid-Filled Interstitial Gaps. I. Modeling Gaps in a Compact Tissue

Fluid-filled interstitial gaps are a common feature of compact tissues held together by cell-cell adhesion. Although such gaps can in principle be the result of weak, incomplete cell attachment, adhesion is usually too strong for this to occur. Using a mechanical model of tissue cohesion, we show that, instead, a combination of local prevention of cell adhesion at three-cell junctions by fluidlike extracellular material and a reduction of cortical tension at the gap surface are sufficient to generate stable gaps. The size and shape of these interstitial gaps depends on the mechanical tensions between cells and at gap surfaces, and on the difference between intracellular and interstitial pressures that is related to the volume of the interstitial fluid. As a consequence of the dependence on tension/tension ratios, the presence of gaps does not depend on the absolute strength of cell adhesion, and similar gaps are predicted to occur in tissues of widely differing cohesion. Tissue mechanical parameters can also vary within and between cells of a given tissue, generating asymmetrical gaps. Within limits, these can be approximated by symmetrical gaps.

Mixed adenoneuroendocrine carcinoma derived from the cystic duct: A case report

INTRODUCTION

Mixed adenoneuroendocrine carcinomas (MANECs) derived from cystic duct are extremely rare.

PRESENTATION OF CASE

An 80-year-old woman was admitted to the department of surgery, Onomichi general hospital with abnormal liver function and jaundice. Enhanced abdominal computed tomography (CT) detected a well-enhanced papillary tumor in the cystic duct, which protruded into the common bile duct. The intrahepatic bile duct was dilated due to tumor obstruction. The entire tumor showed high intensity in T2-weighted magnetic resonance imaging (MRI) imaging. Endoscopic retrograde cholangiopancreatography (ERCP) showed that the tumor ranged from part of communication of three ducts (cystic, common hepatic and common bile duct), to the middle of common bile duct. Biliary cytology determined a class V malignancy (adenocarcinoma). Endoscopic ultrasound determined that the tumor was primarily at the cystic duct with heterogeneous echoic pattern, which extended into the common bile duct. The preoperative diagnosis was cystic duct carcinoma (T3N0M0, StageIIIA). An extended cholecystectomy with regional lymph nodes dissection was performed. Histologically, the tumor had components of both well-differentiated tubular adenocarcinoma and neuroendocrine carcinoma, which is classified as MANECs according to the 2010 WHO classification of endocrine tumors. Eight months after surgery, multiple liver metastases were discovered, and treatment with adjuvant chemotherapy was initiated.

DISSCUSION

We present a rare case of MANECs derived from cystic duct. Until now, an established adjuvant systemic chemotherapy has not emerged, and curative resection, with poor long-term prognosis, remains the only treatment option.

CONCLUSION

Though standards of treatment for MANECs have not been established,multidisciplinary theraphy is necessary to improve outcome.

Poorly Differentiated Rectal Carcinoid in a Cow

A carcinoid tumor was found as a solitary soft mass in the wall of the rectum adjacent to the anorectal junction in an adult Holstein cow. Microscopically, the tumor involved the submucosa and partly invaded the muscular layer. It consisted of a compact arrangement of a great number of large polygonal cells and a small number of small dark cells, some of which showed argyrophilia (Grimelius positive). Immunohistochemically, both types of tumor cells were positive for vimentin, keratin, and S-100 protein and weakly positive for neuron-specific enolase (NSE), whereas they were negative for some endocrine markers such as chromogranin A, insulin, glucagon, somatostatin, serotonin, adrenocorticotropic hormone, and calcitonin. Electron microscopy revealed membrane-bound secretory granules in the cytoplasm of some small dark cells. In such a poorly differentiated carcinoid, the morphologic characteristics of the small dark cells were strong evidence for the diagnosis. This is the first description of a poorly differentiated carcinoid developing in the rectum of a cow.

Usefulness of endoscopic resection using the band ligation method for rectal neuroendocrine tumors

Background/Aims

Rectal neuroendocrine tumors (NETs) are among the most common of gastrointestinal NETs. Due to recent advances in endoscopy, various methods of complete endoscopic resection have been introduced for small (≤10 mm) rectal NETs. However, there is a debate about the optimal treatment for rectal NETs. In our study, we aimed to evaluate the efficacy and feasibility of endoscopic resection using pneumoband and elastic band (ER-BL) for rectal NETs smaller than 10 mm in diameter.

Methods

A total of 55 patients who were diagnosed with rectal NET from January 2004 to December 2011 at Gil Medical Center were analyzed retrospectively. Sixteen patients underwent ER-BL. For comparison, 39 patients underwent conventional endoscopic mucosal resection (EMR).

Results

There was a markedly lower deep margin positive rate for ER-BL than for conventional EMR (6% [1/16] vs. 46% [18/39], P=0.029). Four patients who underwent conventional EMR experienced perforation or bleeding. However, they recovered within a few days. On the other hand, patients whounderwent endoscopic resection using a pneumoband did not experience any complications. In multivariate analysis, ER-BL (P=0.021) was independently associated with complete resection.

Conclusions

ER-BL is an effective endoscopic treatment with regards to deep margin resection for rectal NET smaller than 10 mm.

Endoscopic mucosal resection for rectal carcinoids under micro-probe ultrasound guidance

AIM: To assess the therapeutic value of endoscopic mucosal resection (EMR) under micro-probe ultrasound guidance for rectal carcinoids less than 1 cm in diameter.

METHODS: Twenty-one patients pathologically diagnosed with rectal carcinoids following colonoscopy in our hospital from January 2007 to November 2012 were included in this study. The patients consisted of 14 men and 7 women, with a mean age of 52.3 ± 12.2 years (range: 36-72 years). The patients with submucosal tumors less than 1 cm in diameter arising from the rectal and muscularis mucosa detected by micro-probe ultrasound were treated with EMR and followed up with conventional endoscopy and micro-probe ultrasound.

RESULTS: All of the 21 tumors were confirmed by micro-probe ultrasound as uniform hypoechoic masses originating from the rectal and muscularis mucosa, without invasion of muscularis propria and vessels, and less than 1 cm in diameter. EMR was successfully completed without bleeding, perforation or other complications. The resected specimens were immunohistochemically confirmed to be carcinoids. Patients were followed up for one to two years, and no tumor recurrence was reported.

CONCLUSION: EMR is a safe and effective treatment for rectal carcinoids less than 1 cm in diameter.

Synergistic effect of pasireotide and teriflunomide in carcinoids in vitro

BACKGROUND/AIM

Somatostatin (SST) analogs are mainstay for controlling tumor proliferation and hormone secretion in carcinoid patients. Recent data suggest that extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation may potentiate the anti-tumor effects of SST analogs in carcinoids. Additionally, ERK1/2 phosphorylating agents have been shown to suppress biomarker expression in carcinoids. Thus, Raf-1/MEK/ERK1/2 pathway activating drugs may be synergistic with SST analogs such as pasireotide (SOM230), which may be more effective than others in its class given its elevated receptor affinity and broader binding spectrum. Here, we investigate the effects of SOM230 in combination with teriflunomide (TFN), a Raf-1 activator, in a human carcinoid cell line.

METHODS

Human pancreatic carcinoid cells (BON) were incubated in TFN, SOM230 or a combination. Cell proliferation was measured using a rapid colorimetric assay. Western analysis was performed to analyze expression levels of achaete-scute complex-like 1 (ASCL1), chromogranin A (CgA), phosphorylated and total ERK1/2, and markers for apoptosis.

RESULTS

Combination treatment with SOM230 and TFN reduced cell growth beyond the additive effect of either drug alone. Combination indices (CI) fell below 1, thus quantifiably verifying synergy between both drugs as per the Chou-Talalay CI scale. Combined treatment also reduced ASCL1 and CgA expression beyond the additive effect of either drug alone. Furthermore, it increased levels of phosphorylated ERK1/2, cleaved poly(ADP)-ribose polymerase and caspase-3, and reduced levels of anti-apoptotic biomarkers. Elevated phosphorylated ERK1/2 expression following combination therapy may underlie the synergistic interaction between the two drugs.

CONCLUSION

Since efficacy is achieved at lower doses, combination therapy may palliate symptoms at low toxicity levels. Because each drug has already been evaluated in clinical trials, combinatorial drug trials are warranted.

Primary neuroendocrine tumor of the left hepatic duct: a case report with review of the literature

Primary Biliary Tract Neuroendocrine tumors (NET) are extremely rare tumors with only 77 cases been reported in the literature till now. We describe a case of a left hepatic duct NET and review the literature for this rare malignancy. To the best of our knowledge the present case is the first reported case of a left hepatic duct NET in the literature. In spite of availability of advanced diagnostic tools like Computerized Tomography (CT) Scan and Endoscopic Retrograde Cholangio Pancreaticography (ERCP) a definitive diagnosis of these tumors is possible only after an accurate histopathologic diagnosis of operative specimens with immunohistochemistry and electron microscopy. Though surgical excision remains the gold standard treatment for such tumors, patients with unresectable tumors have good survival with newer biologic agents like Octreotride.

A case of metachronous double primary neuroendocrine cancer in pancreas/ileum and uterine cervix

We describe an unusual case of a 50-year-old female patient developing two primary cancers with neuroendocrine features. Initially the patient underwent surgery for an entero-pancreatic neuroendocrine carcinoma. During the subsequent follow-up she experienced some episodes of vaginal bleeding with negative PET scanning with the tracer fluorine-18 (F-18) fluorodeoxyglucose (FDG). A Papanicolaou (pap) smear and an endometrial biopsy revealed a primary neuroendocrine cancer of the uterine cervix. The present case underlines the importance of clinical follow-up after a diagnosis of intestinal neuroendocrine tumor, investigating any new symptom. Female patients, after the diagnosis of entero-pancreatic neuroendocrine carcinoma, must be recommended to continue screening pap test examinations for the likelihood of classical squamous and glandular cervical cancers and also for neuroendocrine cervical cancer.

[Hyperplastic polyp with neoplastic transformation in a patient with atrophic gastritis and multiple gastric neuroendocrine tumors]

Hyperplastic gastric polyps are often found at GI endoscopy and are not considered premalignant lesions, although some cases of malignancy have been reported. Neuroendocrine tumors, conversely, are rare and account for approximately 1% to 2% of gastric polyps. Both hyperplastic gastric polyps and neuroendocrine tumors are related to gastric atrophy. The case of a hyperplastic polyp with multifocal areas of adenocarcinoma within the polyp associated to multiple gastric neuroendocrine tumors is reported.

[Poorly differentiated neuroendocrine carcinoma of the colon with liver metastases]

Neuroendocrine tumors of the gastrointestinal tract are highly infrequent. We report the case of a 57-year-old woman who presented with toxic syndrome, vomiting and a 3-month history diarrhea, with a final diagnosis of poorly-differentiated neuroendocrine tumor. Based on this case, we review the clinical characteristics, diagnostic procedures, prognostic factors and therapeutic possibilities in this type of tumor. Neuroendocrine tumors should be considered in the diagnosis of colonic tumors with hyperechoic liver metastases.

Cancers of the appendix: review of the literatures

Cancers of the appendix are rare. Most of them are found accidentally on appendectomies performed for appendicitis. When reviewed, majority of the tumors were carcinoid, adenoma, and lymphoma. Adenocarcinomas of appendix are only 0.08% of all cancers and the treatment remains controversial. Here we are reporting a 46-year-old male presented with symptoms of appendicitis, diagnosed with adenocarcinoma of the appendix. The patient was treated with appendectomy and refused further surgical intervention to complete hemicolectomy. Up to date, he remains asymptomatic. We performed literature review of the tumors of the appendix. Most of the benign conditions are treated with surgery alone. Lymphomas require CHOP-like chemotherapy and carcinoid syndrome treatment with somatostatin analogues. It is generally recommended that right hemicolectomy is the preferred treatment for adenocarcinoma of appendix. The role of chemotherapy is unclear due to lacking randomized trials but seems to be accepted if there is lymph node involvement or peritoneal seeding.

Carcinoid tumors of the duodenum and the ampulla of Vater: current diagnostic and therapeutic approach in a series of 8 patients. Case series

AIM

To describe the specific characteristics of duodenal/perivaterian carcinoids and to analyze the diagnostic/therapeutic approach.

MATERIAL AND METHODS

Eight patients were included in our study. Symptoms on admission included dyspepsia, upper gastrointestinal (GI) bleeding and anemia. All patients underwent upper GI endoscopy and gastrointestinal peptides (gastrin) and neuroendocrine markers (Chromogranin-A, CgA) measurement. Imaging studies were performed in all patients, including OCTREOSCAN, while in patients with ACs MRCP or ERCP was also performed, when necessary. Definite diagnosis was confirmed by histopathologic examination.

RESULTS

Polypoid masses (carcinoids) were revealed at duodenal bulb and ampulla of Vater, in 5 and 3 patients, respectively. Serum gastrin was moderately increased in 4 patients, while in one patient it was more than 1000 pg/ml. Serum CgA was moderately increased in one patient, in whom OCTREOSCAN detected a solitary hepatic metastasis. Two patients with DC, of less than 1 cm of diameter, were treated by endoscopic polypectomy, while all the other patients underwent surgery. The patient with hepatic metastasis and positive OCTREOSCAN received also Octreotide LAR, resulting in stabilization of disease. No recurrence or metastases were observed during follow-up (range : 1.5-9.6 years).

CONCLUSIONS

In DC tumors <1 cm endoscopic excision with close follow-up is an adequate treatment, while in tumors >1 cm and in AC, surgical resection is the treatment of choice. In metastatic tumors, resection of the primary lesion with administration of somatostatin analogues may stabilize the disease and improve patient's quality of life.

Pathology of Gastrointestinal Neuroendocrine Tumors: An Update

Gastrointestinal (GI) neuroendocrine tumors (NETs) are a heterogeneous group of relatively slow-growing neoplasms with marked site-specific differences in hormonal secretion and clinical behavior. Most are sporadic neoplasms, with only 5% to 10% arising in patients with hereditary disorders, most commonly in multiple endocrine neoplasia type 1. Although a uniform terminology is not universally accepted, use of the 4-category WHO classification of these tumors is becoming more widespread, and recommendations for tumor grading and staging have been recently formulated. Most GI NETs are easily recognized on routine histologic examination; rarely, a limited panel of immunohistochemical markers may be useful in establishing the diagnosis. This article describes general and site-specific features of these tumors and outlines potential pitfalls in diagnosis.

Epidemiology of neuroendocrine cancers in an Australian population

OBJECTIVE

The aim was to explore incidence, mortality and case survivals for invasive neuroendocrine cancers in an Australian population and consider cancer control implications.

METHODS

Directly age-standardised incidence and mortality rates were investigated from 1980 to 2006, plus disease-specific survivals.

RESULTS

Annual incidence per 100,000 increased from 1.7 in 1980-1989 to 3.3 in 2000-2006. A corresponding mortality increase was not observed, although numbers of deaths were low, reducing statistical power. Increases in incidence affected both sexes and were more evident for female lung, large bowel (excluding appendix), and unknown primary site. Common sites were lung (25.9%), large bowel (23.3%) (40.9% were appendix), small intestine (20.6%), unknown primary (15.0%), pancreas (6.5%), and stomach (3.7%). Site distribution did not vary by sex (p = 0.260). Younger ages at diagnosis applied for lung (p = 0.002) and appendix (p < 0.001) and older ages for small intestine (p < 0.001) and unknown primary site (p < 0.001). Five-year survival was 68.5% for all sites combined, with secular increases (p < 0.001). After adjusting for age and diagnostic period, survivals were higher for appendix and lower for unknown primary site, pancreas, and colon (excluding appendix).

CONCLUSIONS

Incidence rates are increasing. Research is needed into possible aetiological factors for lung and large-bowel sites, including tobacco smoking, and excess body weight and lack of exercise, respectively; and Crohn's disease as a possible precursor condition.

Colonic carcinoid tumors: a clinicopathologic study of 23 patients from a single institution

CONTEXT: Colonic carcinoids, excluding those arising in the appendix, have proved to be extremely rare. Due to their rarity, the characteristics and behavior of this unusual malignancy remain unclear. OBJECTIVE: To review the clinicopathologic features of patients operated on carcinoid tumors of the colon. METHODS: Twenty-three patients (12 males and 11 females) were operated on colonic carcinoids. The mean age of the patients was 63.0 ± 12.9 years (42 to 85 years). The clinical and histopathological data of patients who were pathologically diagnosed as having carcinoid tumors and submitted to surgical treatment over a 30-year period (1977-2007) were gathered. Actuarial patient survival was estimated using the Kaplan-Meier method, with carcinoid-specific death as the outcome. RESULTS: The mean time elapsed between onset of symptoms and surgical treatment was 8.3 months (1.5 to 20 months). The most frequent symptoms or signs encountered were abdominal pain followed by anorexia or weight loss, diarrhea, abdominal tenderness, palpable abdominal mass, and rectal bleeding. No carcinoid syndrome was noted. The lesion was located in the cecum in 16 (69.6%) patients, in the sigmoid in 3 patients (13.0%), in the ascending colon in 3 patients (13.0%), and in the transverse colon in one patient (4.3%). Twenty-one (91.3%) patients were operated on curative intent. Spreading of the disease to the liver and peritoneum was found in two (8.7%) patients who submitted to intestinal bypass. The mean size of the largest mass was 3.7 ± 1.2 cm (1.5 to 6.2 cm). There were multiple (two or more) lesions in three cases (13.0%). In the resected cases, the lymph nodes were compromised in 10 patients (47.6%) and disease-free in 11 (52.4%). Venous invasion and neural infiltration were both present in five (23.8%) patients. The tumors had penetrated the muscularis propria in all resected cases. Four (17.4%) patients had a second non-carcinoid primary tumor. Three (13.0%) patients died due to postoperative complications and five (21.7%) patients died from metachronous metastases or local recurrence. Fifteen patients (65.2%) remain alive without evidence of active disease. The mean follow-up period was 12 years (1.2 to 18 years), whereas the mean global survival was 50.7 ± 34.2 months and the crude survival rate at 5 years was 62.7%. CONCLUSIONS: Carcinoid tumors of the colon are frequently right-sided and may be clinically occult until an advanced stage is reached. Based on the relatively poor survival rates reported, it is recommended that, in addition to standard surgical resection, vigorous surveillance for metastatic disease must be performed, particularly during the first 2 years after surgery. In addition, these patients require evaluation of the entire gastrointestinal tract for evidence of coexisting malignancy, along with an extended period of follow-up, because tumor recurrences after 5 years are not uncommon.

Are we missing diagnostic opportunities in cases of carcinoid tumours of the appendix?

OBJECTIVE

Carcinoid tumour of appendix is an uncommon condition that can potentially give rise to a variation in management. We aimed to assess the occurrence and mode of presentation of carcinoid tumour of appendix, and any variation of its management.

METHODS

All appendicectomies that took place at North Middlesex University Hospital, London between 1995 and 2005 were considered for study.

RESULTS

A total of 1941 appendicectomies took place. Sixteen (0.82%) patients had carcinoid tumours. The mean age of patients with carcinoid tumour (41.8 years) was significantly higher than those with non-carcinoid pathology (27.7 years) (p = 0.001). The incidence of female patients was higher than the male amongst the carcinoid tumour group (female/male ratio 2.2). None of the carcinoid tumours were identified at operation. Eight patients as well as their general practitioners (53.3%) were unaware of the diagnosis. Multidisciplinary team involvement or specialty referral took place in three cases (20%). One patient (6.6%) required right hemicolectomy. Three patients (20%) were followed-up in inconsistent manner.

CONCLUSIONS

Carcinoid tumour of the appendix remains an incidental diagnosis. Patients with carcinoids were significantly older than non-carcinoid conditions. There was a trend of increased occurrence of carcinoids amongst the females. Re-operation rate was low. There was a wide variation in involving the multidisciplinary team, conveying the diagnosis to patients as well as their general practitioners, and follow-ups. This can be perceived as a missed opportunity of selective screening of synchronous and metachronous lesions, raises clinical governance issues and has medicolegal implications.

[Gastrointestinal carcinoid tumors: cellular biology, molecular expression and physiopathological consequences of an enigmatic neoplasia]

Gastrointestinal carcinoid tumors arise from cells of the diffuse neuroendocrine system localized in the digestive trace and represent more than 70% of all carcinoid tumors in humans. The present article reviews the following topics: 1) The biological profile of these tumors (histopathology, cytokine markers, metabolic alterations, storage of neuroamines and hormonal proteins, cytodynamic behavior, and biological behavior according to embryological origin). 2) The etiological circumstances (exceptional hereditary factors, association of gastric carcinoid tumors with autoimmune gastritis, little-known exogenous factors). 3) Pathogenic aspects (persistent mitogenesis of endocrine cells associated with hypergastrinemia, inactivation of some putative tumor suppressor genes, the doubtful participation of oncogenes, autocrine action of some cellular growth-stimulating proteins). 4) The repercussions of certain physiopathological events (peritumoral desmoplastic reaction causing the "mass effect" on the digestive tube, the "kidnapping" of dietary tryptophan by tumoral cells toward an abnormal metabolic pathway; the easy metastatic dissemination coexisting with low tumoral aggressivity, and the release into the bloodstream of stored secretory products leading to "carcinoid syndrome" and some endocrine hyperfunction syndromes. Finally, it should be remembered that gastrointestinal carcinoid tumors represent only a proportion of the neoplasms classified as neuroendocrine tumors.

An evaluation of cyclooxygenase-2 as a prognostic biomarker in mid-gut carcinoid tumours

BACKGROUND/AIMS

Mid-gut carcinoids (MGC) are the most common of the gastrointestinal carcinoid tumours. There is a lack of reliable prognostic indicators for MGC. Cox-2 and Bcl-2 were evaluated as prognostic biomarkers in a cohort of well-characterised non-appendiceal MGC.

METHODS

Tissue from the primary MGC tumours of 37 patients was subjected to immunohistochemical detection of Cox-2 and Bcl-2. In 9 cases, tissue from secondary lesions was also examined. The study assessed whether tumour-associated Cox-2 and Bcl-2 expression were related to patient survival.

RESULTS

Cox-2 expression was demonstrated in 30/36 primary tumours. When all tumours were analysed, Cox regression analysis indicated a trend towards worsening survival with increasing Cox-2 histoscore (intensity x proportion; hazard ratio 1.53, 95% CI 0.93, 2.52; p = 0.09). Analysis of Cox-2-positive tumours revealed a highly significant association between increasing histoscore and decreased survival (hazard ratio 3.03, 95% CI 1.33, 6.91; p = 0.008). Tumour-associated Bcl-2 expression had no effect on patient survival (hazard ratio 1.12, 95% CI 0.42, 2.99; p = 0.82). There was no significant association between Cox-2 and Bcl-2 expression (chi(2) p = 0.16), or Cox-2 histoscore and Bcl-2 expression (MWU p = 0.59). Analysis of the Cox-2 histoscores of primary tumours and their corresponding secondary lesions revealed a statistically significant trend towards increasing histoscore in the latter (Wilcoxon p = 0.04).

CONCLUSIONS

This study has provided evidence that Cox-2 expression in primary MGC may be associated with a more negative prognostic outlook.

Gl-NETs-uniform but also diverse

In the 100 years since the term Karzinoid was first coined by Siegfried Oberndorfer to describe gastrointestinal tumors that resembled carcinomas but pursued a relatively indolent course, these tumors have captured the attention, not only of internists, surgeons, endocrinologists, and pathologists but of biochemists, physiologists, geneticists, and molecular biologists as well. Initially thought to be limited to the gut, these tumors were soon found to arise in a variety of other organs as well. With the gradual evolution of the concept of a dispersed neuroendocrine cell system and the recognition that it was made up of a galaxy of at least 20 or so functionally distinct cell types (each of which could potentially give rise to a specific type of tumor, each of which could in turn be endocrinologically functional or silent), came the realization that carcinoids should perhaps be considered as a family of neoplasms that, despite sharing certain commonalities, can however, show significant heterogeneity among themselves in some of their other features. While it may seem that our knowledge of this fascinating group of tumors has improved significantly, a closer look reveals that we may have just begun to scratch the surface.

Expression of cyclo-oxygenase-2 in gastrointestinal carcinoid tumors

BACKGROUND

Cyclo-oxygenase (COX)-2 overexpression is observed in various neoplasms and COX-2 inhibition has been attempted as prevention and/or therapy in these neoplasms. Carcinoid tumors are thought to arise from neuroendocrine cells and originate mainly in the gastrointestinal tract. Cyclo-oxygenase-2 is reportedly expressed in neuroendocrine cells of normal colorectal mucosa. The role of COX in carcinoids has not previously been investigated. The aim of the present paper was to clarify the expression of COX-1 and -2, and their role in human gastrointestinal carcinoids.

METHODS

Expression of COX-1 and -2 was studied immunohistochemically in 38 gastrointestinal carcinoids. Five bronchopulmonary and seven metastatic carcinoids were also examined, for comparison with gastrointestinal carcinoids. The immunohistochemical score (IHS) was calculated from staining intensity and immunoreactive cell population, and ranked according to four grades (negative to strong).

RESULTS

Cyclo-oxygenase-2 was expressed in all gastrointestinal carcinoids (weak, 1; moderate, 13; strong, 24) and bronchopulmonary carcinoids (weak, 1; moderate, 4), as well as their metastases (moderate, 3; strong, 4). The IHS of COX-2 in larger tumors was significantly lower than that in smaller tumors. However, the IHS of COX-2 at the advancing tumor edge was significantly higher than that at the centers of tumors >or=10 mm in size. Faint COX-1 expression was detected in only one duodenal, one rectal and four bronchopulmonary carcinoids.

CONCLUSIONS

Enhanced COX-2 expression was observed in gastrointestinal as well as bronchopulmonary carcinoids and their metastases, especially at the advancing edges of the tumors. Cyclo-oxygenase-2 may play a role in carcinoid progression.

Abnormalities of serotonin metabolism and their relation to symptoms in untreated celiac disease

BACKGROUND AND AIMS

Serotonin (5-hydroxytryptamine [5-HT]) is a key modulator of gut function that in excess causes nausea, vomiting, and diarrhea. We recently showed that patients with post-infective irritable bowel syndrome have increased postprandial release of 5-HT associated with low-grade T-cell mediated inflammation. Celiac disease is another common disease in which a T-cell enteropathy is associated with increased mucosal 5-HT levels. Our aim was to determine how this inflammatory lesion influenced 5-HT bioavailability and how changes in 5-HT related to the symptoms of nausea, vomiting, and diarrhea seen in untreated celiac patients.

METHODS

Fasting plasma and platelet 5-HT and postprandial plasma 5-HT levels were measured after a high-carbohydrate meal in celiac patients (n = 18) and healthy controls (n = 18) using high-pressure liquid chromatography. Dyspepsia was assessed during the postprandial period using a questionnaire. Finally, we compared the histology and mucosal 5-HT levels in duodenal biopsy specimens from celiac patients and controls.

RESULTS

Celiac patients had increased 5-HT-containing enterochromaffin cell numbers and significantly higher peak plasma 5-HT levels (P = .0002), postprandial area under the curve (P = .0006), and platelet 5-HT stores (P = .031) than controls. Peak 5-HT levels correlated significantly with postprandial dyspepsia scores (P = .005). Celiac patients had higher duodenal 5-HT levels (P = .007) than controls.

CONCLUSIONS

Celiac disease is associated with increased mucosal 5-HT content and enhanced 5-HT release from the upper small bowel, which correlates with postprandial dyspepsia. Serotonin excess may mediate dyspeptic symptoms in untreated celiac disease.

Therapeutic options for gastrointestinal carcinoids

Although wide surgical resection is the optimal curative therapy for carcinoid tumors, in most patients the presence of metastatic disease at diagnosis usually renders excision a palliative procedure. This nevertheless decreases tumor burden, facilitates symptom control, and prevents complications caused by bleeding, perforation, or bowel obstruction resulting from fibrosis. In the stomach (types I and II) and rectum endoscopic excision may be adequate provided the lesion(s) are local. Long-term therapy is focused on symptom alleviation and improvement of quality of life using somatostatin analogues, particularly in a subcutaneous depot formulation. In some instances interferons may have a role but their usage often is associated with substantial adverse events. Conventional chemotherapy and external radiotherapy either alone or in a variety of permutations are of minimal efficacy and should be balanced against the decrease in quality of life often engendered by such agents. Hepatic metastases may be amenable to surgery, radiofrequency ablation, or embolization either alone or in combination with chemotherapeutic agents or isotopically loaded microspheres. Rarely hepatic transplantation may be of benefit although controversy exists as to its actual use. Peptide-receptor-targeted radiotherapy for advanced disease using radiolabeled octapeptide analogs (111In/90Yt/177Lu-octreotide) appear promising but data are limited and its status remains investigational. A variety of antiangiogenesis and growth factor-targeted agents have been evaluated, but as yet have shown little promise. The keystone of current therapy remains the long-acting somatostatin analogues that alleviate symptomatology and substantially improve quality of life with minimal adverse effects.

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.

Conservation of the Notch1 signaling pathway in gastrointestinal carcinoid cells

Gastrointestinal (GI) carcinoid cells secrete multiple neuroendocrine (NE) markers and hormones including 5-hydroxytryptamine and chromogranin A. We were interested in determining whether activation of the Notch1 signal transduction pathway in carcinoid cells could modulate production of NE markers and hormones. Human pancreatic carcinoid cells (BON cells) were stably transduced with an estrogen-inducible Notch1 construct, creating BON-NIER cells. In the present study, we found that Notch1 is not detectable in human GI carcinoid tumor cells. The induction of Notch1 in human BON carcinoid cells led to high levels of functional Notch1, as measured by CBF-1 binding studies, resulting in activation of the Notch1 pathway. Similar to its developmental role in the GI tract, Notch1 pathway activation led to an increase in hairy enhancer of split 1 (HES-1) protein and a concomitant silencing of human Notch1/HES-1/achaete-scute homolog 1. Furthermore, Notch1 activation led to a significant reduction in NE markers. Most interestingly, activation of the Notch1 pathway caused a significant reduction in 5-hydroxytryptamine, an important bioactive hormone in carcinoid syndrome. In addition, persistent activation of the Notch1 pathway in BON cells led to a notable reduction in cellular proliferation. These results demonstrate that the Notch1 pathway, which plays a critical role in the differentiation of enteroendocrine cells, is highly conserved in the gut. Therefore, manipulation of the Notch1 signaling pathway may be useful for expanding the targets for therapeutic and palliative treatment of patients with carcinoid tumors.

GI carcinoid tumours: appearance of the primary and detecting metastases

Gastrointestinal carcinoid tumours are notoriously difficult to diagnose in the absence of the carcinoid syndrome. The clinical presentation is typically non-specific, and patients often go undiagnosed for years. Recent advances in computed tomography (CT), magnetic resonance (MR), endoscopic ultrasound, and nuclear scintigraphy have combined to improve the diagnosis and staging of this fascinating tumour. In this chapter the applications of cross-sectional imaging in patients with gastrointestinal carcinoid tumours is presented.

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%.

Insulin-like growth factor 1 signaling in human gastrointestinal carcinoid tumor cells

Background Insulin-like growth factor 1 (IGF-1) is an autocrine regulator of carcinoid tumors. Blockade of IGF-1 signaling has been proposed as a therapeutic target in the treatment of patients with carcinoid syndrome. We hypothesized that the induction of parallel raf-1/MEK1 pathways will block IGF-1-mediated chromogranin A (CgA) maintenance. Methods Human gastrointestinal carcinoid tumor cells (BON) were treated with IGF-1 (0-500 ng/mL). Raf-1/MEK1 activation was achieved with an estrogen-inducible raf-1 vector that was transduced into BON cells. Activation of IGF-1/raf-1 pathways was determined by phosphorylation of downstream targets p70s6 and ERK1/2. The secreted and intercellular levels of CgA were measured in conditioned media and whole cell extracts by Western and enzyme-linked immunosorbent assay analysis. Results IGF-1 and raf-1 pathways were activated successfully in BON cells, as shown by high levels of phosphorylated p70s6 and phosphorylated ERK1/2, respectively. Treatment of BON cells with IGF-1 stimulated the release of CgA, while high intracellular CgA levels were maintained. The activation of raf-1/MEK1 reversed the effect of IGF-1 treatment by the depletion of intracellular CgA. Conclusions The induction of the raf-1/MEK1 pathway blocks IGF-1-mediated intracellular neuroendocrine hormone regulation. Therefore, raf-1/MEK1 activation may be a viable method to block IGF-1-mediated cellular effects and serve as a therapeutic target in gastrointestinal carcinoid tumors.

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.

Updated population-based review of carcinoid tumors

OBJECTIVE

To determine the population-based incidence, anatomic distribution, and survival rates of gastrointestinal carcinoid tumors.

BACKGROUND

Carcinoid tumors arise from neuroendocrine cells and may develop in almost any organ. Many textbooks and articles represent single institution studies and report varying incidence rates, anatomic distribution of tumors, and patient survival rates. Population-based statistics remain largely unknown.

METHODS

Data was obtained from the National Cancer Institute Surveillance, Epidemiology, and End Results program (1973 to 1997). Incidence rates, distribution, and 5-year survival rates were analyzed. Multivariate Cox regression was used to identify predictors of survival using age, race/ethnicity, gender, and tumor characteristics (size, lymph node status, and stage).

RESULTS

Of the 11,427 cases analyzed, the average age was 60.9 years, and 54.2% were female. The overall incidence rates for carcinoid tumors have increased significantly over the past 25 years, although rates for some sites have decreased (eg, appendix). The gastrointestinal tract accounted for 54.5% of the tumors. Within the gastrointestinal tract, the small intestine was the most common site (44.7%), followed by the rectum (19.6%), appendix (16.7%), colon (10.6%), and stomach (7.2%). The 5-year survival rates for the most common gastrointestinal sites were stomach (75.1%), small intestine (76.1%), appendix (76.3%), and rectum (87.5%).

CONCLUSIONS

Using national, population-based cancer registry data, this study demonstrates that (1) incidence rates for carcinoid tumors have changed, (2) the most common gastrointestinal site is not the appendix (as is often quoted), but the small intestine, followed in frequency by the rectum, and (3) survival rates differ between individual anatomic sites.

A novel approach in the treatment of neuroendocrine gastrointestinal tumors: additive antiproliferative effects of interferon-gamma and meta-iodobenzylguanidine

BACKGROUND

Therapeutic options to effectively inhibit growth and spread of neuroendocrine gastrointestinal tumors are still limited. As both meta-iodobenzylguanidine (MIBG) and interferon-gamma (IFNgamma) cause antineoplastic effects in neuroendocrine gastrointestinal tumor cells, we investigated the antiproliferative effects of the combination of IFNgamma and non-radiolabeled MIBG in neuroendocrine gut STC-1 and pancreatic carcinoid BON tumor cells.

METHODS AND RESULTS

IFNgamma receptors were expressed in both models. IFNgamma dose- and time-dependently inhibited the growth of both STC-1 and of BON tumor cells with IC50-values of 95 +/- 15 U/ml and 135 +/- 10 U/ml, respectively. Above 10 U/ml IFNgamma induced apoptosis-specific caspase-3 activity in a time-dependent manner in either cell line and caused a dose-dependent arrest in the S-phase of the cell cycle. Furthermore, IFNgamma induced cytotoxic effects in NE tumor cells. The NE tumor-targeted drug MIBG is selectively taken up via norepinephrine transporters, thereby specifically inhibiting growth in NE tumor cells. Intriguingly, IFNgamma treatment induced an upregulation of norepinephrine transporter expression in neuroendocrine tumors cells, as determined by semi-quantitative RT-PCR. Co-application of sub-IC50 concentrations of IFNgamma and MIBG led to additive growth inhibitory effects, which were mainly due to increased cytotoxicity and S-phase arrest of the cell cycle.

CONCLUSION

Our data show that IFNgamma exerts antiproliferative effects on neuroendocrine gastrointestinal tumor cells by inducing cell cycle arrest, apoptosis and cytotoxicity. The combination of IFNgamma with the NE tumor-targeted agent MIBG leads to effective growth control at reduced doses of either drug. Thus, the administration of IFNgamma alone and more so, in combination with MIBG, is a promising novel approach in the treatment of neuroendocrine gastrointestinal tumors.

Neuroendocrine tumors of the appendix

The vast majority of neuroendocrine neoplasms of the appendix are carcinoid tumors. Most are of enterochromaffin (EC) cell type, although rare examples are of L cell type. EC cell carcinoids of the appendix differ from those encountered elsewhere in the gastrointestinal system. For example, they are remarkably common given the small size of the appendix, are usually benign, occur in younger patients, and typically contain sustentacular cells that express S-100. Origin from subepithelial neuroendocrine cells could explain these characteristics. It has also been suggested that most appendiceal carcinoids are hyperplastic rather than neoplastic, although this hypothesis requires further study. Nevertheless, truly neoplastic EC cell carcinoids of the appendix undoubtedly occur, and those greater than 2 cm in diameter have a significant risk of producing distant metastases. Carcinoid syndrome is a very rare presentation. Tubular carcinoids are unusual benign neoplasms; it has been proposed that they represent L cell carcinoids with a predominant tubular pattern of growth. Goblet cell carcinoids tend not to produce a grossly visible tumor mass but diffusely infiltrate the wall. They typically exhibit tight clusters of goblet cells, usually with scattered neuroendocrine cells and sometimes with Paneth cells, sometimes surrounding a small lumen. They may behave as a low-grade malignancy. The distinction between goblet cell carcinoid and other types of tumor is of great importance because of the implications for treatment and prognosis. Frank adenocarcinoma can arise from goblet cell carcinoids, and tumors with both components are classified as mixed goblet cell carcinoid-adenocarcinoma. The carcinoma component of the latter determines their prognosis, which would be worse than for a goblet cell carcinoid alone.

Nonsteroidal anti-inflammatory drugs inhibit growth of human neuroendocrine tumor cells via G1 cell-cycle arrest

Therapeutic options to inhibit growth of human NETs of the GEP system are limited. Since NSAIDs might provide an antiproliferative treatment alternative with acceptable toxicity, we examined the effects of different NSAIDs on growth and survival in a representative set of human GEP NET cell lines. Growth and apoptosis were determined based on cell numbers, cell-cycle analyses, kinase assays, DNA fragmentation and PARP cleavage. Expression of COX and cell cycle-regulatory molecules was examined by immunoblotting and reporter gene assays. Depending on the drug and cell line investigated, NSAID treatment resulted in profound growth inhibition of GEP NET cells. Growth-inhibitory effects were achieved with either COX-2 selective (NS398) or unselective (indomethacin, sulindac) compounds. Cell-cycle analyses documented a G1 arrest in NSAID-treated GEP NET populations. In addition, 100 microM sulindac or indomethacin induced apoptosis. All 3 COX inhibitors prevented CDK-2 activation. In parallel to the NSAID-mediated reduction of CDK-2 activity, p21(cip-1) promoter activity and cellular p21(cip-1) levels increased and p21(cip-1) was sequestered into CDK-2 complexes. Thus, the G1 arrest likely resulted from p21(cip-1)-dependent inhibition of CDK-2 activity. At therapeutically relevant concentrations, sulindac significantly reduced GEP NET cell numbers, whereas IFN-alpha and octreotide remained ineffective. The extent of growth inhibition in GEP NETs was comparable to the antiproliferative effects of sulindac in established NSAID-sensitive cell models. NSAIDs acted as potent antiproliferative agents in GEP NET cells via G1 cell-cycle arrest and might therefore offer a therapeutic alternative to current treatment modalities.

Pedunculated rectal carcinoid removed by endoscopic mucosal resection: a case report

Carcinoid tumors generally appear as yellow/gray or tan submucosal nodules. We experienced a case of pedunculated rectal carcinoid showing a mushroom-like appearance. The case was a forty years old woman who was admitted to our hospital due to rectal bleeding. Colonoscopy revealed a pedunculated polyp presenting a mushroom-shaped appearance measuring 13 mm in diameter in the rectum. The histological diagnosis of specimens obtained by biopsy was adenocarcinoma and transanal ultrasonography revealed the tumor localization within the submucosal layer in the rectum. Endoscopic mucosal resection (EMR) was performed. Histopathological examination established the diagnosis of carcinoid tumor in the rectum. Frequencies of the pedunculated type in rectal carcinoids were reported to be 2.4% to 7.1% in the literature. Because of its rarity, pedunculated configuration may confuse the endoscopic diagnosis of carcinoids. Treatment for carcinoids of 1 to 1.5 cm in size remains controversial. Although such tumors are technically respectable by EMR, careful attention must be paid in dealing with these tumors because there may be unexpected behaviors of the tumors.

Gasless, video endoscopic transanal excision for carcinoid and laterally spreading tumors of the rectum

BACKGROUND

The aim of this study is to determine whether gasless, video endoscopic transanal-rectal tumor excision (gasless VTEM) is a valid treatment for rectal carcinoid and laterally spreading tumors (LST).

METHODS

Eighty-four patients with an adenoma, adenocarcinoma (Tis/T1), or carcinoid tumor of the rectum were divided into three groups: (i) LST ( n = 17 patients), (ii) carcinoid ( n = 11), and (iii) control with other types of tumors ( n = 56).

RESULTS

The LST group had a longer median operating time than in the control group, whereas the carcinoid group had a shorter operating time. Two patients (11.7%) in LST group developed peritoneal entry during the operation, while 2 patients (3.6%) in the control group experienced postoperative complications. During a median follow-up length of 55.2 months, one patient in the LST group developed a recurrence.

CONCLUSIONS

Gasless VTEM is a simple, minimally invasive procedure used to treat LST and carcinoid tumors of the rectum. However, resection for the LST group had a high risk of peritoneal entry during operation.

Raf-1 activation suppresses neuroendocrine marker and hormone levels in human gastrointestinal carcinoid cells

Gastrointestinal carcinoid cells secrete multiple neuroendocrine markers and hormones including 5-HT and chromogranin A. The intracellular signaling pathways that regulate production of bioactive molecules are not completely understood. Our aim was to determine whether activation of the raf-1/MEK/MAPK signal transduction pathway in carcinoid cells could modulate production of neuroendocrine markers and hormones. Human pancreatic carcinoid cells (BON) were stably transduced with an estrogen-inducible raf-1 construct creating BON-raf cells. Activation of raf-1 in BON-raf cells led to a marked induction of phosphorylated MEK and ERK1/2 within 48 h. Importantly, raf-1 activation resulted in morphological changes accompanied by a marked decrease in neuroendocrine secretory granules by electronmicroscopy. Moreover, induction of raf-1 in BON-raf cells led to significant reductions in 5-HT, chromogranin A, and synaptophysin levels. Furthermore, treatment of BON-raf cells with MEK inhibitors PD-98059 and U-0126 blocked raf-1-mediated morphological changes and hormone suppression but not ERK1/2 phosphorylation. These results show that raf-1 induction suppresses neuroendocrine marker and hormone production in human gastrointestinal carcinoid cells via a pathway dependent on MEK activation.

Minimally invasive surgery for carcinoid tumors in the rectum

Most carcinoid tumors of the rectum are confined to the submucosa with a size less than 1-2 cm and are usually suitable for local excision, as metastasis to the regional nodes is limited. Endoscopic excision of carcinoid tumors has been performed for this entity as a least invasive method but incomplete resection and/or unclear surgical margin and curability have been reported to occur in 24-42% of cases because of a limited resection up to the submucosal layer and burn effect. Transanal local excision has often been applied for rectal carcinoid tumor as a least invasive method among local excision procedures to accomplish full thickness excision for determining the curability. However, it is often difficult to obtain free access with a sufficient surgical field by the conventional method. Transanal endoscopic microsurgery (TEM) has appeared as a useful option to access a high tumor with fine visibility but special caution has to be taken for tumors sited above the peritoneal reflection. To facilitate full thickness excision even for high tumors, novel local excisional technique called minimally invasive transanal surgery (MITAS) has been developed and used for local removal of carcinoid tumors in the rectum. A specially designed anal retractor connected to the Octopus retractor holder with several novel techniques facilitated excisional procedures around the anus with a sufficient fixed surgical field and an ENDO-stapler allowed the simultaneous excision and anastomosis to be performed. The technique facilitated total excisional biopsy with less operative time and blood loss, and no mobility or mortality in 12 patients with rectal carcinoid tumors.