Management of gastroenteropancreatic endocrine tumors: the place of somatostatin analogues

Multimodal Treatment of Vasoactive Intestinal Polypeptide-producing Pancreatic Neuroendocrine Tumors with Liver Metastases

A 53-year-old man presented with diarrhoea and hypokalaemia and was diagnosed with a neuroendocrine tumour of unknown origin with multiple liver metastases. Somatostatin analogues led to a reduction in the size of the tumours and improvement of his symptoms. However, after several years, the tumours grew in size, and the patient's clinical symptoms recurred. The patient underwent transcatheter arterial embolization (TAE) of the hepatic artery to treat the liver metastases. Immediately after embolization, the symptoms disappeared. Although the patient had an unresectable vasoactive intestinal polypeptide-producing neuroendocrine tumour, the endocrine symptoms were able to be controlled with chemotherapy and TAE, resulting in a long-term survival.

Surgical resection of vasoactive intestinal peptideoma with hepatic metastasis aids symptom palliation: A case report

Vasoactive intestinal peptideoma (VIPoma) is a rare pancreatic endocrine tumor associated with a well-defined clinical syndrome characterized by watery diarrhea, hypokalemia and metabolic acidosis. In adults, VIPoma is most commonly found in the pancreas, with 80% of the tumors occurring in the body and tail and 20% occurring in the pancreatic head. VIPomas can represent a significant diagnostic challenge due to their nonspecific clinical presentation, which can result in the misdiagnosis of a VIPoma as another condition, such as laxative overdose or a carcinoid secreting tumor. Surgical clearance of the tumor is the first-line treatment, even in cases with metastasis. The present study describes the case of a patient who presented with chronic watery diarrhea and hypokalemia due to a tumor in the pancreatic head, which was confirmed to contain immunoreactive vasoactive intestinal polypeptide via immunohistochemistry. A hepatic metastasis lesion was diagnosed following computed tomography. Stable control of symptoms was achieved after surgery and drug treatment. The study additionally reviews the clinical, histological, radiological and diagnostic features of the condition, as well as the therapeutic modalities that can be used to treat VIPoma in the pancreatic head with hepatic metastasis.

Role of Somatostatin Analogs in the Management of Neuroendocrine Tumors

Neuroendocrine tumors are rare neoplasms. During the last two decades, somatostatin analogs, exerting their activity through both receptor binding and enzymatic inhibition mechanisms, have been a key option in the management of neuroendocrine tumors. The treatment of neuroendocrine tumors with high doses of somatostatin analogs determined high rates of tumor stabilization, but the dose-response of somatostatin analogs on symptomatic relief and stabilization of tumor growth remains unpredictable. Several studies have indicated a higher efficacy of somatostatin analogs in well-differentiated, low-grade malignancy tumors that express a high density of somatostatin receptors. Synthesis of new, more effective molecules, with different pharmacokinetic profiles, receptor affinity and binding stability, will ease the clinician's tasks and improve patient expectancies in terms of survival and quality of life. Further studies are needed to clarify mechanisms underlying the better antiproliferative effect of higher doses of somatostatin analogs and to determine the optimum dose to saturate specific receptor subtypes

Canine gastrinoma: a case study and literature review of therapeutic options

CASE HISTORY

A 6.2 kg, 8-year-old, spayed female Australian Terrier was presented with weight loss, inappetence, lethargy and a 2-day history of intermittent vomiting.

CLINICAL FINDINGS

The dog had cranial abdominal pain and there was melaena present on digital rectal examination. Haematology revealed a marked, acute leucogram.

DIAGNOSIS AND TREATMENT

Fasting serum gastrin levels were markedly elevated and gastrinoma was suspected. Treatment was initiated with omeprazole, ranitidine and sucralfate. The dog remained clinically normal for 26 months, at which time exploratory surgery was undertaken and the dog subsequently euthanised due to extensive metastases. Histopathology and immunocytochemistry confirmed the diagnosis of metastatic gastrinoma.

CLINICAL RELEVANCE

This is a rare condition infrequently reported. Although the number of cases treated with omeprazole are too few to draw firm conclusions, it would appear that proton pump inhibitors are useful and should be considered for cases of gastrinoma managed medically. Long-term prognosis is poor, and survival times range from 1 to 147 weeks. Many treatment options are discussed in the medical literature though not all are feasible in veterinary patients.

Metastatic glucagonoma: Treatment with liver transplantation

Glucagonoma is a rare pancreatic endocrine tumor that is often both well developed and malignant at detection. In the case of metastatic spread the patient has a poor long-term prognosis. We hope to familiarize dermatologists and other specialists with this rare and potentially fatal disorder because early recognition of necrolytic migratory erythema, a clinical feature that may appear in patients with glucagonoma, can lead to possible cure, whereas delayed identification of the disease is associated with metastatic disease and a poor prognosis. We report the case of a 57-year-old patient with a metastatic glucagon-producing tumor; necrolytic migratory erythema was diagnosed and was successfully treated by a multimodal intervention including liver transplantation. Currently, 72 months after transplantation, our patient is in complete remission, which has been verified by somatostatin receptor scintigraphy monitoring, computed tomographic scanning and glucagon serum control. Increased awareness of the clinical symptoms and visible polymorphic mucocutaneous and nonspecific histopathologic features of glucagonoma syndrome is needed to avoid unnecessary delay in the diagnosis of this syndrome.

Diagnosis and treatment of VIPoma in a female patient

We report a case of VIPoma in an 83-year-old female patient, who presented with frequent and excessive diarrhoea, muscle weakness, and severe hypokalaemia. Abdominal computed tomography (CT) revealed a 4x6 cm mass in the body of the pancreas. Laboratory analysis showed elevated levels of both vasoactive intestinal polypeptide (VIP; 153 pmol/l) and pancreatic polypeptide (161 pmol/l). In view of the patient's age, physical condition, and tumour size, surgical resection was not performed. The patient was treated with a long-acting octreotide, after which her symptoms diminished. After 24 months of follow-up, the patient remained in good physical condition without any further serious gastrointestinal symptoms. The VIPoma syndrome is caused by a neuroendocrine tumour, usually located in the pancreas, which secretes VIP, causing severe diarrhoea, dehydration and hypokalaemia. Treatment options include resection of the tumour, chemotherapy or the reduction of symptoms with somatostatin analogues. We provide an overview of the incidence, pathophysiology, diagnosis, treatment strategies, and prognosis of this rare syndrome.

[Surgical treatment of gastric, enteric, and pancreatic endocrine tumors Part 1. Treatment of primary endocrine tumors]

Endocrine tumors (ET) of the digestive tract (formerly called neuroendocrine tumors) are rare. They are classified into two principal types: gastrointestinal ET's (formerly called carcinoid tumors) which are the most common, and pancreaticoduodenal ET's. Functioning ET's secrete polypeptide hormones which cause characteristic hormonal syndromes. The management of ET is multidisciplinary. Poorly-differentiated ET's have a poor prognosis and are treated by chemotherapy. Surgical excision is the only curative treatment of well-differentiated ET's. The surgical goals are to: 1. prolong survival by resecting the primary tumor and any nodal or hepatic metastases, 2. control the symptoms related to hormonal secretion, 3. prevent or treat local complications. The most common sites of gastrointestinal ET's ( carcinoids) are the appendix and the rectum; these are often small (<1 cm), benign, and discovered fortuitously at the time of appendectomy or colonoscopic removal. Ileal ET's, even if small, are malignant, frequently multiple, and complicated in 30-50% of cases by bowel obstruction, mesenteric invasion, or bleeding. The carcinoid syndrome (consisting of abdominal pain, flushing, diarrhea, hypertension, bronchospasm, and right sided cardiac vegetations) is caused by the hypersecretion of serotonin into the systemic circulation; it occurs in 10% of cases and is usually associated with hepatic metastases. More than half of the cases of pancreatic ET are non-functional. They are usually malignant and of advanced stage at diagnosis presenting as a palpable or obstructing mass or as liver metastases. Insulinoma and gastrinoma (cause of the Zollinger-Ellison syndrome) are the most common functional ET's. 80% are sporadic; in these cases, tumor size, location, and malignant potential determine the type of resection which may vary from a simple enucleation to a formal pancreatectomy. In 10-20% of cases, pancreaticoduodenal ET presents in the setting of multiple endocrine neoplasia (NEM type I), an autosomal-dominant genetic disease with multifocal endocrine involvement of the pituitary, parathyroid, pancreas, and adrenal glands. For insulinoma with NEM-I, enucleation of lesions in the pancreatic head plus a caudal pancreatectomy is the most appropriate procedure. For gastrinoma with NEM-I, the benefit of surgical resection for tumors less than 2-3 cm in size is not clear. The lesions are frequently small, multiple, and widespread and recurrence is frequent after excision. The long-term prognosis is nevertheless fairly good. But the eventual development of liver metastases which are the most common cause of mortality still argues for an aggressive surgical approach in the early stages of the disease.

Enteroendocrine tumors other than carcinoid: a review of clinically significant advances

Only relatively recently has there been an increased clinical recognition and characterization of the heterogeneous group of rare gastroenteropancreatic neuroendocrine neoplasms. Most have endocrine function and exhibit varying degrees of malignancy. This review summarizes the derivation of these tumors and the advances in their diagnosis and treatment over the past decade and a half. They are varied in their biological behavior and clinical courses and, depending on their cell type, can produce different hormones causing distinct clinical endocrine syndromes (insulinoma [hypoglycemia], gastrinoma [Zollinger-Ellison syndrome (ZES)], vasoactive intestinal peptideoma [VIPoma], watery diarrhea, hypokalemia-achlorhydria [WDHA], glucagonoma [glucagonoma syndrome], and so forth). In addition to surgery for cure or palliation (by excision and a variety of other cytoreductive techniques), they each are treated with anti-hormonal agents or drugs targeted to each tumor's specific product or its effects. The majority have benefited from the gut hormone-inhibiting action of somatostatin analogs. Because of their usual slow rate of growth it is recommended that, even when they are advanced and incurable, unlike in patients with common and more malignant cancers, patients with neuroendocrine tumors often can be palliated and appear to survive longer when managed with an active approach using sequential multimodality treatment. Advances in these various therapies are reviewed and the beneficial emergence of global self-help patient support groups is noted.

Surgical treatment of non-functioning pancreatic islet cell tumors

Pancreatic endocrine tumors (PETs) are rare neoplasms originating from the amine precursor uptake and decarboxylation (APUD) stem cells. Although the majority of PETs are sporadic, they frequently occur in familial syndromes. PETs may cause a variety of functional syndromes or symptoms of local progression if they are non-functional. General neuroendocrine tumor markers are highly sensitive in the diagnostic assessment of a PET. Imaging studies for tumor localization and staging include computer tomography (CT) scan, magnetic resonance imaging (MRI), In(111)-octreotide scan, MIBG, and endoscopic ultrasonography (EUS). Treatment of PETs often requires a multi-modality approach; however, surgical resection remains the only curative therapy for localized (non-metastatic) disease. Treatment of metastatic disease includes biologic agents, cytotoxic chemotherapy, and liver-directed therapies.

Fluorouracil, doxorubicin, and streptozocin in the treatment of patients with locally advanced and metastatic pancreatic endocrine carcinomas

PURPOSE

The role of systemic chemotherapy in the management of pancreatic endocrine carcinoma (islet cell carcinoma; PEC) is an area of considerable controversy. Response rates ranging from 6% to 69% have been reported for streptozocin-based chemotherapy. We retrospectively studied 84 patients with locally advanced or metastatic PEC who had been treated with fluorouracil, doxorubicin, and streptozocin (FAS) to determine the objective response rate, duration of progression-free survival (PFS), and duration of overall survival (OS).

PATIENTS AND METHODS

Eligible patients had histologic or cytologic confirmation of their tumor and measurable disease on computed tomography or magnetic resonance imaging scans. Response to treatment was evaluated in this study using the new international criteria proposed by the Response Evaluation Criteria in Solid Tumors Committee.

RESULTS

Sixty-one of the patients were male and 23 were female, with a median age of 54 years (range, 24 to 78 years). The response rate (RR) to FAS was 39%, with a median response duration of 9.3 months. The 2-year PFS rate was 41%, and the 2-year OS rate was 74%. The extent of liver metastatic disease correlated with a worse PFS (P = .01 by log-rank test) and a worse OS (P < .0001 by log-rank test). Analyses showed that metastatic replacement of more than 75% of the liver and prior chemotherapy were independently associated with inferior PFS.

CONCLUSION

Patients with locally advanced or metastatic PEC who are treated with FAS may have a reasonable RR, and responders may experience longer PFS and OS. The volume of metastases in the liver is the most important predictor of outcome.

Insulinoma

Insulinomas are the most common islet cell tumors and are located almost exclusively in the pancreas. Most of these tumors are sporadic, but they may also be associated with the multiple endocrine neoplasia type I syndrome. More than 90% of insulinomas are benign. Preoperative radiographic localization may prove difficult. Intraoperative palpation and ultrasound remain the gold standard for detection and appropriately planned resection. Although many options are available to treat the patient with malignant and metastatic disease, the mainstay of treatment remains surgery. Laparoscopic ultrasound and enucleation/resection may be increasingly used in the management of patients with insulinoma.

Sandostatin LAR (long-acting octreotide acetate) for malignant carcinoid syndrome: a 3-year experience

BACKGROUND

Somatostatin analogues are the best therapy for controlling the symptoms of malignant carcinoid syndrome. Octreotide acetate given as subcutaneous injection up to three times daily, intramuscular Lanreotide injection given once per 1-2 weeks and monthly intramuscular Sandostatin LAR have demonstrated similar efficacy in short-term studies.

AIM

To assess the long-term effect of Sandostatin LAR on the management of patients with malignant carcinoid syndrome.

METHODS

This was a 3-year retrospective study. Twenty-seven patients were assessed with a median follow-up of 23 months. Thirteen patients were switched from subcutaneous octreotide and 14 patients were octreotide naive. All patients showed avid uptake on indium-111 octreotide imaging.

RESULTS

Ten of the 13 patients previously on subcutaneous octreotide and 13 of the 14 patients who were octreotide naive had good symptom control on Sandostatin LAR. Over the period of follow-up, many patients showed progression of their tumour and required additional therapies. Patients expressed a preference for monthly intramuscular Sandostatin LAR as opposed to daily subcutaneous injections of octreotide. Although Sandostatin LAR was difficult to administer in certain instances, overall it was well tolerated.

CONCLUSIONS

Sandostatin LAR provides good long-term symptomatic control in patients with malignant carcinoid syndrome; it is well tolerated and patients expressed improved satisfaction in their management.

Hepatic artery embolization for control of symptoms, octreotide requirements, and tumor progression in metastatic carcinoid tumors

Hepatic artery embolization (HAE) has been utilized for treatment of advanced hepatic carcinoid metastases, with promising symptom palliation and tumor control. Our institution employs transcatheter HAE using Lipiodol/Gelfoam for treatment of carcinoid hepatic metastases, and this report presents our experience with twenty-four patients, examining symptom control, quality-of-life, octreotide dependence, and tumor progression. Twenty-four (11 male, 13 female, mean age = 59.4 +/- 2.5 yr) patients with carcinoid and unresectable hepatic metastases, confirmed by urinary 5-hydroxyindole acetic acid (5-HIAA) measurement and biopsy, were treated with Lipiodol/Gelfoam HAE from 1993-2001. Median follow-up was 35.0 months. Before HAE, 14 patients (58.3%) had malignant carcinoid syndrome, with symptoms quantified using our previously reported Carcinoid Symptom Severity Score, and 13 patients (54.2%) required octreotide for symptom palliation. Following treatment, symptom severity, octreotide dose, and tumor response were measured. Asymptomatic patients did not develop symptoms or require following treatment. Hepatic metastases remained stable (n = 4) or decreased (n = 19) in 23 patients (95.8%). Mean pretreatment Symptom Severity Scores (3.8 +/- 0.2), decreased to 1.4 +/- 0.1 post-treatment (P < 0.00001), with 64.3% of patients becoming asymptomatic. Mean pretreatment octreotide dosages (679.6 +/- 73.0 microg/d), decreased to 262.9 +/- 92.7 microg/d (P = 0.0024) post-treatment, with 46.2% of patients discontinuing octreotide. There were no treatment-related serious complications or deaths. This study demonstrates that Lipiodol/Gelfoam HAE produces excellent control of malignant carcinoid syndrome, allowing patients to decrease or eliminate use of octreotide, while controlling hepatic tumor burden.

The value of radiolabelled MIBG and octreotide in the diagnosis and management of neuroendocrine tumours

Neuroendocrine tumours have a particular tendency to express functional receptors and/or uptake mechanisms. Radionuclides, such as 123I-MIBG, which is taken up by a specific uptake mechanism, and 111In-pentetreotide, which binds to somatostatin receptors, present an imaging modality based on these physiological characteristics rather on purely anatomical alterations. They have been successfully utilised for both the diagnosis and staging of neuroendocrine tumours, as they can identify lesions beyond the diagnostic sensitivity of conventional imaging modalities. Scintigraphy with 111In-pentetreotide is in general more sensitive but scintigraphy with 123I-MIBG may occasionally demonstrate lesions not evident with 111In-pentetreotide. Although both are effective in identifying hepatic metastases there may be quantitative and qualitative differences in the pattern of uptake. 131I-MIBG therapy, based on a positive 123I-MIBG scan, produces symptomatic and hormonal improvement and moderate tumour regression/stabilisation in many patients with metastatic neuroendocrine tumours with minimal adverse effects. It may be a valuable alternative or additional therapeutic option to the currently available conventional treatment modalities. Although experience with 90Y-DOTA-D-Phe1-Tyr3-octreotide therapy is still limited, preliminary studies have demonstrated useful activity in tumours with positive 111In-pentetreotide scans, and yet other radionuclide analogues may become available. However, treatment with the combination of both radionuclides is another therapeutic possibility.

The clinical management of neuroendocrine tumors with long-acting repeatable (LAR) octreotide: comparison with standard subcutaneous octreotide therapy

Neuroendocrine tumors are rare, occurring in less than 1% of the population. They are divided clinically into functionally active or non-active tumors. Functionally active tumors produce a variety of substances (mainly peptides or serotonin) that are responsible for symptoms and sometimes can lead to the death of the patient independently from tumor proliferation. The most important compounds that can control symptoms in these patients are somatostatin analogs. Native somatostatin is not suitable for long-term clinical application due to its short half-life. Therefore, synthetic drugs were developed with improved pharmacokinetic characteristics. The best-characterized analog, octreotide, has been successfully applied to patients with functioning tumors. Octreotide can ameliorate symptoms in 30%-70% of the patients, mainly through a direct inhibitory effect on hormone production from the tumors. There is little or no effect on tumor growth during octreotide therapy; clinical responses were recorded in only 10%-30% of the patients. Recently, significant improvement in the management of the disease has been demonstrated with long-acting repeatable (LAR) octreotide. This new formulation requires only one monthly intramuscolar injection, and shows better acceptability and patient compliance to therapy. Data available to date show superimposable results of both standard octreotide and LAR octreotide in controlling symptoms, lowering hormone and tumor marker levels, and in reducing tumor growth. The availability of long-acting molecules have permitted the exploration of high-dose therapy in increasing tumor shrinkage and prolonging survival. Although there is a clear dose-response trend, the published data are not conclusive and further investigations are needed. The possible lack of cross-resistance between LAR octreotide and a different analog, Lanreotide, is a very stimulating finding and this might lead to the development of new therapeutical strategies in the management of neuroendocrine tumors.

Treatment of metastatic carcinoid tumours, phaeochromocytoma, paraganglioma and medullary carcinoma of the thyroid with (131)I-meta-iodobenzylguanidine [(131)I-mIBG]

OBJECTIVE

Meta-iodo-benzyl-guanidine labelled with 131-iodine [(131)I-mIBG] has been used extensively for imaging tumours originating from the neural crest but experience with its therapeutic use is limited, particularly for non-catecholamine secreting tumours. In order to assess the therapeutic response and potential adverse effects of the therapeutic administration of (131)I-mIBG, we have reviewed all patients who had received this form of treatment in our department.

DESIGN

Retrospective analysis of the case notes of patients with neuroendocrine tumours who received treatment with (131)I-mIBG and were followed-up according to a defined protocol in a given time frame.

PATIENTS

Thirty-seven patients (18 with metastatic carcinoid tumours, 8 metastatic phaeochromocytoma, 7 metastatic paraganglioma and 4 metastatic medullary carcinoma of the thyroid) treated with (131)I-mIBG over a 15-year period were included in this analysis.

MEASUREMENTS

The symptomatic, hormonal and tumoural responses before and after (131)I-mIBG therapy over a median follow-up duration of 32 months (range 5-180 months) were recorded. Of the 37 patients (22 males; median age 51 years, range 18-81 years), 15 were treated with (131)I-mIBG alone whereas the other 22 received additional therapy.

RESULTS

A total of 116 therapeutic (131)I-mIBG doses were administered [mean cumulative dose 592 mCi (21.9 GBq); range 200-1592 mCi (7.4-58.9 GBq)]. None of the patients showed a complete tumour response. However, 82% of patients treated with (131)I-mIBG alone and 84% who received additional therapy showed stable disease over the period of follow-up. Overall survival during the period of the study was 71%. The overall 5-year survival rate was 85% (95% confidence interval, 72-99%) for all patients and 78% (95% confidence interval, 55-100%) for the carcinoid group alone, according to Kaplan-Meier analysis. Symptomatic control was achieved in all the patients treated with (131)I-mIBG alone, and in 72% of those receiving additional therapy. Hormonal control was noted in 50% and 57% of patients, respectively. (131)I-mIBG therapy was safe and well tolerated. Serious side-effects necessitating the termination of (131)I-mIBG therapy were seen in only 2 of our patients.

CONCLUSIONS

(131)I-mIBG therapy produces symptomatic and hormonal improvement and moderate tumour regression/stabilization in patients with metastatic neuroendocrine tumours with minimal adverse effects. It may be a valuable alternative or additional therapeutic option to the currently available conventional treatment modalities.

Surgery as primary treatment in patients with liver metastases from carcinoid tumors: a retrospective, unicentric study over 13 years

BACKGROUND

The heterogeneous nature of carcinoid tumors makes it difficult to develop a standardized treatment strategy for the primary tumor itself and for probable liver metastases. However, prolongation of the 5-year survival rate (5-ysr) and amelioration of the incapacitating symptoms after resection of the primary tumor and its metastases demonstrate that surgical intervention must be the treatment of choice in these tumors.

METHODS

The data of 31 patients (17 patients with midgut carcinoids, 10 patients with an endocrine carcinoma (carcinoid) of the pancreas, and 4 patients with carcinoids of the lung) who underwent liver operation for metastatic carcinoid tumors between 1983 and 1996 were analyzed, with special regard to factors influencing postoperative survival.

RESULTS

Ten patients underwent curative resection (5-ysr, 86%), and palliative operations were performed in 21 patients (5-ysr, 26%). The overall 5-ysr was 47%, with a mean postoperative follow-up of 3.5 years (range, 4 months to 10.8 years). Postoperative morbidity rate was 13%. Size of liver metastases, radicality of the operation and localization of the primary tumor were factors influencing postoperative survival.

CONCLUSIONS

Surgery for metastatic carcinoid tumors may be curative or palliative, with a potential for cure in some cases and prolongation of survival and amelioration of symptoms in the majority of patients.

Current imaging and possible therapeutic management of glucagonoma tumors: a case report

Glucagonomas, like other neuroendocrine tumors, express somatostatin receptors in more than 80% of cases. Unfortunately, because of the rarity of these tumors, the sensitivity and specificity of somatostatin analog (octreotide) imaging have not been established. Nonetheless, there have been limited reports in the literature supporting the use of indium In-111 DTPA N-terminal D-phenylalanine (D-PHE1) octreotide for glucagonoma imaging and may be most beneficial as an adjuvant to conventional imaging for tumor staging and therapeutic decision making. Current therapeutic applications of octreotide focus on stabilization of disease in tumors expressing somatostatin receptors, and tumor destruction, using beta-emitting isotopes. In this report, imaging of a glucagonoma with In-111 DTPA-D-PHE1 octreotide scintigraphy is described in a 51-year-old woman examined for a large palpable abdominal mass.

Multimodality treatment for gastric carcinoid tumor with liver metastases

Carcinoid tumors are the most common neuroendocrine tumors in the gastrointestinal tract, and between 10% and 30% of these tumors are gastric in origin. Three types of gastric carcinoid tumors are recognized: type I, associated with chronic atrophic gastritis type A; type II, associated with multiple endocrine neoplasia; and type III, sporadic and the most malignant. We present a patient with an aggressive, sporadic-type gastric carcinoid that metastasized to the liver. Her symptomatic treatment included the somatostatin analog octreotide. Octreotide scintigraphy demonstrated that this tumor avidly bound the peptide. The patient's gastric carcinoid (assessed by endoscopy and endoscopic ultrasound) regressed and she underwent hepatic artery embolization for her liver metastases. After initial partial CT resolution the tumor grew, compressing the inferior vena cava. The patient underwent orthotopic liver transplant with excellent recovery, although she was subsequently found to have two small lung metastases. She has responded well to adjuvant Indium-111 octreotide receptor targeted therapy. This case highlights the therapeutic options for metastatic neuroendocrine tumors, including liver transplantation and adjuvant receptor targeted therapy.

Carcinoid tumour

Carcinoid tumours are often indolent asymptomatic tumours. However, a small but significant proportion are malignant and difficult to manage. Multiple endocrine neoplasia type 1 (MEN-1) may be associated with carcinoid tumours and should therefore be considered in the investigation of these patients. This review puts into context the use of newer imaging modalities, including octreotide scintigraphy. The therapeutic treatment options are discussed, including the use of octreotide, the role of receptor-targeted therapy, hepatic-artery embolisation, and the arguments against chemotherapy. We review the need for careful patient selection when considering curative and palliative surgery, including liver transplantation. We conclude that there are now better diagnostic tools and therapeutic options available for those patients with malignant carcinoid tumours, and that these patients are best managed by a multidisciplinary approach. Earlier detection and treatment of these tumours should lead to improved quality of life and survival, which, ideally, should be assessed in formal trials.

The octreotide suppression test and [111In-DTPA-D-Phe1]-octreotide scintigraphy in neuroendocrine tumours correlate with responsiveness to somatostatin analogue treatment

OBJECTIVE

The somatostatin analogue octreotide (Sandostatin, Novartis, Basie) significantly improves the syndromes suffered by most patients with neuroendocrine tumours (NETs). The use of [111In-DTPA-D-Phe1]-octreotide scintigraphy ([111In]-pentetreotide) to predict the response to octreotide treatment has been described. Short-term hormone inhibition by a single injection of octreotide has also been reported. This study aimed to compare the effects of the suppression test with the response to long-term somatostatin analogue treatment, and to seek a correlation between the short-term suppression test, [11In]-pentetreotide observations and long-term somatostatin analogue treatment.

DESIGN AND MEASUREMENTS

Short octreotide suppression test and octreotide scintigraphy. Blood samples were collected before (0900, 0930 h), at (1000 h), and after (1030, 1100, 1200, 1300 h) the injection of 50 micrograms octreotide subcutaneously. Plasma hormones relevant to the syndrome were analysed by radioimmunoassay. The short suppression effects, the [111In]-pentetreotide observations and the response to long-term treatment with somatostatin analogue were evaluated and compared.

PATIENTS

Twenty-six patients with metastatic NETs were evaluated, including 14 carcinoid tumours, 10 pancreatic endocrine tumours and 2 medullary carcinomas of thyroid (MCTs). Twelve patients had received octreotide treatment before the study, another 4 patients were treated subsequently with somatostatin analogue.

RESULTS

During the short suppression test, hormones relevant to the syndromes were suppressed in 24 patients (those with carcinoids and pancreatic endocrine tumours). There was no suppression in the 2 patients with MCT. [111In]-pentetreotide observations closely correlated with the short suppression response to octreotide. Fourteen patients were treated with somatostatin analogue, and responded clinically; they had a positive short inhibition test and positive tumour uptake. Two patients with MCT did not respond to the treatment and had a negative suppression test and a negative [111In]-pentetreotide.

CONCLUSION

Our results suggest that a consistent relationship exists between the short suppression test and the response to somatostatin analogue treatment in the majority of the patients with neuroendocrine tumours. The octreotide suppression test and octreotide scintigraphy together will be helpful in selecting appropriate patients for clinical treatment with somatostatin analogues.

Vasoactive intestinal polypeptide-secreting tumours: biology and therapy

VIP-secreting tumours are rare, but they produce a dramatic clinical picture, the most prominent feature being profuse, watery diarrhoea and hypokalaemia. VIPomas are malignant and require sophisticated diagnostic and localization techniques in order to identify their presence. Delays in diagnosis are the rule rather than the exception. Improvements in the diagnosis of VIPomas appear to result in an increase in resectability rates. A definitive diagnosis is aided by the determination of plasma VIP concentrations through the use of sensitive radioimmunoassays. With heightened awareness of this syndrome, increasing numbers of patients can be identified and more effective treatments developed for the refractory and recurrent tumours.

Gastrointestinal endocrine tumours. Gastrinoma

Since the description of the Zollinger-Ellison syndrome in two patients in 1955, there have been significant advances in the understanding of its pathogenesis, natural history, relationship to multiple endocrine neoplasia type 1, diagnosis, methods of tumour localization and management. The main focus in treatment is now shifting from management of the gastric acid hypersecretory state which can now be controlled medically in almost every patient, to the management of the gastrinoma. Recent studies are beginning to provide insights into the natural history of gastrinomas, factors that are associated with invasiveness in some gastrinomas, defining the role of surgery in managing patients with different disease extents, or with MEN 1 and being able to provide insights into molecular abnormalities that may be important in their pathogenesis. In this article each of these advances is briefly reviewed with emphasis primarily on recent advances.

Surgical management of gastrointestinal endocrine tumours

The surgical management of gastrointestinal endocrine tumours must involve a multidisciplinary approach. The importance of accurate diagnosis, rendering the patient safe, and, in our opinion, localizing the tumour(s) before embarking on surgery cannot be overemphasized. Surgery is the only available treatment for cure. Occult primary tumours are now rarely a problem with novel imaging techniques, which can also improve detection and hence clearance of local spread. Surgical management in extensive metastatic or multicentric disease is less rigidly defined, and is dependent on the endocrine syndrome. A better understanding of tumour pathology, for example in MEN 1, has not always simplified matters. An appreciation of the benefit of chemotherapy, use of somatostatin analogues and hepatic artery embolization are vital to target appropriate palliative surgery. Hepatic transplantation may have an increasing role in the future. Surgical strategies must adapt to new medical treatments. If therapeutically relevant, advances in tumour biology (for example somatostatin receptor subtypes and growth factors) will influence surgical strategies in the future.

Somatostatin receptor regulation of gastric enterochromaffin-like cell transformation to gastric carcinoid

BACKGROUND

Although somatostatin is recognized as an inhibitor of neuroendocrine cell secretion, its effect on cell proliferation has not been well defined. Generation of low acid and hypergastrinemia through irreversible H2-receptor blockade (loxtidine) in the African rodent mastomys results in gastric carcinoids (ECLomas) within 4 months. This study was undertaken to evaluate and characterize the precise somatostatin receptor (SSTR) subtype on the mastomys enterochromaffin-like (ECL) cell and to define its role in the regulation of ECL cell secretion and proliferation.

METHODS

A pure preparation (approximately 90%) of ECL cells was derived by a combination of pronase digestion and density gradient separation. We assessed the effect of somatostatin (10(-15) to 10(-7) mol/L) on gastrin-stimulated ECL cell histamine secretion and DNA synthesis (bromodeoxyuridine uptake). SSTR2 subtype was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) using gene specific primers and mRNA isolated from normal and hypergastrinemia-induced ECLoma. The polymerase chain reaction product was confirmed by Southern analysis, subcloned, and sequenced.

RESULTS

Somatostatin inhibited both gastrin-stimulated histamine secretion (IC50, 5 x 10(-13) mol/L) and DNA synthesis (IC50, 10(-10) mol/L). SSTR2 was identified in the mastomys' brain, and both normal and tumor ECL cells and comparison of the brain and ECL cell SSTR2 nucleotide sequences revealed homology of 99%.

CONCLUSIONS

The SSTR2 is expressed by the mastomys' ECL cell and ECLoma. Receptor activation inhibits both ECL cell secretory and proliferative functions.

[Therapy of carcinoids of the stomach]

Carcinoids of the stomach are rare but have gained importance since the introduction of acid secretion inhibitors. The most important type is the tumor occurring in patients with chronic atrophic gastritis with and without pernicious anemia. The tumors are benign and can be treated by local endoscopic or surgical methods. Antrectomy reduces hypergastrinemia and may cause regression of the tumor. Sporadic carcinoids of the gastric antrum are malignant, however, and require radical surgical treatment.