Gastrointestinal carcinoid tumors: current management strategies

Endoscopic mucosal dissection for multiple rectal carcinoids: A case report

BACKGROUND

Multiple rectal carcinoids have a low incidence clinically. Curative resection can be achieved by endoscopy, but there is a risk of missing the lesion. Postoperative follow-up is very important.

CASE SUMMARY

A patient was diagnosed with multiple rectal carcinoids and hemorrhoids by colonoscopy due to repeated hematochezia for more than 2 mo. After chest, abdominal and pelvic contrast-enhanced CT examinations were completed to exclude carcinoid metastasis, endoscopic lesion resection was performed. A total of eight lesions were completely removed. Postoperative pathology and immunohistochemistry confirmed carcinoids, classified as G1. No new lesions were found by colonoscopy 3 mo after operation.

CONCLUSION

For multiple rectal carcinoids smaller than 1 cm, endoscopic dissection can be curative, but close follow-up should be performed.

Ligation-assisted endoscopic mucosal resection has high complete resection rate in rectal carcinoid tumor

AIM

We aimed to compare the outcomes of different therapeutic modalities in rectal carcinoid tumors.

METHOD

We retrospectively collected 145 patients with rectal carcinoid tumors which were pathologically diagnosed from 2005/01/01 to 2016/12/31. We compared tumor size, complete resection rate and recurrent rate between different therapeutic modalities. Then, prospectively compared the treatment outcomes of 28 patients treated with ligation assisted endoscopic mucosal resection (LEMR) and 25 patients treated with endoscopic mucosal resection with cap (EMRC).

RESULT

The mean size of tumors was 6.5 mm (1-25 mm), and the mean follow-up duration was 26 months (6-118 months). The therapeutic modalities included ligation-assisted endoscopic mucosal resection (LEMR) (25 tumors, 17%), endoscopic mucosal resection (EMR) (31 tumors, 21%), snare polypectomy (30 tumors, 21%), biopsy forceps removal (46 tumors, 32%) and surgical resection (13 tumors, 11%), including 6 tumors treated with transanal endoscopic microsurgery (TEM) method. In view of pathologically complete resection rate, LEMR was highest (100%), followed by surgical resection (85%). However, EMR only had 42% pathologically complete resection rate. Besides, LEMR and surgical resection had no local recurrence and significantly higher clinically complete resection rate, compared to other treatments. For the further prospective study, complete resection was noted in 28 (100%) patients in LEMR group and 13 (52%) patients in EMRC group.

CONCLUSION

In the treatment of rectal carcinoid tumors, LEMR is safe and effective compared with traditional endoscopic treatments.

A Multifocal Pattern of Neuroendocrine Neoplasms Along the Appendix: A Series of Six Cases

We present 6 cases with multifocal appendiceal neuroendocrine tumors, including their clinical and histopathological findings. To our knowledge, this is the first description of a multifocal pattern of a neuroendocrine neoplasm arising in the appendix. All patients presented in a setting requiring an acute appendectomy. The number of tumors ranged from 2 to 5. Histopathological examination revealed WHO (World Health Organization) grade 1 tumor in 3 patients and WHO grade 2 in the other 3 patients. The median duration of follow-up in these patients was 70 months (range = 6-192 months). No metastatic disease was observed. According to these findings, a multifocal pattern of neuroendocrine neoplasms along the appendix seems not to be a predictor for local advanced or metastatic disease.

Usefulness of Capsule Endoscopy and Double-balloon Enteroscopy for the Diagnosis of Multiple Carcinoid Tumors in the Small Intestine: Case Reports and a Literature Review

The incidence of carcinoid tumor in the small intestine is increasing; however, its preoperative diagnosis is difficult. We recently experienced three cases of multiple carcinoid tumors in the small intestine successfully detected using capsule endoscopy (CE), followed by a pathological diagnosis using double-balloon enteroscopy (DBE). To diagnose multiple carcinoid in the small intestine appropriately, we reviewed the information of five cases reported to date along with our three recent cases. The literature review demonstrated that CE and DBE are useful for detecting and diagnosing small intestinal carcinoids and tumor multiplicity, which aids in determining the appropriate resection range.

Multiple rectal neuroendocrine tumors: report of five cases

Carcinoids are slow growing neuroendocrine tumors (NET) originating in the enterochromaffin cells of the gastrointestinal tract. In previous studies, rectal NET comprised only about 1% of all anorectal neoplasms; however, the incidence of rectal NET has shown a recent increase. Typically, rectal NET presents as a single subepithelial nodule, and multicentricity of rectal NETs is rare, with reported incidence of 2-4.5%. Due to the rarity of multiple rectal NETs, there is no consensus or guidelines for treatment of multiple rectal NETs. However, NETs of the rectum that are less than 10 mm in diameter and do not infiltrate the muscularis propria, without distant metastasis, can be removed by endoscopy, as with solitary rectal NET. We encountered five cases of multiple rectal NETs which were treated successfully by endoscopy.

An unusual case of synchronous carcinoid of ovary and gall bladder

Multifocal carcinoid is a known phenomenon. We present a rare combination of an ovarian carcinoid synchronous with gallbladder carcinoid. This rare combination has not been reported so far. An asymptomatic 45-years-old perimenopausal lady was diagnosed to have a metastatic ovarian cancer, but on laparotomy she was found to have a primary synchronous metastatic gall bladder as well. On histopathological evaluation she was found to have two separate primary carcinoids. Subsequently the patient received chemotherapy and is completely asymptomatic on follow up. Further research needs to be undertaken and guidelines need to be formulated for management of these cases.

Multiple carcinoid tumors of the small intestine preoperatively diagnosed by double-balloon endoscopy

Background

Multiple carcinoid tumors of the small intestine are rare and are very difficult to detect preoperatively.

Case Report

A 75-year-old woman in whom the bleeding focus could not be found by upper and lower endoscopy and abdominal CT was admitted for evaluation of anemia. We examined the patient with total double-balloon endoscopy (DBE) and located multiple submucosal tumors. The multiple carcinoid tumors were resected successfully under laparoscopy.

Conclusions

We report a case of a successful laparoscopic operation for multiple carcinoid tumors in the small intestine without intraoperative endoscopy. Total digestive tract observation using DBE is very useful for laparoscopic operation for multiple tumors in the small intestine.

Rare anorectal neoplasms: gastrointestinal stromal tumor, carcinoid, and lymphoma

Several uncommon tumors occur in the anal canal such as gastrointestinal stromal tumors, carcinoids, and lymphoma. Increased clinical experience and advancements in molecular biology have improved the accuracy of pathologic diagnosis and guided treatment recommendations, which the author addresses in this article.

Biogenic amines serotonin and dopamine regulate cholangiocyte hyperplastic and neoplastic growth

Biogenic amines, such as serotonin and dopamine, regulate a multitude of cellular responses. A great deal of effort has been invested into understanding the effects of these molecules and their corresponding receptor systems on cholangiocyte and cholangiocarcinoma secretion, apoptosis and growth. This review summarizes the results of these efforts and highlights the importance of these regulatory molecules on the physiology and pathophysiology of cholangiocytes. Specifically we have focused on the recent findings into the effects of serotonin and dopamine on cholangiocyte hyperplasia and neoplastic growth.

Serotonin metabolism is dysregulated in cholangiocarcinoma, which has implications for tumor growth

Cholangiocarcinoma is a devastating cancer of biliary origin with limited treatment options. Symptoms are usually evident after blockage of the bile duct by the tumor, and at this late stage, they are relatively resistant to chemotherapy and radiation therapy. Therefore, it is imperative that alternative treatment options are explored. We present novel data indicating that the metabolism of serotonin is dysregulated in cholangiocarcinoma cell lines, compared with normal cholangiocytes, and tissue and bile from cholangiocarcinoma patients. Specifically, there was an increased expression of tryptophan hydroxylase 1 and a suppression of monoamine oxidase A expression (enzymes responsible for the synthesis and degradation of serotonin, respectively) in cholangiocarcinoma. This resulted in an increased secretion of serotonin from cholangiocarcinoma and increased serotonin in the bile from cholangiocarcinoma patients. Increased local serotonin release may have implications on cholangiocarcinoma cell growth. Serotonin administration increased cholangiocarcinoma cell growth in vitro, whereas inhibition of serotonin synthesis decreases tumor cell growth both in vitro and in vivo. The data presented here represent the first evidence that serotonin metabolism is dysregulated in cholangiocarcinoma and that modulation of serotonin synthesis may represent an alternative target for the development of therapeutic strategies.

Radio-guided surgery in neuroendocrine tumors

The majority of Neuroendocrine tumors (NET) express somatostatin (SS) receptors, and thus can be successfully targeted with radiolabeled SS analogs in vivo. Somatostatin receptor scintigraphy (SRS) with (111)In-DTPA Octreotide is the main imaging technique for evaluation of NETs. Radio-guided surgery for NETs, therefore, primarily utilizes (111)In-DTPA Octreotide tumor localization mechanism and kinetics. Somatostatin analog radiopharmacy continues to evolve to include the development of more selective and higher affinity analogs and PET tracers. These changes are expected to open new venues for radio-guided surgery technology.

[Recurring, severe upper abdominal pain in a 45 year old patient]

A 45-year-old patient presented with a history of recurrent abdominal pain of unknown origin. The CT scan of the abdomen demonstrated a thickened mesenteric root and a segmental ileus of the jejunum. Laparotomy revealed a neuroendocrine tumour of the small bowel. Such tumours are rare causes of recurrent abdominal pain. Especially when the CT scan of the abdomen reveals mesenteric abnormalities (desmoplastic reaction) and/or a segmental ileus, a neuroendocrine tumour of the small bowel should be considered. The therapy of choice is resection of the tumour followed by systemic therapy including somatostain analogues and chemotherapy in the case of a hormone secreting tumour or metastases.

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.

Neuroendocrine tumours (carcinoids) of the appendix

Neuroendocrine tumours (NETs) of the appendix (formerly 'carcinoids') are rare and are usually detected incidentally after appendectomy. Histopathologically they derive from a subepithelial cell population, which is different from NETs in other sites. They are preferentially located at the tip of the appendix. Tumours <1 cm hardly ever metastasize and are treated by appendectomy. Tumours >2 cm require right hemicolectomy because of a significant risk of metastatic spread. Treatment for lesions 1-2 cm is controversial and needs further characterization of the tumour (i.e. mesoappendiceal invasion, vascular invasion, mitotic activity, proliferation markers) and careful patient risk evaluation. Goblet-cell carcinoids have features resembling both carcinoid and adenocarcinoma and should be treated by hemicolectomy. Overall prognosis of small appendiceal NET is excellent in all ages.

Surgical treatment of peritoneal carcinomatosis from well-differentiated digestive endocrine carcinomas

BACKGROUND

The presence of peritoneal carcinomatosis (PC) in association with endocrine carcinomas (EC) is generally considered to have no impact on life expectancy, contrary to liver metastases. This study was aimed at assessing the actual prognostic impact of PC and to evaluate a new treatment with respect to survival times.

PATIENTS AND METHODS

Among 111 patients undergoing surgery for progressive, well-differentiated EC, 37 (33%) presented a histologically proven PC, with synchronous liver metastases in 36 of them. The origin was ileal or appendiceal (carcinoid tumors) in at least 81% of cases. The patients were divided into 2 groups. Patients in group 1 (n = 20) could not undergo complete resection of PC, while those in group 2 (n = 17) underwent complete cytoreductive surgery, followed by immediate intraperitoneal chemotherapy. Partial hepatectomy was performed in 65% of patients in group 2. The median follow-up was 6.9 years.

RESULTS

There was no postoperative mortality, and the morbidity rate was 47%. In group 1, 15 of the 20 patients died (5-year survival rate, 40.9%). Deaths were caused either by liver failure (60% of patients) or bowel obstruction from PC (40%). In group 2, six of the 17 patients died (5-year survival rate, 66.2%; P = .007). These patients died of liver failure (n = 4, 23.5%), bowel obstruction (n = 1, 5.8%), and cerebral hemorrhage (n = 1, 5.8%).

CONCLUSIONS

PC associated with EC is not a rare event; it is mainly caused by carcinoid tumors and is always associated with liver metastases. When present, PC is the direct cause of death in 40% of patients if no specific treatment is undertaken. Treatment of PC with maximal cytoreductive surgery and immediate intraperitoneal chemotherapy appears promising, even though it can only be considered as palliative.

Gastrointestinal carcinoid tumors: factors that predict outcome

Gastrointestinal (GI) carcinoids are neuroendocrine tumors originating in multiple locations throughout the GI tract. The prognosis for patients with GI carcinoid tumors is diverse. To determine the factors that significantly affect prognosis, we reviewed our experience. Between 1992 and 2000 a total of 70 patients with GI carcinoid tumors underwent surgical resection at our institution. The patients were grouped into three categories based on the origin of the carcinoid tumor: foregut, midgut, hindgut. The mean age of the patients was 56 +/- 2 years. All patients with foregut carcinoids had symptoms upon presentation, whereas 61% of those with midgut carcinoids and only 37% of those with hindgut carcinoids had symptoms ( p < 0.001). The factors that most strongly affected survival on univariate analysis were a symptomatic presentation and the site of origin. Patients with foregut or midgut lesions had lower 5-year disease-free survivals than those with hindgut tumors. Moreover, the size of the primary tumor and the presence of liver metastases were not independent predictors of survival. Despite the larger tumor size and the higher incidence of liver metastases, patients with foregut carcinoids appear to have the same prognosis as those with midgut carcinoids. These data therefore suggest that the outcomes of patients with carcinoid tumors are highly dependent on the presence of symptoms and the site of origin.

Basis for treatment of functioning neuroendocrine tumours

A general characteristic of GEP endocrine tumours is that vast majority produce and secrete a multitude of peptide hormones and amines. The rarity of these types of tumours, their possible episodic expression and the variable clinical symptoms, are the reasons why patients are often diagnosed late in the advanced stages of the disease. For these reasons, the patients with advanced metastatic disease should be treated aggressively with medical and surgical therapies aimed at reducing both symptoms and complications through strategies that reduce tumour bulk and block hormonal effects. The medical treatment of functioning endocrine tumours of the gastrointestinal tract must be based on the growth properties of the tumour and includes chemotherapy, somatostatin analogs, alpha-interferon alone and associated with somatostatin analogs, chemoembolization and radiolabelled somatostatin analogs. Even if chemotherapy has been basis of therapy for these types of tumours for a long time, it is currently reserved for progressive disease and anaplastic tumours. Biotherapy, with interferon and somatostatin analogs has been demonstrated to have a significant antitumor effect and causes an improvement of symptoms in patients with functioning neuroendocrine tumours. Furthermore, these drugs produce a notable improvement in the quality of life. Radioactive targeting therapy is the most promising new treatment modality for patients who have SST receptor positive tumours.

Carcinoid--a comprehensive review

Carcinoid tumors originate from the neuroendocrine cells throughout the body and are capable of producing various peptides. Their clinical course is often indolent but can also be aggressive and resistant to therapy. We examined all aspects of carcinoid tumors including the molecular biology oncogenesis, role of angiogenesis, recent advances in imaging, and therapy. The Medline and Cancerlit databases were searched using carcinoid as the keyword. English language manuscripts were reviewed and relevant references from a total of 7741 were found. All titles were screened and all the relevant manuscripts were analyzed; we found 307 references pertinent to the history, epidemiology, clinical behavior, pathology, pathophysiology, molecular biology, radiologic imaging, supportive care of carcinoid syndrome, and results of therapeutic clinical trials. Management of patients with carcinoid tumors requires an understanding of the disease process and a multimodality approach. Introduction of long-acting somatostatin analogues has resulted in significant advances in the palliative care of patients with carcinoid syndrome. However, advanced carcinoid tumor remains incurable. Existing therapies for advanced disease have low biologic activity, high toxicity, or both. Clearly, more research is necessary in the areas of molecular biology, targeted therapy, and development of new drugs Future advances in this field need to focus on clinical and biological predictors of outcome. Early works in the area of tumor biology such as the role of p53, bcl-2, bax, MEN1, FGF TGF PDGF and VEGF expression are of interest and need to be explored further.

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.

Serum peptide profiles in patients with carcinoid tumors

BACKGROUND

Patterns of elevated serum peptides may reveal additional markers and permit better classification of tumors based on (secondary) peptide secretion.

METHODS

Fasting peptide profiles were obtained from 31 carcinoid patients. vasoactive intestinal peptide (VIP), pancreatic polypeptide (PP), neurotensin, substance P, gastrin-releasing polypeptide (GRP), calcitonin, gastrin, and pancreastatin were measured. Peptide elevation patterns were correlated with disease sites, syndrome, and survival.

RESULTS

Elevations in patients were as follows: VIP 0%, PP 13%, neurotensin 10%, substance P 20%, GRP 3%, calcitonin 10%, and gastrin 3%. There were no consistent patterns of elevated peptides with regard to site or syndrome. Pancreastatin was elevated in 81% of profiles and was the only abnormal peptide in 57% of patients.

CONCLUSION

Peptide profile results do not permit improved classification, predict syndrome development, or correlate with survival. In contrast, pancreastatin is elevated in most cases and may be utilized to monitor disease progression and evaluate response to therapy.

Solitary versus multiple carcinoid tumors of the ileum: a clinical and pathologic review of 68 cases

It is well known that small intestinal carcinoid tumors may occur as solitary or multiple lesions. However, the biologic significance of multiple carcinoid tumors has not been clearly defined. The purpose of this study was to compare the clinical and pathologic features and prognosis of patients with solitary versus multiple carcinoid tumors of the ileum. Sixty-eight patients, including 50 with solitary and 18 with multiple carcinoid tumors, were included in the study. Hematoxylin and eosin-stained slides from routinely processed tumor resection specimens of the ileum were evaluated for a variety of histologic features such as tumor size, depth of invasion, tumor stage, and venous, perineural, and lymphovascular invasion. Follow-up and clinical data, such as patient age, gender, presenting complaints, presence of synchronous or metachronous malignancies, and presence of the carcinoid syndrome, were obtained and the results were compared between the two patient groups. Fifty patients with solitary carcinoid tumors (male/female ratio, 27:23) and 18 patients with multiple tumors (male/female ratio, 7:11) were identified. Patients with multiple carcinoid tumors were significantly younger than patients with solitary tumors at the time of diagnosis (55 years vs 63 years, p = 0.006). There was a high association between multiple carcinoid tumors and the carcinoid syndrome (4 of 18 vs 1 of 50, p = 0.004) as compared with patients with solitary carcinoid tumors. There was also an association between tumor multiplicity and venous invasion, but this relationship was not statistically significant (p = 0.07). The follow-up period was similar for both groups (mean 36 months, median 26 months, range 1-139 months). A significantly higher proportion of patients with multiple carcinoid tumors were either alive with disease or died of disease (56%) compared with those with solitary carcinoid tumors (18%, p = 0.002), and this relationship persisted in multivariate analysis (p = 0.02). Overall, no significant differences were observed between these two patient groups with respect to other clinicopathologic features such as tumor size, depth of invasion, presence of distant metastases, lymphatic or perineural invasion, or presence of an associated malignancy (p >0.05). In conclusion, we found that patients with multiple carcinoid tumors are younger, have a significantly greater risk of developing the carcinoid syndrome, and have a poorer prognosis than patients with solitary tumors.

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.

Whole-body 18F dopa PET for detection of gastrointestinal carcinoid tumors

PURPOSE

To evaluate fluorine 18 (18F) dopa positron emission tomography (PET) in comparison with established imaging procedures in gastrointestinal carcinoid tumors.

MATERIALS AND METHODS

After evaluation of the normal distribution of 18F dopa, 17 patients with histologically confirmed tumors were examined with 18F dopa PET. Results of 2-[fluorine 18]fluoro-2-deoxy-D-glucose (FDG) PET, somatostatin-receptor scintigraphy, and morphologic imaging (computed tomography and/or magnetic resonance imaging) were available for all patients. Results of the procedures were evaluated by two radiologists and two nuclear medicine specialists, whose consensus based on all available histologic, imaging, and follow-up findings was used as the reference standard.

RESULTS

Ninety-two tumors were diagnosed: eight primary tumors, 47 lymph node metastases, and 37 organ metastases. 18F dopa PET led to 60 true-positive findings (seven primary tumors, 41 lymph node metastases, 12 organ metastases); FDG PET, 27 (two primary tumors, 14 lymph node metastases, 11 organ metastases); somatostatin-receptor scintigraphy, 52 (four primary tumors, 27 lymph node metastases, 21 organ metastases); and morphologic imaging, 67 (two primary tumors, 29 lymph node metastases, 36 organ metastases). This resulted in the following overall sensitivities: 18F dopa PET, 65% (60 of 92); FDG PET, 29% (27 of 92); somatostatin-receptor scintigraphy, 57% (52 of 92); morphologic procedures, 73% (67 of 92). Although the morphologic procedures were most sensitive for organ metastases, 18F dopa PET enabled best localization of primary tumors and lymph node staging.

CONCLUSION

18F dopa PET is a promising procedure and useful supplement to morphologic methods in diagnostic imaging of gastrointestinal carcinoid tumors.

Genomic alterations in well-differentiated gastrointestinal and bronchial neuroendocrine tumors (carcinoids): marked differences indicating diversity in molecular pathogenesis

Neuroendocrine tumors (carcinoids) are a heterogeneous group of neoplasms arising from the diffuse neuroendocrine system. Genetic changes underlying their tumorigenesis are primarily unknown. We used comparative genomic hybridization to screen 32 well-differentiated neuroendocrine tumors (21 gastrointestinal and 11 bronchial) and three associated metastases for genomic alterations. There were striking differences of genomic imbalances between the two subgroups of neuroendocrine tumors. Losses of chromosome 18q and 18p were shown in eight (38%) and seven (33%), respectively, out of 21 gastrointestinal tumors and in none of the 11 bronchial tumors. Conversely, deletions of 11q occurred in four of 11 (36%) bronchial tumors but only in one gastrointestinal tumor. These comparative genomic hybridization findings were confirmed by interphase cytogenetics. Our data indicate that neuroendocrine tumors of the two subgroups develop via different molecular pathways. Inactivation of one or several tumor suppressor genes on chromosome 18 may be important for the biological behavior of gastrointestinal tumors, whereas gene inactivation on 11q seems to be associated with tumor development of the bronchi.

Tumores neuroendócrinos do trato gastrointestinal

Os tumores neuroendócrinos (TNE) já foram considerados raridades. Atualmente, através de novas técnicas para seu reconhecimento, tem-se identificado um número crescente destas neoplasias, sendo possível estratificá-las em subgrupos, expandindo o espectro dos neoplasmas neuroendócrinos e sua importância na prática cirúrgica atual. A imunocitoquímica, a dosagem de peptídeos e os modernos métodos de imagem proporcionam informações imprescindíveis para um diagnóstico acurado e o tratamento adequado. Este artigo tem por objetivo revisar aspectos referentes aos tumores neuroendócrinos do trato gastrointestinal relativos à história, fisiopatologia, classificação atualizada, diagnóstico e tratamento.

Carcinoid syndrome with unknown primary: a case report

Carcinoid syndrome usually is associated with a classic presentation, the diagnosis of which is supported by elevations in neuroendocrine substances such as 5-hydroxyindoleacetic acid and by localization and pathologic identification of a neuroendocrine tumor. The authors report a patient for whom there was a 7-year delay in diagnosis and even then a primary tumor could not be localized.

Recent advances in systemic therapy for gastrointestinal neuroendocrine tumors

Neuroendocrine tumors of the gastrointestinal tract are rare tumors which can be classified as amine precursor uptake and decarboxylation tumors (APU-Domas). Although the majority of clinically apparent tumors are malignant, they are frequently slow growing. Despite this characteristic, they may generate disabling hormonal syndromes requiring aggressive treatment to achieve palliation. Recent advances in understanding the pathophysiology of these tumors has led to better medical therapy with chemotherapeutic agents, somatostatin analogues, and biologic therapies. This review will update the recent efforts in systemic therapies of the gastrointestinal neuroendocrine tumors.

A novel cytotoxic agent for human carcinoid tumors

BACKGROUND

Conventional adjuvant therapy for advanced carcinoid tumors remains disappointing; novel therapeutic agents are needed. We have shown previously that inhibiting polyamine biosynthesis with alpha-difluoromethylornithine (DFMO) slows the growth of carcinoid tumors. However, the clinical utility of DFMO has been limited by its cytostatic property. Synthetic polyamine analogs such as 1,19-bis(ethylamino)-5,10,15-triazanonadecane (BE-4-4-4-4) appear to be cytotoxic against several human tumors. The purpose of our study was to determine whether BE-4-4-4-4 is a more effective antiproliferative and cytotoxic agent than DFMO on human carcinoid (BON) cells in vitro.

METHODS

BON cells were treated with either 5 mmol/L DFMO, 0.5 to 10 mumol/L BE-4-4-4-4, or vehicle (control). Ornithine decarboxylase activity was determined by the rate of 14CO2 production, and intracellular polyamine levels were determined by chromatography. Cell number and viability were determined by Coulter counter and trypan blue exclusion, respectively.

RESULTS

BE-4-4-4-4 inhibited ornithine decarboxylase activity and depleted all 3 polyamines. BE-4-4-4-4 decreased cell numbers by 81% compared with control and 27% compared with DFMO. BE-4-4-4-4 also induced a 2-fold increase in cell death compared with control or DFMO.

CONCLUSIONS

BE-4-4-4-4 is cytotoxic and more effective than DFMO in inhibiting growth of BON cells. Polyamine analogs such as BE-4-4-4-4 may be effective adjuvant therapeutic agents for advanced carcinoid tumors.