Streptozocin alone compared with streptozocin plus fluorouracil in the treatment of advanced islet-cell carcinoma

Endocrine pancreatic tumors: diagnosis and treatment

Endocrine pancreatic tumors (EPTs) are uncommon, having an incidence of one per 100,000 people. They may appear as sporadic tumors or be associated with hereditary syndromes. EPTs are categorized as functioning or nonfunctioning tumors, based on the presence or absence of clinical syndromes. Among the former, insulinomas and gastrinomas are the most common. For the histopathological investigation of EPTs, chromogranin A and synaptophysin immunostainings are recommended. Measurement of circulating chromogranin A is also the cornerstone for the biochemical diagnosis of these tumors. Furthermore, specific hormones produced and released by the neoplastic cells can be identified by immunostaining and used for biochemical evaluation. To locate EPTs, both noninvasive (ultrasonography, computerized tomography, MRI and radionuclear imaging) and invasive techniques (arterial stimulation with venous sampling) can be used. Debulking procedures (surgery, radiofrequency ablation, embolization/chemoembolization and liver transplantation) and/or medical treatment (chemotherapy, biotherapy and peptide receptor radionuclide therapy) are the options available for the treatment of EPTs. Understanding the molecular events underlying the pathobiology of EPTs will aid the development of more accurate diagnostic/prognostic markers and give guidance for improved therapeutic modalities.

Medical management of pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNET) are rare malignancies frequently diagnosed at a late stage, with symptoms related to bulky disease. Hormonal secretion, when responsible for symptoms, permits, on the other hand, early diagnosis of the disease. Surgery remains the cornerstone of therapeutic management. However, due to advanced disease, many patients are not candidates for aggressive surgical therapy. Tumor growth control and symptom management are thus achieved through medical approaches, including somatostatin (SST) analogs, chemotherapy, interferon, and more recently, targeted therapy. The purpose of this review is to collect, examine, and analyze data available in the literature regarding contemporary therapeutic management of PNET, with emphasis on medical approaches. It also offers perspectives on the future of molecular targeted therapies in these neoplasms. However, we point out that much of the literature published to date includes noncomparative studies (mainly phase II studies), leading to thorny interpretation of the results.

METHODS

A systematic search of all the literature in English regarding PNET was performed, based on a MEDLINE search (Pubmed) carried out from January 1970 to May 2005.

RESULTS

Approximately 40 trials, including over 1,000 patients, have been retrieved from our MEDLINE search. SST analogs and interferon therapies do allow control over hormone secretion and subsequent symptoms in the majority of treated subjects, but offer a poor tumor growth control rate. Chemotherapies, although more efficient in reducing tumor burden, are often toxic. New approaches such as immunotherapy and targeted therapies are still under investigation.

CONCLUSIONS

Whether alone or in combination with surgery, conventional medical therapies represent a crucial aspect of PNET management. Hopefully, in the near future, a new era of antitumoral agents, such as targeted therapies, will strengthen our therapeutic arsenal, either alone or combined with other therapies.

[Endocrine tumors of the pancreas (EPTs) in multiple endocrine neoplasia (MEN1): up-date on prognostic factors, diagnostic procedures and treatment]

Endocrine pancreatic tumors (EPTs) are uncommon tumors, representing 1-2% of all pancreatic neoplasms. They are categorized on the basis of their clinical features into functioning and non-functioning tumors. EPTs may be part of the multiple endocrine neoplasia type 1 (MEN 1), an autosomal dominant syndrome due to inactivating germline mutation of the menin gene. Somatic mutations of menin are present in about 20% of sporadic neoplasms, particularly gastrinomas and insulinomas. 30-75% of patients with MEN1 have EPTs. The most prevalent are the gastrinomas (20-60%), then the insulinomas (5-10%), the glucagonamas and VIPomas (6-10%), whereas the nonfunctioning EPTs are present in 20-40% of patients. The most important biochemical screening marker for EPTs is chromogranin A, as it increases in 50-80% of patients. The most important negative prognostic factors are the presence of metastases, the gross invasion of adjacent organs, the angioinvasion, the perineural invasion and an immunopositivity for Ki-67 > 2%. Among the different imaging techniques, echoendoscopy, computed tomography (CT) and magnetic resonance imaging (MRI) are indicated for the detection of the primary tumor, but (III)In-octreotide scintigraphy has the highest sensitivity for detecting metastases. The choice of treatment is still debated and is different when the tumor occurs as a part of the MEN syndrome. The surgical treatment is the first choice for insulinomas and is more controversial for gastrinomas. The medical treatment includes somatostatin analogues (SA), chemotherapy and interferon-alpha (IFN-alpha). SA seem to improve the symptoms and have an antiproliferative effect, the most striking effect being seen in patients with VIPomas. Chemotherapy, which is generally proposed as a combination of streptozotocin (STZ) and 5-fluorouracil (5-FU) or doxorubicin, is indicated when the tumors tend to grow. Interferon-alpha (IFN-alpha) stimulates the immune system, blocks the tumor cells in the G1/S-phase of the cell cycle, inhibits protein and hormone synthesis and inhibits angionenesis. Treatment with IFN has been shown to produce symptomatic response in 40-60% of patients, a biochemical response in 30-60% and tumor shrinkage in 10-15%.

Peptide Receptor Radionuclide Therapy with radiolabelled somatostatin analogues in patients with somatostatin receptor positive tumours

Peptide Receptor Radionuclide Therapy (PRRT) with radiolabelled somatostatin analogues is a promising treatment option for patients with inoperable or metastasised neuroendocrine tumours. Symptomatic improvement may occur with all of the various (111)In, (90)Y, or (177)Lu-labelled somatostatin analogues that have been used. Since tumour size reduction was seldom achieved with (111)Indium labelled somatostatin analogues, radiolabelled somatostatin analogues with beta-emitting isotopes like (90)Y and (177)Lu were developed. Reported anti-tumour effects of [(90)Y-DOTA(0),Tyr(3)]octreotide vary considerably between various studies: Tumour regression of 50% or more was achieved in 9 to 33% (mean 22%). With [(177)Lu-DOTA(0),Tyr(3)]octreotate treatments, tumour regression of 50% or more was achieved in 28% of patients and tumour regression of 25 to 50% in 19% of patients, stable disease was demonstrated in 35% and progressive disease in 18%. Predictive factors for tumour remission were high tumour uptake on somatostatin receptor scintigraphy and limited amount of liver metastases. The side-effects of PRRT are few and mostly mild, certainly when using renal protective agents: Serious side-effects like myelodysplastic syndrome or renal failure are rare. The median duration of the therapy response for [(90)Y-DOTA(0),Tyr(3)]octreotide and [(177)Lu-DOTA(0),Tyr(3)]octreotate is 30 months and more than 36 months respectively. Lastly, quality of life improves significantly after treatment with [(177)Lu-DOTA(0),Tyr(3)]octreotate. These data compare favourably with the limited number of alternative treatment approaches, like chemotherapy. If more widespread use of PRRT is possible, such therapy might become the therapy of first choice in patients with metastasised or inoperable gastroenteropancreatic neuroendocrine tumours. Also the role in somatostatin receptor expressing non-GEP tumours, like metastasised paraganglioma/pheochromocytoma and non-radioiodine-avid differentiated thyroid carcinoma might become more important.

Treatment of patients who have endocrine gastroenteropancreatic tumors with radiolabeled somatostatin analogues

Treatment with radiolabeled somatostatin analogs is a promising new tool in the management of patients who have inoperable or metastasized endocrine tumors. Symptomatic improvement may occur with all (111)In-, (90)Y-, or (177)Lu-labeled somatostatin analogs that have been used for peptide receptor radionuclide therapy. The results that were obtained with [(90)Y-DOTA degrees ,Tyr(3)]octreotide and [(177)Lu-DOTA degrees ,Tyr(3)]octreotate are encouraging in tumor regression. Also, if kidney-protective agents are used, the side effects of this therapy are few and mild. These data compare favorably with the limited number of alternative treatment approaches.

Treatment of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are rare; thus, individual experience with the diagnosis and treatment of these tumors is mostly low, except in specialized centers. For histological diagnosis, standards have been described recently. Pathological classification and clinical staging influence diagnostic and therapeutic decisions. This chapter aims at demonstrating the importance of pathological and clinical classification of neuroendocrine tumors on therapeutic decisions, indicating the appropriate therapy for different stages of the disease. Surgical therapy will be discussed shortly, including palliative surgical strategies. However, the focus of the manuscript is medical therapy. Biotherapy, its effects, and remaining uncertainties are presented as well as different chemotherapeutic schemes. Finally, new options of palliative medical therapies like kinase inhibitors and anti-angiogenetic drugs will be discussed.

A review of the current clinical trials for gastroenteropancreatic neuroendocrine tumours

Neuroendocrine tumours of the gastroenteropancreatic axis include carcinoid tumours and islet cell tumours of the pancreas (pancreatic endocrine tumours). Standard medical therapies prescribed for these malignancies include long-acting somatostatin analogues (octreotide and lanreotide) for the palliation of hormonal syndromes; cytotoxic agents (streptozocin, dacarbazine, adriamycin and 5-fluorouracil), which are primarily for the management of advanced islet cell tumours; and hepatic artery embolisation or chemoembolisation for the treatment of liver metastases. Clinical research promises to expand this therapeutic armamentarium. Most of the experimental treatments that are being evaluated in human clinical trials fall into the following categories: angiogenesis inhibitors, novel somatostatin analogues, radiolabelled somatostatin analogues, mTOR inhibitors and novel cytotoxic agents. This review summarises the present scope of clinical research in this field.

Cytotoxic treatment including embolization/chemoembolization for neuroendocrine tumours

In patients with advanced neuroendocrine tumours, surgery is curative in only a minority of cases, whilst the anti-tumour effect of somatostatin analogues, despite efficient symptom control, is limited. Systemic chemotherapy has been proved to be effective only in certain tumour types. Although metastatic midgut carcinoids and well-differentiated gastrointestinal carcinoids are relatively insensitive to chemotherapy, pancreatic neuroendocrine tumours show a response rate of around 40% to streptozotocin-based combinations, particularly with fluorouracil and doxorubicin. Poorly differentiated tumours respond even better, especially to a combination of cisplatin and etoposide. In patients with predominant liver disease, ischaemia of tumour lesions induced by vascular occlusion by particle embolization or chemoembolization may be considered. This may have clinical and biochemical responses up to 80%, and objective responses up to 60%, in disease which is progressive despite previous treatments. Potential adverse effects and short duration of response should be taken into account.

Effective treatment of locally advanced endocrine tumors of the pancreas with chemoradiotherapy

BACKGROUND/AIMS

The use of chemoradiation in the management of locally advanced pancreatic endocrine tumors has not been reported in the medical literature. Patients with unresectable tumors are often included in trials of systemic chemotherapy, and use of external beam radiation has been only described in few case reports. Given the sensitivity of pancreatic endocrine tumors to cytotoxic agents including streptozocin, doxorubicin and 5-FU, we have hypothesized that the combination of concurrent and sequential chemotherapy and radiation will yield higher response rates than acheivable with chemotherapy alone.

METHODS

Six patients with locally advanced pancreatic endocrine tumors were treated with a protocol consisting of radiation concurrent with infusional 5-FU (or capecitabine) along with induction and consolidation chemotherapy (streptozocin and doxorubicin). We retrospectively determined the objective radiographic response rate.

RESULTS

The objective response rate was 80%. With a median follow-up of 29 months, all six patients in the study have had continued reduction in tumor size from the time of the first posttreatment scan to the most recent scan. None of the patients have experienced local or metastatic disease progression. Treatment was well tolerated with minimal toxicity.

CONCLUSION

The combination of concurrent and sequential chemoradiotherapy appears to be a highly effective treatment for locally advanced pancreatic endocrine tumors.

Arterial phase enhancement and body mass index are predictors of response to chemoembolisation for liver metastases of endocrine tumours

Transcatheter arterial chemoembolisation (TACE) has been reported to be an efficient treatment of liver metastases of endocrine tumours in short series of patients. However, several factors seem to affect its results. The aim of this work is to identify predictors of response to TACE for liver metastases of endocrine tumours. A total of 163 TACE procedures were performed in 67 patients between 1994 and 2004. Forty-four patients were treated with streptozotocin and 23 with doxorubicin. Primary tumour was located in the pancreas for 19 patients, and had been removed in 43. Thirty-eight tumours were functioning. Response rate was 37% (confidence interval [CI] 95%: 28–49%). Median time to progression (TTP) was 14.5 months (CI 95%: 9–41). In multivariate analysis (n=43), predictors of tumour response were body mass index (BMI) (odds ratio [OR]: 1.3; CI 95%: 1.04–1.63; P=0.022), functioning type of tumour (OR: 7.31; CI 95%: 1.26–42.5; P=0.027), arterial phase enhancement on abdominal computed tomography (CT) (OR: 8.11; CI 95%:1.06–62; P=0.044) and use of streptozotocin for cytotoxic agent (OR: 21.3; CI 95%: 1.48–306; P=0.025). Analysis of TTP predictors showed that BMI (hazard ratio [HR]: 0.85; CI 95%: 0.76–0.86; P=0.01) and arterial phase enhancement (HR: 0.3; CI 95%: 0.12–0.73; P=0.008) were associated with delayed progression. This large study confirms the previously reported results of TACE regarding its efficacy for the treatment of liver metastases of endocrine tumours. Arterial phase enhancement on abdominal CT and BMI are predictors of treatment's efficacy. Streptozotocin should be the preferred cytotoxic agent in order to save anthracycline for systemic chemotherapy.

Update on the management of neuroendocrine hepatic metastases

Neuroendocrine tumors (NETs) are rare and represent a diverse collection of malignancies that occur in many organ systems throughout the body, including the gastrointestinal and respiratory tracts. Unfortunately, the majority of patients with NETs have hepatic metastases at the time of diagnosis. Although some patients may be asymptomatic, others have unusual clinical presentations and variable tumor growth patterns. Although many patients have long indolent courses, without treatment, most patients die within 5 years of diagnosis. This article reviews the care of patients with NETs and hepatic metastases, with emphasis on the increasingly important role of oncologic image-guided interventions.

Survival and response after peptide receptor radionuclide therapy with [90Y-DOTA0,Tyr3]octreotide in patients with advanced gastroenteropancreatic neuroendocrine tumors

Because the role of chemotherapy, interferon, or somatostatin analogs as antiproliferative agents is uncertain, currently few treatment options exist for patients with metastatic or inoperable gastroenteropancreatic neuroendocrine tumors (GEP-NET). Fifty-eight patients with somatostatin receptor-positive GEP-NET were treated in a phase I dose-escalating study with cumulative doses of 47 mCi to 886 mCi of the radiolabeled somatostatin analog [(90)Y-DOTA(0),Tyr(3)]-octreotide. At baseline, 47 patients had progressive disease, and 36 were symptomatic. The extent of disease was: 4 patients without liver metastases and 52 patients with liver metastases, including 16 patients with very advanced disease, qualified as "end-stage," and 2 end-stage patients without liver metastases. The objective responses were 5 partial response (PR), 7 minor response (MR), 29 stable disease (SD), and 17 PD. Overall, 33 patients (57%) experienced some improvement in their disease status, including conversion from PD into SD and improvement from SD into MR. Accordingly, 21 of 36 patients (58%) had improvement in Karnofsky performance score or symptoms. The median overall survival (OS) was 36.7 months (95% confidence interval [CI] 19.4-54.1 months). The median progression-free survival in 41 patients who had at least stable disease at the end of the treatment period was 29.3 months (95% CI 19.3-39.3 months). Patients who had SD at baseline had a significantly better OS than patients who had PD at baseline. The extent of disease at baseline also was a significant predictive factor for OS. The OS after therapy with [(90)Y-DOTA(0),Tyr(3)]-octreotide was significantly better than in a historic control group of 32 comparable patients with GEP-NET who had been treated with another radiolabeled somatostatin analog, [(111)In-DTPA(0)]-octreotide (median OS 12.0 months, 95% CI 6.2-17.8 months). The difference in OS for both therapies remained highly significant in a multivariate Cox proportional hazard model including progression status and extent of disease at baseline as covariates. Although the objective response after therapy with [(90)Y-DOTA(0),Tyr(3)]-octreotide by standard criteria seems modest, the significantly longer OS compared with historic controls is most encouraging.

Selective hepatic artery embolization for treatment of patients with metastatic carcinoid and pancreatic endocrine tumors

BACKGROUND

Prognosis in patients with carcinoid and pancreatic endocrine tumors with diffuse, unresectable liver metastases is poor. Palliation is often difficult despite the use of somatostatin analogs, interferon alpha, or systemic chemotherapy. Several reviews have suggested that hepatic artery embolization, with or without intraarterial chemotherapy, can be used for control of symptoms and for cytoreduction in patients with liver dominant metastases.

METHODS

Between 2000 and 2002, 161 embolizations using polyvinyl alcohol or microspheres were performed on 84 patients with carcinoid or pancreatic endocrine tumors metastatic to the liver. A retrospective review was performed to evaluate symptomatic response, biochemical response, adverse effects, and duration of survival. Baseline and follow-up computed tomography scans were also assessed to determine radiographic response rates. Further analysis of survival was performed to assess the possible impact of various postembolization therapies.

RESULTS

Eighty-four patients underwent bland hepatic artery embolizations during the study period. Among 55 symptomatic patients, 44 patients had fewer symptoms, and among 35 patients whose tumor markers were followed, 28 had a major biochemical response. Objective radiographic responses were observed in 11 of 23 patients. No deaths occurred during therapy, and major toxicities were rare. Median overall survival was 36 months from time of initial embolization.

CONCLUSIONS

Hepatic artery embolization frequently results in clinical and radiographic responses in patients with unresectable liver metastases from carcinoid or pancreatic endocrine tumors. Morbidity is low when appropriate supportive care is provided. Hepatic artery embolization often results in regressions in patients with unresectable liver metastases from carcinoid or pancreatic endocrine tumors.

Treatment of Metastatic Disease in Patients with Neuroendocrine Tumors

Gastroenteropancreatic neuroendocrine tumors (GENTs) compromise a heterogeneous group of relatively uncommon neoplasms with a yearly incidence rate of 1.2 to 3.0 per 100,000 population. These tumors share numerous histologic and biologic features, allowing their consideration as a common entity. They are postulated to arise from neuroendocrine cells, but most are not from neural crest origin. Their predominant site of origin is the gastrointestinal tract, where most involve the small intestine and appendix, but are also found in the adrenal medulla, bronchopulmonary system, pancreas, thyroid, parathyroid, and paraganglia cells. A common feature is their often indolent course, but some tumors are poorly differentiated and behave aggressively. This article addresses the surgical management of endocrine malignancies and the treatment of metastatic disease in patients with neuroendocrine tumors.

Endocrine tumors of the pancreas

Neuroendocrine tumors of the pancreas are rare neoplasms of the heterogeneous group of neuroendocrine gastroenteropancreatic tumors that originate from totipotential stem cells or preexisting endocrine cells within the pancreas. Most neuroendocrine tumors of the pancreas are benign or show an indolent course of disease.A subset of them shows a very aggressive behavior, becomes highly malignant, and metastasizes early with life-limiting consequences. An effective disease-management includes the diagnostic approach with hormonal testing and localization and surgical treatment with histologic classification in combination with biotherapy, chemotherapy, or therapy with radionucleotides, de-pending on the individual behavior of the tumor. The primary goal is the improvement of symptoms leading to an acceptable quality of life in the individual patient.

A Phase II Study of Irinotecan with 5-Fluorouracil and Leucovorin in Patients with Pretreated Gastroenteropancreatic Well-Differentiated Endocrine Carcinomas

Only a few drugs are active in the treatment of well-differentiated endocrine carcinomas (WDEC). We evaluated the combination of the so-called 'de Gramont schedule' and irinotecan in these tumors in a phase II study.

METHODS

20 patients were enrolled in the study. The combination regimen included irinotecan, 180 mg/m(2) on day 1, followed by 200 mg/m(2) folinic acid in a 2-hour infusion, an intravenous 10-min bolus of 400 mg/m(2) 5-fluorouracil (5FU) and finally 600 mg/m(2) 5FU in a 22-hour infusion. Folinic acid and 5FU were repeated on day 2. Clinical, biological and morphological parameters were assessed by CT every 8 weeks. The site of the primary tumor was the pancreas in 10 cases, the lung in 3 cases and other sites in 7 cases. Sixteen patients had previously received chemotherapy, and 6 of them had had two lines of treatment. Six patients had previously been treated with chemoembolization.

RESULTS

The median number of cycles administered was 8. Grade 3-4 neutropenia was observed in 8 patients, and 1 patient experienced febrile neutropenia. There was no toxicity-related death. No complete symptomatic response was observed in 7 evaluable patients; 4 patients had an objective biological response. One patient achieved a morphological objective response, stabilization was observed in 15, but progression occurred in 3 patients. Median survival was 15 months.

CONCLUSION

The above-mentioned combination of LV5FU2 + irinotecan does not yield major activity in heavily pretreated unresectable metastatic gastroenteropancreatic WDEC, and significant toxicity was observed.

[Multiple endocrine neoplasia type 1 (MEN 1): clinical, biochemical and molecular diagnosis and treatment of the associated disturbances]

Multiple endocrine neoplasia (MEN) syndromes include types 1 (MEN 1) and 2 (MEN 2), von Hippel-Lindau syndrome, neurofibromatosis type 1 and Carney complex. These are complex genetic syndromes caused by activation or inactivation of different types of genes known to be involved in the regulation of cell proliferation. In this review we will discuss the clinical manifestations and management of the MEN 1 syndrome as well as the genetic screening of potential MEN 1 gene carriers. MEN 1 is a hereditary syndrome, transmitted in an autosomic dominant fashion and caused by an inactivating mutation of the MEN 1 gene, characterized by the development of primary hyperparathyroidism, islet cell tumors and pituitary adenomas. In addition, these patients can present with cutaneous manifestations such as angiofibromas and collagenomas, and can develop other neoplastic manifestations including carcinoids, thyroid tumors, adrenal adenomas, lipomas, pheochromocytomas and meningiomas. The MEN 1 gene encodes a peptide which is a tumor suppressor gene called menin. Several studies have demonstrated its importance in regulation of cell proliferation and have confirmed its role in the pathogenesis of the MEN 1 syndrome. The discovery of the MEN 1 gene and the genetic analysis of MEN 1 patients have resulted in earlier diagnosis and treatment of asymptomatic carriers which can potentially result in a longer survival of these patients. Further investigation of the function and signaling pathways of the menin protein will hopefully offer therapeutic alternatives to patients with malignant progression of MEN 1-related tumors and also result in improved survival.

Endocrine tumours of the pancreas

Endocrine pancreatic tumours (EPTs) are uncommon tumours occurring in approximately 1 in 100,000 of the population, representing 1-2% of all pancreatic neoplasms. Some of the tumours may be part of multiple endocrine neoplasia type one (MEN-1) syndrome or von Hippel-Lindau (vHL) disease. EPTs are classified as functioning or non-functioning tumours on the basis of their clinical manifestation. The biochemical diagnosis of EPT is based on hormones and amines released. Besides specific markers such as insulin, there are also general tumour markers such as chromogranin A, which is the most valuable marker and has been reported to be increased in plasma in 50-80% of patients with EPTs and correlates with tumour burden. The location of endocrine tumours of the pancreas includes different techniques, from endoscopic investigations to scintigraphy (e.g. somatostatin receptor scintigraphy) and positron emission tomography. The medical treatment of endocrine pancreatic tumours consists of chemotherapy, somatostatin analogues and alpha-interferon. None of these can cure a patient with malignant disease. In future, therapy will be custom-made and based on current knowledge of tumour biology and molecular genetics.

Advances in the treatment of neuroendocrine tumors

Gastrointestinal neuroendocrine tumors are characterized by generally slow growth rates and the ability to secrete a variety of hormones and biogenic amines. For patients with localized disease, surgical resection alone is often curative; however, patients with metastatic disease often present a therapeutic challenge. Although somatostatin analogs are highly effective in controlling symptoms of hormonal secretion, they are rarely associated with tumor regression. Selected patients with hepatic metastases may benefit from surgical debulking, embolization, or other ablative therapies. The clinical benefit associated with the administration of systemic agents such as alpha interferon or cytotoxic chemotherapy is less clear, and the widespread use of such regimens has been limited by their relatively modest antitumor activity as well as by concerns regarding their potential toxicity. The highly vascular nature of neuroendocrine tumors has led to interest in angiogenesis inhibition as a potentially novel treatment strategy. In addition, several small molecule tyrosine kinase inhibitors are currently being evaluated in a Phase II setting. The naturally indolent growth of neuroendocrine tumors presents a challenge in interpreting efficacy endpoints from small Phase II studies. Larger, randomized trials, along with the evaluation of surrogate endpoints of biologic activity, may be necessary to establish the potential clinical benefit of these novel agents.

Malignant insulinoma: spectrum of unusual clinical features

BACKGROUND

Malignant insulinoma occurs in a few patients with insulinoma. Due to the small sample of patients, there are little data regarding their clinical manifestation as well as the preferred treatment modalities. The aims of the current study were to summarize the National Institutes of Health experience during the last two decades and to conduct a critical review of the current literature.

METHODS

The authors identified 10 patients with metastatic insulinoma.

RESULTS

The patients presented with four patterns of clinical behavior. First, four patients presented with lymph node metastasis and, after surgical excision, maintained a prolonged tumor-free survival. Second, four patients presented with metastatic disease to the liver, which appeared years after the initial diagnosis and presumed curative surgery. Third, one patient presented with a large alpha-fetoprotein-secreting liver mass. Finally, 9 of the 10 patients had a prolonged survival. Various treatment modalities were used to control hypoglycemia. Short-term benefits were most often achieved with embolization and diazoxide. Less successful modalities included radiofrequency ablation, radical debulking surgery, verapamil therapy, octreotide therapy, and chemotherapy.

CONCLUSIONS

The current study, as well as others, suggested that metastatic insulinoma may have a variable natural history. After the initial surgical resection, the biology of the tumor, rather than any treatment modality, was most likely the major determinant of long-term survival.

Endocrine tumours of the gastrointestinal tract: Chemotherapy

Malignant neuroendocrine tumours are less sensitive to chemotherapy than other epithelial malignancies. If chemotherapy is considered, tumours of pancreatic origin have a higher sensitivity than tumours from the gastrointestinal tract ('carcinoids'). Chemotherapy with streptozocin combinations and with dacarbazine should be considered in patients with progressive malignant neuroendocrine tumours of the pancreas. A favourable response to chemotherapy can be expected in up to 60% of patients receiving a combination of streptozocin plus doxorubicin, and in up to 40% of patients receiving dacarbazine. A survival benefit has been shown for streptozocin combinations. Treatment regimens are effective in functioning and non-functioning tumours. The response to treatment cannot be predicted. Poorly differentiated neuroendocrine tumours, independent of their origin, respond to a combination of etoposide plus cisplatin. Chemotherapy is, however, almost ineffective in patients with well-differentiated neuroendocrine tumours originating in the gastrointestinal tract ('carcinoids').

Radiolabeled somatostatin analog [177Lu-DOTA0,Tyr3]octreotate in patients with endocrine gastroenteropancreatic tumors

PURPOSE

There are few treatment options for patients with metastasized or inoperable endocrine gastroenteropancreatic (GEP) tumors. Chemotherapy can be effective, but the response is usually less than 1 year. Here, we present the results of treatment with a radiolabeled somatostatin analog, [177Lu-DOTA0,Tyr3]octreotate (177Lu-octreotate).

PATIENTS AND METHODS

One hundred thirty-one patients with somatostatin receptor-positive tumors were treated with up to a cumulative dose of 600 to 800 mCi (22.2 to 29.6 GBq) of 177Lu-octreotate.

RESULTS

One patient developed renal insufficiency, and another patient developed hepatorenal syndrome. Creatinine clearance did not change significantly in the other patients. WHO hematologic toxicity grade 3 or 4 occurred after less than 2% of the administrations. We observed complete remission in three patients (2%), partial remission in 32 patients (26%), minor response (tumor diameter decrease of 25% to 50%) in 24 patients (19%), stable disease (SD) in 44 patients (35%), and progressive disease (PD) in 22 patients (18%). Higher remission rates were positively correlated with high uptake on pretherapy somatostatin receptor imaging and a limited number of liver metastases, whereas PD was significantly more frequent in patients with a low performance score and extensive disease. Median time to progression in 103 patients who either had SD or tumor regression was more than 36 months.

CONCLUSION

Treatment with 177Lu-octreotate results in tumor remission in a high percentage of patients with GEP tumors. Serious side effects are rare. The median time to progression compares favorably with chemotherapy. Results are better in patients with a limited tumor load. Therefore, early treatment, even in patients who have no PD, may be better.

Treatment of insulinoma in a springer spaniel with streptozotocin

An eight-year-old, female springer spaniel was treated for metastatic insulinoma with a single intravenous dose of 500 mg/m2 streptozotocin (SZN), and pre- and post-treatment diuresis. A tapering dose of corticosteroids was also administered over a 28 day period. SZN and corticosteroid administration resulted in resolution of hypoglycaemia and subsequent development of diabetes mellitus. Further metastases caused cervical spinal pain and the dog was euthanased 118 days after SZN administration. SZN can be safely used for the treatment of canine insulinoma, but, when compared with other published cases, a marked variation in clinical response to this drug exists and further study is warranted.

Lack of efficacy of streptozocin and doxorubicin in patients with advanced pancreatic endocrine tumors

BACKGROUND

The combination of streptozocin and doxorubicin has been considered the standard palliative chemotherapy regimen in patients with advanced pancreatic endocrine tumors (PETs). However, a recent review failed to confirm high antitumor activity in patients with advanced PETs.

METHODS

We retrospectively reviewed the records of 16 consecutive patients who received streptozocin and doxorubicin for advanced PETs at Dana Farber/Partners Cancer Care institutions. Baseline patient characteristics, radiographic response to therapy, treatment-related toxicity, progression-free and overall survival were analyzed.

RESULTS

One patient demonstrated an objective partial response to therapy (objective response rate [ORR], 6%; 95% confidence interval [CI], 0-18%). Six patients achieved stable disease (38%; 95% CI, 14-62%) and 9 patients demonstrated disease progression on initial restaging (56%; 95% CI, 33-77%). The median progression-free survival and overall survival were 3.9 months (95% CI, 2.8-8.8) and 20.2 months (95% CI, 9.7-37.4), respectively.

CONCLUSIONS

In this retrospective cohort, the combination of streptozocin and doxorubicin failed to demonstrate substantial antitumor activity in patients with advanced PET. Our findings underscore the need for new therapeutic options in this patient population.

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.

Current concepts in functioning endocrine tumors of the pancreas

Duodenal and pancreatic endocrine tumors are uncommon and their surgical treatment is often difficult. The management of these tumors has changed with recent advancements in tumor localization, intraoperative hormone measurements, standardized surgical techniques, and a better understanding of the genetic basis of multiple endocrine neoplasia syndrome. We present our experience with 191 endocrine tumors and elaborate the contemporary management of functioning duodenopancreatic endocrine tumors.

Management of nonfunctioning islet cell tumors

AIM: To more clearly define the clinical and pathological characteristics and appropriate diagnosis and treatment of nonfunctioning (NFICTs) islet cell tumors, and to review our institutional experience over the last 30 years.

METHODS: The records of 43 patients confirmed to have nonfunctioning islet cell tumors of pancreas were retrospectively reviewed. Survival was estimated by the Kaplan-Meier methods and potential risk factors for survival were compared with the log-rank tests.

RESULTS: The mean age was 31.63 years (range, 8 to 67 years). There were 7 men and 36 women. Twenty-eight patients had a confirmed diagnosis of nonfunctioning islet cell carcinoma (NFICC) and benign islet cell tumors were found in 15 patients. The most common symptoms in patients with NFICTs were abdominal pain (55.8%), nausea and/or vomiting (32.6%), fatigue (25.6%) and abdominal mass (23.3%). Preoperative ultrasonic and computed tomography localized the tumors in all patients. Forty-three NFICTs were distributed throughout the pancreas, with 21 located to the right of the superior mesenteric vessels, 10 in the body of the pancreas, 6 in the tail of the pancreas, and multiple tumors were found in one patient. Thirty-nine of 43 patients (91%) underwent surgical resection. Surgical treatment was curative in 30 patients (70%) and palliative in 9 (21%). The resectability and curative resection rate in patients with NFICC of pancreas were 89% and 61%, respectively. The overall cumulative 5-year and 10-year survival rates for patients with NFICC were 58.05% and 29.03%, respectively. Radical operation and diameter of cancer small than 10 cm were positive prognostic factors in females younger than 30 years old. Multivariate Cox regression analysis indicated that radical operation was the only independent prognostic factor, P = 0.007.

CONCLUSION: Nonfunctioning islet cell tumors of pancreas are found mainly in young women. The long-term results for patients undergone surgery, especially curative resection are good.

The diagnosis and medical management of advanced neuroendocrine tumors

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

The doxorubicin-streptozotocin combination for the treatment of advanced well-differentiated pancreatic endocrine carcinoma; a judicious option?

Due to their rarity, only few trials have studied the role of the doxorubicin-streptozotocin (DS) combination in advanced well-differentiated pancreatic endocrine carcinomas (AWDPEC). However, the published results are inconsistent. We reviewed all AWDPEC (5-year period, 45 patients) treated in our institution with the DS combination for: objective response rate (ORR), progression-free survival, overall survival (OS) and toxicity. An ORR of 36% (95% Confidence Interval (CI) 22-49) was obtained, with 16 partial responses (PR). The mean duration of PR was of 19.7 months. Two and 3-year OS rates were 50.2 and 24.4%, respectively. Toxicities were mainly digestive (grade > or =3 vomiting, 13%) and haematological (grade > or =3 neutropenia, 24%). Previous systemic chemotherapy and malignant hepatomegaly were associated with a poorer ORR (P=0.033, P=0.016) and OS (P=0.008, P=0.045). Multivariate analysis demonstrated previous chemotherapy as the only independent predictive-factor for survival (P=0.013). In conclusion, our data confirm the sensitivity of AWDPEC to the DS combination, with an ORR of 36% and a remarkable median response duration of 19.7 months, and suggests that it could be considered as a valid option in first-line therapy.

Islet cell tumor arising from a heterotopic pancreas in the duodenal wall with ulceration

A rare case of symptomatic islet cell tumor arising from heterotopic pancreas in the duodenum with ulceration is described. Gastrointestinal bleeding was the only sign observed in this patient. Tagged red blood cell scan, upper endoscopy, and computed tomography scan showed active bleeding ulcer from a periampullary mass. Removal of the submucosal tumor was done to prevent future re-bleeding. Histologic and immunohistochemical characterization of the tumor showed an endocrine tumor that expressed a variety of endocrine peptides.

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.

Chemotherapy for gastro-enteropancreatic endocrine tumours

Despite similar histological and morphological aspects, gastro-enteropancreatic (GEP) endocrine tumours represent a heterogeneous group of tumours with varying clinical expression depending on tumour type (functional or not), origin and extension, but also on histological differentiation and proliferative capacity. The natural history of well-differentiated tumours is often favourable without treatment and GEP endocrine tumours may remain indolent for many years. Chemotherapy may however be indicated in the presence of symptomatic non-progressive disease (progression evaluated over 3-6 months). In contrast, poorly differentiated GEP endocrine tumours are frequently aggressive and early treatment is required. Accurate staging is mandatory and where surgery is possible (even in the event of limited metastatic disease), this option should be re-evaluated in a multidisciplinary approach. Approximately 2/3 of malignant GEP tumours are metastatic at discovery and surgery is possible in a minority of patients; therefore, chemotherapy, with/without other strategies (e.g. local ablation), is frequently indicated in patients with symptomatic, bulky or progressive disease. For well-differentiated pancreatic tumours, the reference association is Adriamycin with streptozotocin yielding objective responses (OR) in 40-60% of patients. Prolonged treatment is limited due to potential cardiotoxicity of Adriamycin and standard 2nd-line regimens are not of proven efficacy; thus, other treatment modalities are usually additionally required (e.g. chemo-embolisation). A significant OR may render a small number of patients secondarily amenable to surgery. Published series evaluating chemotherapy for midgut endocrine tumours are outdated and disappointing. Objective response rates with combined associations (including either 5-fluorouracil and/or streptozotocin) rarely exceed 20% and where possible, chemo-embolisation for hepatic metastases combined with somatostatin analogues (+/- interferon) should be preferred. Poorly differentiated GEP tumours are generally aggressive tumours with metastases at diagnosis and tend to progress rapidly. Surgery is rarely possible and ineffective even in locally advanced disease due to a high risk of recurrence. Chemotherapy, using cisplatin and etoposide, is the reference treatment and frequently yields OR rates >50%. However, despite being chemosensitive, disease control is limited (8-10 months). Overall, advances in therapeutic chemotherapeutic options are required in the management of all types of advanced GEP endocrine tumours and evaluation of new drugs (e.g. irinotecan) and combination strategies (chemotherapy with local ablative therapies) are required in the future.

Treatment of neuroendocrine tumours with infusional 5-fluorouracil, folinic acid and streptozocin

A standardised, effective systemic therapy for metastatic neuroendocrine tumours (NETs) has not been established to date. We reviewed the management of 15 patients with inoperable, metastatic NET treated systematically with a combination chemotherapy regimen of infusional 5-fluorouracil, folinic acid and streptozocin. Overall objective response rate was 53% and tolerability was excellent.

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.

Optimal Treatment of Zollinger-Ellison Syndrome and Related Conditions in Elderly Patients

Zollinger-Ellison syndrome is characterised by refractory peptic ulcer disease, severe diarrhoea and gastric acid hypersecretion associated with an islet-cell tumour of the pancreas (gastrinoma). The true incidence and prevalence of this rare disease is unknown; in the US, the frequency is one per one million people and the age at presentation varies from 7 to 90 years. Zollinger-Ellison syndrome is sporadic in 62-80% of cases and in 20-38% of cases is associated with multiple endocrine neoplasia type 1 (MEN 1). The diagnosis of Zollinger-Ellison syndrome is certain when the plasma gastrin is >1000 pg/mL and the basal acid output is >15 mEq/h in patients with an intact stomach, >5 mEq/h in gastrectomised patients, or when this hypergastrinemia is associated with a pH <2. The treatment is based on control of gastric acid hypersecretion and of the malignant tumour and its possible metastases. Proton pump inhibitors are the most effective antisecretory drugs and can be administered in the elderly at high dosages without drug-related adverse effects. As an initial therapy, daily dosages of omeprazole 80-100 mg or pantoprazole 40-160 mg are employed. In long-term treatment the doses can be greatly reduced once effective control of the gastric output has been established. Intravenous proton pump inhibitors may be administered when patients cannot take oral therapy, particularly in acute conditions. All sporadic localised gastrinomas should be excised if possible. When liver metastases are also present, their debulking may improve symptoms and survival, and facilitate medical treatment. There is some controversy as to the surgical approach for gastrinomas associated with MEN 1. Somatostatin analogues can be useful in reducing gastric acid hypersecretion, serum gastrin and gastric enterochromaffin-like (ECL) cells and can thus contribute to treating the disease more effectively. Their antiproliferative effect can be used in treating liver metastases. Chemotherapy is not the therapy of choice in patients with gastrinomas and is indicated only in those with malignant progressive disease; interferon alpha, embolisation and chemoembolisation are not advisable for the elderly. The treatment of elderly Zollinger-Ellison syndrome patients, similarly to all elderly oncological patients, should be based on the use of comprehensive geriatric assessment. This will enable the clinician to define the functional status of the elderly person, to decide whether the patient can tolerate surgery and/or the stress of antineoplastic therapy, and finally, to determine whether this patient can tolerate an aggressive treatment for Zollinger-Ellison syndrome or whether the only possible choice is palliative relief of symptoms.

Treatment of malignant endocrine pancreatic tumors with a combination of alpha-interferon and somatostatin analogs

Somatostatin analogs and alpha-interferon induce good responses as single drugs in the treatment of endocrine pancreatic tumors. We examined the efficacy and tolerability of the combination of alpha-interferon and somatostatin analogs in 16 patients with metastatic endocrine pancreatic tumors. All patients except one had received prior treatment and were in a progressive state. Doses of alpha-interferon and somatostatin analogs were individually titrated. The alpha-interferon doses varied between 9 and 25 million units per week and were combined with 100-1500 microg of octreotide or 6000 microg of lanreotide daily. Radiological response was seen in 3 of 16 (19%) patients (median duration 23 mo). Biochemical response was seen in 10 of 16 (62.5%) patients (median duration 22 mo). All three patients previously progressing on both alpha-interferon and somatostatin analog as single drugs achieved a stabilization of the disease when treated with the combination (median duration 10 mo). Seven of eight (88%) patients previously progressing on alpha-interferon treatment benefited from the combination with biochemical partial response or stabilization. All six patients previously progressing during somatostatin analog treatment achieved biochemical partial response or stabilization. More than 80% of patients who progressed during previous treatment with either drug benefited from the combined treatment, which also was well tolerated. Thus, a combination of alpha-interferon and somatostatin analogs may be considered for patients previously progressing on treatment with alpha-interferon or somatostatin analogs. However, in this study, the value of sequential treatment has not been evaluated.

Nonfunctioning Islet Cell Carcinoma of the Pancreas: Case Report

Islet cell carcinomas have an incidence of 5 per million per year; 50 per cent of these are nonfunctioning islet cell tumors. The presenting symptoms mimic pancreatic ductal adenocarcinoma. The CT finding of a pancreatic head mass that spares the main duct may distinguish between the two. The treatment of choice is resection. Most nonfunctioning islet cell tumors are not discovered until metastases are present. However, favorable survival rates have been reported in locally advanced tumors that have undergone resection. Liver metastases carry an unfavorable prognosis. Five-year survival over 60 per cent has been reported. Node-negative patients have a median survival of more than 10 years, and node-positive patients who have undergone resection have a median survival of 75 months. Streptozotocin and 5-fluorouracil are used postoperatively in patients with advanced disease. Considering the favorable survival with resection aggressive surgical treatment is mandated in cases of nonfunctioning islet cell tumors.

Prospective study of the antitumor efficacy of long-term octreotide treatment in patients with progressive metastatic gastrinoma

BACKGROUND

Malignant pancreatic endocrine tumors (PETs) have a poor prognosis and existing antitumor treatments are unsatisfactory. Recent studies have shown somatostatin analogues to have antitumor growth effects in patients with malignant PETs; however, to the authors' knowledge, little information exists regarding their efficacy or effect on survival in patients with progressive malignant gastrinoma, the most common symptomatic malignant PET. The purpose of the current study was to study prospectively the efficacy, safety, and effect on survival of long-term treatment with octreotide in consecutive patients with progressive malignant gastrinoma.

METHODS

Fifteen consecutive patients with malignant gastrinoma with progressive hepatic metastases were studied. All patients underwent conventional imaging studies (computed tomography scan, magnetic resonance imaging, ultrasound, and, if needed, selective angiography) and somatostatin receptor scintigraphy prior to treatment and at 3-6-month intervals while receiving treatment. The patients all were treated initially with octreotide, 200 microg every 12 hours, and at last follow-up were being maintained on long-acting release octreotide, 20-30 mg every month. Tumor size and/or number were used to classify patient responses as either no tumor response or tumor response (stabilization or decrease in size). Treatment response was correlated with tumor and clinical characteristics.

RESULTS

Tumors in 8 of the 15 patients studied (53%) responded at 3 months, with 47% (7 of 15 patients) demonstrating tumor stabilization and 6% (1 of 15 patients) demonstrating a decrease in tumor size. The mean duration of response was 25.0+/-6.1 months (range, 5.5-54.1 months). Six of the eight responders were continuing to respond at the time of last follow-up. Tumor response did not correlate with any clinical parameter (e.g., tumor extent, fasting gastrin, or acid secretory rates). However, slow-growing tumors were more likely to respond prior to treatment (86% vs. 0%) (P < 0.0014). During follow-up (range, 4-8 years), 25% of the responders died compared with 71% of the nonresponders, a difference that approached statistical significance (P = 0.10). Two patients (13%) developed serious side effects that required the withdrawal of octreotide.

CONCLUSIONS

Octreotide is an effective antitumor treatment in patients with progressive malignant gastrinoma. In approximately 50% of these patients octreotide has an antigrowth effect; treatment is associated with a low incidence of serious side effects compared with other antitumor treatments commonly used and, in contrast to many studies, the growth response is long-lasting. The results of the current study suggest that octreotide treatment should replace chemotherapy as the standard treatment for these patients, especially those patients with slow-growing tumors. Additional studies involving larger numbers of patients will be needed to determine a convincing effect on survival.