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

Metastatic islet cell tumor with ACTH, gastrin, and glucagon secretion. Clinical and pathologic studies with multiple therapies

A patient with metastatic islet cell carcinoma demonstrated multiple clinical syndromes simultaneously with secretion of ACTH, gastrin, glucagon, and serotonin. Hepatic arterial embolization resulted in an initial decrease in all secretory products, which was sustained for glucagon and serotonin. Recrudescence of the Cushings and Zollinger-Ellison syndrome was managed by surgical extirpation of the primary tumor and regional metastases as well as bilateral adrenalectomy. Electron microscopy and immunocytochemistry of the primary tumor and the metastatic lesions revealed the presence of multiple types of granules within single cells and, different patterns of secretory profiles in different tumor sites.

VIPoma syndrome

Since the description of the watery diarrhea syndrome by Verner and Morrison 29 years ago, clinical and experimental observations have elucidated the pathophysiology of this disease. Vasoactive intestinal polypeptide (VIP) is produced and released by a tumor of the pancreatic islets or by a tumor of neural crest origin such as a ganglioneuroma. Under normal conditions, current evidence suggests that VIP is a neurotransmitter in the central and peripheral nervous systems and particularly in the peptidergic nervous system. The low VIP plasma concentration observed in healthy subjects is viewed as a neuronal overflow since it has been impossible to ascertain any endocrine role for circulating VIP. Markedly elevated VIP plasma levels in the VIPoma syndrome lead to intestinal secretion with severe secretory diarrhea, resulting in hypovolemia, hypokalemia, and acidosis. These symptoms subside after successful tumor removal. Approximately 50 percent of patients have metastatic spread at the time of diagnosis. For these patients, a new and promising therapeutic modality is available in the form of a subcutaneously administered somatostatin analogue that relieves symptoms through potent inhibition of VIP release from tumor tissue.

Glucagonoma syndrome

The glucagonoma syndrome is characterized by a necrolytic migratory erythematous rash, angular stomatitis, painful glossitis, a normochromic normocytic anemia, mild diabetes mellitus, weight loss, a tendency to thrombosis, and neuropsychiatric disturbances. The diagnosis is made by finding a high plasma glucagon concentration in the absence of any other cause, such as renal failure or severe stress. A pancreatic alpha-cell tumor can be identified and stained by immunocytochemistry with glucagon antibodies. Optimal treatment is surgical removal, but approximately 50 percent of the tumors have metastasized by the time of diagnosis. Since the tumor is slow-growing, remission can be obtained by hepatic artery embolization to shrink hepatic secondaries or by shrinkage, in about 10 percent of patients, with the combination chemotherapeutic regimen of 5-fluorouracil and streptozotocin. The rash frequently responds to administration of zinc, a high-protein diet, and control of the diabetes with insulin. Alongside the alpha cell in the islets of Langerhans is the D-cell, which produces somatostatin and may well act physiologically as a paracrine inhibitor of glucagon release. A newly developed, long-acting somatostatin analogue, SMS 201-995, which the patient can self-administer as a subcutaneous injection, has proven effective in suppressing glucagon secretion from glucagonomas and, in some cases, causing remission of clinical symptoms.

N-methyl antitumour agents. A distinct class of anticancer drugs?

This article reviews the structure-activity characteristics, mode of action, pharmacokinetics and clinical utility of a group of chemically dissimilar antitumour agents which have as a common structural feature the N-methyl moiety. The importance of this feature is shown by the fact that molecules without a substituent on the nitrogen or compounds with N-alkyl groups other than methyl are usually inactive in experimental systems. This observation is supported by structure-activity studies with N-alkyl derivatives of s-triazines, triazenes, formamides, hydrazines and nitrosoureas. Representatives of these structural types which have found clinical application are, respectively, hexamethylmelamine, dacarbazine, N-methylformamide, procarbazine and streptozotocin. Mode of action studies have shown that dacarbazine, procarbazine and streptozotocin can give rise to species capable of methylating nucleic acid. This may be the lesion which produces antitumour activity. The mechanism of action of N-methylmelamines and N-methylformamide remains unclear. There is good evidence that, with the exception of N-methylnitrosoureas, host metabolism is prerequisite for activity with these agents. Although not pronounced, the clinical activity of N-methyl antitumour agents is useful, particularly as activity is not associated with severe haematological toxicity. Furthermore, responses may be observed in patients resistant to bifunctional alkylating agents. It is concluded that the drugs reviewed herein show a degree of coincidence in terms of their biological properties which may warrant a common classification. The term N-methyl antitumour agent is proposed.

Diagnosis and treatment of hypoglycemic disorders

Many other hypoglycemic states can be confused with an insulinoma. This article presents the diagnosis, localization, and therapy of these islet cell tumors. Also presented is a discussion of the role of nesidioblastosis in persistent hyperinsulinemic hypoglycemia in the neonate.

Somatostatin analogue SMS 201-995 long term therapy for vipoma

The definitive treatment of a pancreatic tumour secreting vasoactive intestinal polypeptide is surgical removal of the tumour, but when curative resection is not possible symptomatic treatment of the endocrine hyperfunction is important. Streptozotocin, although effective for palliation, can involve unpleasant side effects. We report the long term use of subcutaneous somatostatin analogue SMS 201-995 in an elderly man presenting with severe watery diarrhoea and anaemia due to a pancreatic vipoma. Good symptomatic improvement has been achieved with no side effects over a period of 24 months. We suggest there is a use for subcutaneous SMS 201-995 in elderly patients with inoperable pancreatic gut hormone producing tumours with metastases and in those where surgery would carry a high operative risk.

Glucagonoma syndrome. Rapid response following arterial embolization of glucagonoma metastatic to the liver

Transcatheter arterial embolization was used to treat a patient with glucagonoma metastatic to the liver after chemotherapy failed. Rapid amelioration of the syndrome's manifestations followed.

Successful treatment of glucagonoma-related necrolytic migratory erythema with dacarbazine

A 63-year-old man with a glucagonoma syndrome is described. The diagnosis was confirmed by necrolytic migratory erythema, which is the most distinctive feature of the clinical syndrome. There was no chance of operative resection of the tumor because of liver metastases at the time of diagnosis. The patient was treated with dacarbazine. During this treatment the skin lesions disappeared completely.

Neuroendocrine tumors. A European view

A center in Belfast, Northern Ireland, has established a register for tumors of the gastroenteropancreatic endocrine system. Carcinoid tumors occur most frequently. Of the non-carcinoid tumors, insulinomas, gastrinomas, and unknown types have the highest incidence, with other types being extremely rare. The potentially remediable nature of the tumors is stressed, and frequently a good quality of life can be experienced even in the presence of metastatic disease. The syndromes are probably underdiagnosed as they present with clinical features for which there are more common explanations, and appropriate diagnostic methods are therefore not used. The management of the syndromes is reviewed with particular emphasis on the treatment of patients with inoperable disease. Histamine (H2)-receptor antagonist therapy has made an impact in Zollinger-Ellison syndrome, and streptozotocin and somatostatin analogues can control tumor growth and endocrine syndromes, respectively.

Somatostatin analogue (SMS 201-995) in the management of gastroenteropancreatic tumors and diarrhea syndromes

SMS 201-995 (Sandostatin) was studied using low doses (50 to 100 micrograms) administered subcutaneously every 12 hours. A single 50-micrograms dose of SMS 201-995 effectively controlled gastric acid and blood gastrin levels for 12 hours in three patients with benign gastrinomas and was useful in their perioperative management. Higher doses of the agent (500 to 800 micrograms per day) had no effect on metastases in one of two patients with metastatic gastrinoma. In the other patient, one tumor shrank but the other continued to grow after three months of treatment while serum gastrin levels did not change. Cultured metastatic tumor tissue from this patient released different forms of gastrin; growth rates varied, independent of uptake of SMS 201-995, and gastrin release increased. A neonate with nesidioblastosis maintained normal blood glucose levels while receiving SMS 201-995 therapy following a 95 percent pancreatic resection. In two elderly patients with organic hypoglycemia--one with a single benign adenoma and one with multiple adenomatosis--the somatostatin analogue did not prolong the hypoglycemia-free interval. In nine patients with carcinoid syndrome, flushing was uniformly controlled with 50 micrograms of SMS 201-995 administered every eight to 12 hours. One of the nine required exocrine pancreatic replacement. After six months of treatment, three of the nine had no change in tumor size and one had remission of symptoms and stopped treatment. In two patients with vipoma, SMS 201-995 controlled diarrhea and reduced levels of vasoactive intestinal peptide; tumor necrosis occurred in one patient. In a patient with diabetic diarrhea unresponsive to all treatments, SMS 201-995 therapy controlled the diarrhea but did not interfere with control of the diabetes.

Treatment of malignant endocrine pancreatic tumours with human leucocyte interferon

22 patients with advanced malignant endocrine pancreatic tumours were treated with human leucocyte interferon 3-6 X 10(6) IU per day. Objective responses (more than 50% reduction in tumour markers or tumour size) were seen in 7/7 with watery diarrhoea/hypokalaemia/achlorhydria syndrome, 3/4 with the Zollinger-Ellison syndrome, 6/9 with "non-functioning" tumours, and 1 with a mixed tumour mainly producing somatostatin. The median duration of response was 8.5 months, and all responders improved clinically. Adverse effects seemed more tolerable than those of cytotoxic treatment.

Bone metastases in malignant gastrinoma

Six patients (4 women, 2 men) with malignant gastrinoma developed multiple bone metastases; osteolytic as well as osteoblastic lesions occurred. All lesions involved the central skeleton, most caused symptoms, and, in 2 cases, there was associated hypercalcemia with normal serum parathormone levels. Poor responses were observed after treatment with cytotoxic drugs, but good symptomatic responses occurred after radiotherapy in 2 of the 4 patients in whom it was used. The peptic ulcer component of the disease was well controlled in all patients by cimetidine with or without anticholinergic supplements or by ranitidine alone in doses of 300-600 mg daily. Five of the 6 patients died with a mean survival after diagnosis of Zollinger-Ellison syndrome of 3.3 yr (range 1.0-7.0 yr), suggesting that bone metastases are associated with a poor prognosis in metastatic gastrinoma.

Nephrotoxicity induced by cancer chemotherapy with special emphasis on cisplatin toxicity

Renal failure in cancer patients is a common problem in oncology; this complication is frequently multifactorial in origin. Several antineoplastic agents are potentially nephrotoxic; previous renal impairment as well as combinations with other nephrotoxic drugs may increase the risk of nephrotoxicity during administration of chemotherapy. Methotrexate-related renal damage most frequently occurs with high-dose therapy and can be avoided by forced alkaline diuresis and administration of folinic acid. Renal dysfunction secondary to semustine (CH3-CCNU) is clearly related to cumulative doses in excess to 1,200 mg/m2; the onset may be delayed and renal failure progress despite drug discontinuation. Streptozotocin is also nephrotoxic and may cause proteinuria and renal tubular acidosis; progressive renal failure can be predicted by a close monitoring of proteinuria and prevented by drug discontinuance. Mitomycin-associated renal failure frequently presents with signs of microangiopathic hemolytic anemia; renal failure is usually delayed but occasionally, it may be rapidly progressive despite drug discontinuance. Cisplatin nephrotoxicity is clearly dose-related and used to be considered dose limiting. Renal insufficiency can be prevented by hydration and forced diuresis; in addition, hyperhydration with mannitol-induced saline diuresis may allow administration of high doses and thus circumvent the dose-limiting effect of cisplatin-induced renal toxicity. Cisplatin-induced renal magnesium wasting occurs frequently and should be supplemented. Other approaches to reduce cisplatin nephrotoxicity are currently under investigation and are discussed.

Current management of Zollinger-Ellison syndrome

Patients with Zollinger-Ellison syndrome require that management decisions be made to control the gastric acid hypersecretion and treatment directed at the gastrinoma itself. The advent of newer antisecretory drugs and increased knowledge of the natural history of this disease have led to major changes in the management of each of these two areas. Recent studies have demonstrated that treatment with the currently available histamine H2-receptor antagonists (cimetidine, ranitidine) with or without an anticholinergic agent will control gastric acid secretion in almost all patients. These studies have also shown that most patients require higher doses than those used routinely to treat peptic ulcer, treatment is only successful if an adequate dose of antisecretory drug is used and must be monitored by measuring gastric acid hypersecretion, and established criteria to regulate the dose must be used. Newer more potent antisecretory drugs such as famotidine or omeprazole will facilitate management of gastric hypersecretion but are not yet currently available. Highly selective vagotomy should be considered in those patients who require high doses of cimetidine or ranitidine. Total gastrectomy should be reserved for those patients unwilling or unable to take oral medication. Although aggressive surgery is not warranted in most patients because overall prognosis is excellent, tumour status should be assessed in all patients by imaging studies (CT scan, ultrasound, selective angiogram). Patients without metastatic disease and without the MEN-1 syndrome (multiple-endocrine-neoplasia type 1) should undergo exploratory laparotomy by a surgeon experienced in treating this disease, with studies suggesting a cure rate of approximately 20%.(ABSTRACT TRUNCATED AT 250 WORDS)

Gastrinoma

Although there are multiple etiologies of clinical hypergastrinemia, the most important cause is gastrinoma [Zollinger-Ellison (ZE) syndrome]. The most significant advance in the management of patients with the ZE syndrome has been the development of the ability to establish firmly the correct preoperative diagnosis by radioimmunoassay. We believe that all patients who have the ZE syndrome should undergo operation for two reasons: to identify and resect all tumor and because in patients in whom no tumor is found or in whom all tumor cannot be resected, the most reliable relief of hypersecretory symptoms for the life of the patient can be achieved by total gastrectomy.

Advances in rational combination chemotherapy

Due to the high frequency of micro- or macrometastatic disease at the time of diagnosis of cancer, and to the increasing prevalence of cancer in this country, the use of chemotherapy to evoke cure or prolongation of survival has become critically important. In addition, the growth kinetics of large tumor burdens and the high probability of drug-resistant cells in a tumor mass at the time of diagnosis necessitate combinations of chemotherapeutic agents rather than single agents as the most effective mode of treatment. Since there are 40 to 50 active anticancer drugs now utilized, and since synergy between drug combinations is often dose and/or schedule dependent, the number of possible drug combinations and permutations is vast. Thus, screening for effective drug combinations requires a rational approach which will allow for accurate predictions of synergy. Most advances in this scientific approach have utilized biochemical modulation in conjunction with in vitro cytotoxicity assays, in particular, clonogenic assays. Such an approach has generated a number of drug combinations, such as sequential MTX-5FU, with widely applicable clinical efficacy. The continued use of biochemical modulation should rapidly generate new effective drug combinations which will, hopefully, allow us to cure even those cancers presently considered incurable.

Neuroendocrine tumours of the gut: long-term therapy with the somatostatin analogue SMS 201-995

Nine patients with metastatic neuroendocrine tumours of the gut were treated for over 100 days with the long-acting octapeptide of somatostatin, SMS 201-995. Two patients had unusually aggressive tumours (neuroendocrine tumours are typically slow-growing) with only modest elevation of tumour secretory products. SMS 201-995 was given in an attempt to slow tumour growth, but tumour size continued to increase. Three patients had glucagonomas and uncontrolled skin rashes, and four patients had VIPomas, which caused uncontrolled watery diarrhoea. SMS 201-995 was given principally to reduce hypersecretion of hormones from their tumours and to relieve symptoms. All the patients experienced rapid relief of their symptoms when SMS 201-995 treatment was introduced, and symptomatic control was maintained throughout treatment except in one patient, who required a supplementary procedure (pancreatic primary tumour embolization). Circulating peptide levels were initially suppressed, but continued suppression did not occur in every case despite good clinical control. It seems likely that SMS 201-995 has beneficial effects on target organs as well as suppressing the release of peptides from tumour tissue. The tumours did not grow during treatment. The analogue was well tolerated, most adverse effects being minor. Somatostatin inhibited insulin release, but in only one patient was there a slight deterioration of glucose tolerance. SMS 201-995 is therefore a useful therapeutic tool in the long-term management of patients with symptoms due to uncontrolled hormone secretion from neuroendocrine tumours.

Doxorubicin plus cisplatin in the treatment of apudomas

Twelve patients with advanced apudomas--six with carcinoid tumors, two with chemodectomas, two with pancreatic islet cell tumor, and one each of medullary carcinoma of the thyroid and paraganglioma of unknown primary--were treated with a combination of doxorubicin 50 mg/m2 and cisplatin 50 mg/m2 every 3 to 4 weeks. Biochemical markers were present in 8 of the 12 patients. Five of the 12 patients (3 with carcinoid and 2 with chemodectomas) responded with more than 50% regression of tumor size measured as hypothetical area. Three others (two with islet cell tumors and one with carcinoid) had clinical and/or biochemical improvements. A median duration of response was 6 months. Nausea, vomiting, and alopecia were universal. Mild or moderate leukopenia was the most frequent toxicity. No sustained nephrotoxicity was seen. The combination of doxorubicin and cisplatin provides a new palliative therapy for patients with APUD tumors.

Treatment of patients with pancreatic endocrine tumours using a new long-acting somatostatin analogue symptomatic and peptide responses

Seven patients with gut and pancreatic endocrine tumours have been treated with a long acting somatostatin analogue (SMS 201-995), given as a twice daily subcutaneous injection. This produced dramatic improvement in their endocrine related symptoms, in association with a fall in circulating tumour peptides. One of these patients has now been treated for seven months with this analogue which has controlled his previously life threatening diarrhoea caused by a malignant VIP secreting tumour. He gives his own injections twice daily, and has returned to a full and active life. This is a promising agent both for acute treatment of peptide hypersecretion, and for the long term management of some patients who are unresponsive to other available therapy.

Management of nonfunctioning islet cell tumors of the pancreas

Eleven patients with nonfunctioning islet cell tumor of the pancreas were examined. Since no hypersecretory syndromes were noted, patients' complaints related to enlarging pancreatic masses. Pancreatoduodenectomy was the most commonly performed procedure, with long-term survival of 77 per cent and 62 per cent at two and five years, respectively. Immunohistochemical stains for various polypeptides were positive in two of four tumors tested. Surgical therapy remains the most effective treatment for resectable lesions, with prolonged survival possible in most patients.

Watery diarrhea-hypokalemia-achlorhydria syndrome and carcinoma of the esophagus

The watery diarrhea-hypokalemia-achlorhydria syndrome associated with ectopic secretion of vasoactive intestinal peptide has only been conclusively documented with tumors originating in the pancreas or sympathetic chain. We report here the case of a 50-yr-old woman who developed this syndrome 3 wk after an apparently effective course of radiotherapy for an obstructing, mixed-cell carcinoma of the esophagus. High concentrations of vasoactive intestinal peptide were found in plasma (100-200 pmol/L; normal less than 20 pmol/L) and in the metastatic skin nodules (750 pmol/g) that later developed and that contained one of the two cell types from the original tumor. Stool volumes reached a plateau of 15-20 L/day, and potassium requirements were greater than 1000 mmol/day. Symptoms failed to respond to any of the regimens previously described as effective in this syndrome. After 14 wk of massive fecal fluid and electrolyte losses, symptoms resolved dramatically with the first dose of 5-fluorouracil. Plasma vasoactive intestinal peptide concentration returned to normal, where it remained despite subsequent evidence of renewed tumor spread. This case illustrates the unpredictability of the response of this syndrome to medical treatment, and suggests that vasoactive intestinal peptide secretion may occur in a wider range of tumors than has so far been described.

Content of reports on clinical trials: a critical review

A 10% sample of English language papers, published in 1980, listed in Index Medicus, and classified under the heading, Clinical Trials, was used to assess the state of trials and reports from them. Tabulations are presented concerning the design of the trials represented by the papers in the sample. The manuscript concludes with a discussion of reporting responsibilities for investigators involved in trials and of methods for meeting those responsibilities.

Diabetogenic effect of pentamidine. In vitro and in vivo studies in a patient with malignant insulinoma

Pentamidine can cause hypoglycemia followed by hyperglycemia. The mechanism of this biphasic response is not known but has been reported to be similar to that of streptozotocin and N-3-pyridyl-N-p- nitrourea (Vacor). Pentamidine (4 mg/kg per day for 12 days) was used in a patient with malignant insulinoma after several unsuccessful debulking procedures and chlorozotocin therapy. Mean glucose and immunoreactive insulin levels (+/- SEM) before and after therapy were 80 +/- 40 mg/dl versus 70 +/- 50 mg/dl and 216 +/- 12 microU/ml versus 198 +/- 22 microU/ml, respectively. These were not significantly different. The patient's five-month-old malignant insulinoma monolayer cell culture was incubated with pentamidine (60 micrograms/ml) in the presence or absence of supplemented stimulatory medium consisting of glucose (300 mg/dl) and theophylline (20 micrograms/ml). Chloroquine (60 micrograms/ml) was added to inhibit lysosomal degradation of immunoreactive insulin. Aliquots of media for immunoreactive insulin determination were obtained at 30 minutes, 20 hours, 72 hours, and three weeks. The cells were examined by high-power light microscopy at each time interval. At 30 minutes, pentamidine alone caused passive release of immunoreactive insulin, 23 percent higher than control (p less than 0.01). Stimulatory medium increased immunoreactive insulin 45 percent greater than control (p less than 0.01). Pentamidine plus stimulatory medium had no additive effect on immunoreactive insulin released within 30 minutes. At the end of 20 hours, immunoreactive insulin was no different with pentamidine and/or stimulatory medium. However, the addition of chloroquine increased immunoreactive insulin by 35 percent above the medium with pentamidine and stimulatory medium (p less than 0.01). At 72 hours, pentamidine suppressed immunoreactive insulin by 100 percent in all the media, irrespective of the presence or absence of stimulatory medium and/or chloroquine. At the end of three weeks, there was 50 percent suppression of immunoreactive insulin in the control medium, but pentamidine again completely suppressed immunoreactive insulin. High-power microscopy demonstrated intact cells in the control medium, whereas no cell structure could be detected in the media containing pentamidine at three weeks. In summary, pentamidine had no acute in vivo effect in a patient with malignant insulinoma. However, when used in an in vitro monolayer system, pentamidine caused (1) acute immunoreactive insulin release followed by inhibition of immunoreactive insulin secretion and (2) cytolysis of human malignant insulinoma cells in vitro.

An atypical endocrine tumor of the lung responsive to radiation therapy and 5-fluorouracil-streptozotocin

A case is reported of a patient who presented with a peripheral left upper-lobe lung mass, a thyroid nodule, and multiple enlarged cervical and supraclavicular lymph nodes. Fine-needle aspiration cytology of the lung lesion, the thyroid nodule, and several of the lymph nodes was interpreted as small cell cancer of the lung (SCCL). The patient was treated with Cytoxan (cyclophosphamide), Adriamycin (doxorubicin), and vincristine (CAV), alternating with VP-16 + cisplatin. When progressive disease was documented after three cycles of chemotherapy, an involved cervical lymph node was biopsied. By light microscopy (LM) the tumor appeared to be a poorly differentiated adenocarcinoma, but by transmission electron microscopy (TEM) it was found to have both neuroendocrine and glandular features. Biochemical analysis of the biopsy specimen revealed immunoreactive bombesin, and on immunoperoxidase staining many tumor cells contained neuron-specific enolase. The tumor was therefore classified as an atypical endocrine tumor of the lung (AETL), a recently described morphologic variant for which no therapy has yet been established. The patient was treated with radiation therapy (RT) followed by chemotherapy including 5-fluorouracil (5-FU) (500 mg/m2 IV, d 1-5) and streptozotocin (STZ) (500 mg/m2 IV, d 1-5) every 5-6 weeks, with objective evidence of tumor regression following each modality. This report illustrates the importance of ultrastructural study in the characterization of lung cancer, and indicates the need for the further evaluation of RT and 5FU + STZ in the treatment of neuroendocrine tumors of the lung.

Effect of streptozotocin in a case of glucagon-secreting malignant islets-cell tumor

A case of a 65-year-old woman with a pancreatic tumor secreting insulin, glucagon, and associated with high PTH levels and hypercalcemia is reported. The patient underwent two Streptozotocin (STZ) treatments (1 g iv/week for 10 weeks) after liver metastases were found. Hormonal and metabolic parameters were monitorized . Before the first STZ treatment insulin levels ranged between 78 and 132 microU/ml. After STZ administration insulin decreased and then remained lower (8-48 microU/ml) until the death of the patient. Pre-treatment glucagon levels ranged between 1.3 and 3.9 ng/ml. STZ induced a decrease of glucagon to 0.5 ng/ml. Glucagon chromatography revealed the prevalence of high molecular weight (greater than 6,000 mol wt) immunoreactive glucagon (0.9 ng/ml) drastically reduced by STZ treatment (0.15 ng/ml). Hypoaminoacidemia was observed before STZ administration, but at the end of the therapy plasma amino acid concentrations were normal. Hypercalcemia too was sensitive to STZ, but not PTH value, which remained high. The second STZ treatment performed a year later was less effective and so a chemotherapeutic protocol was started. Our findings suggest a cytolitic effect of STZ on malignant A-cell, with reduction of glucagon levels and restoration of amino acid metabolism. This effect would be useful for medical treatment of non-operable glucagon secreting tumors.

Multiple endocrine neoplasia syndromes

The multiple endocrine neoplasia (MEN) syndromes are characterized by autosomal dominant inheritance with a high degree of penetrance but varying expression. This review gives a classification of these syndromes and a short summary of the historical background. The pathogenesis of the disease and its possible origin in the APUD cell system are discussed together with the mechanisms underlying normal and ectopic hormone production by MEN tumors on the basis of recent findings in molecular endocrinology. The natural history and the clinical manifestations of the different syndromes are described. The sensitivity and discriminative capacity of the tests used to detect the syndromes in an early stage are compared. The choice of therapy and criteria for the timing and extensiveness of treatment are also considered. Lastly, problems associated with the ethical and legal aspects of screening, central registration, and monitoring of relatives at risk are described.

Phase II study of chlorozotocin in islet cell carcinoma. A southwest Oncology Group study

Seventeen patients with islet cell carcinoma received chlorozotocin (CTZ). Nine received 200 mg/m2 IV every 6 weeks and 8 received 100 mg/m2. Responses were seen in eight (2 complete, 5 partial, 1 minor) of 13 patients who had received no prior chemotherapy, and in zero of four who had received prior chemotherapy. Toxicity was mild in most patients and consisted predominantly in myelosuppressions; however, in one patient severe renal failure developed. CTZ may have activity comparable to streptozotocin in this group of patients.

Therapy of malignant APUD cell tumors. Effectiveness of DTIC

Eleven patients with malignant APUD tumors, five islet cell carcinomas, five carcinoid tumors and one medullary carcinoma of the thyroid were treated with DTIC. Nine of 11 patients benefitted from treatment. A literature review revealed that other APUD tumors responded when treated with DTIC. DTIC is a useful agent for treatment of malignant APUDomas, and may be the drug of choice for islet cell carcinoma of the pancreas.

Acute renal failure and renal tubular squamous metaplasia following treatment with streptozotocin

Nephrotoxicity, in the form of transient proteinuria, azotemia, abnormalities of tubular function, and acute renal failure, is the major toxic condition following administration of streptozotocin. The renal morphologic and ultrastructural abnormalities associated with streptozotocin remain poorly defined. We describe a patient with metastatic islet cell tumor of the pancreas who was treated with 16 weekly courses of 1 g/m2 of streptozotocin without marked change in renal function. Following a six-week hiatus without change in renal function, a single course of 1 g/m2 of streptozotocin was administered and resulted in acute renal failure. Light microscopic examination of the kidneys showed irregularly dilated renal tubules lined by low cuboid epithelium. The cells were pleomorphic and showed some mitoses. Nuclei were irregular and variably hyperchromatic. Electron microscopic examination disclosed large aggregates of fine microfilaments in the proximal convoluted tubules and collecting ducts. Microfilament aggregates were both free in the cytoplasm and membrane bound. Microfilaments were proved to be tonofilaments by the demonstration of keratin within the epithelium, using the immunoperoxidase method. These data suggest that squamous metaplasia may be an important part of streptozotocin renal toxicity, and the suggestion is made that they may be an antecedent of neoplastic change.

Clinicopathological study of pancreatic and ganglioneuroblastoma tumours secreting vasoactive intestinal polypeptide (vipomas)

During a six-year period (1973-9) 52 patients with pancreatic tumours and 10 with ganglioneuroblastomas were found to have raised plasma vasoactive intestinal polypeptide (VIP) concentrations. All the patients had severe secretory diarrhoea, weight loss, dehydration, hypokalaemic acidosis, and a raised plasma urea concentration. Reduced gastric acid secretion was seen in 72% of patients. Plasma VIP concentrations were not raised in patients with diarrhoea due to other types of tumour or disease or in hormone-secreting tumours not associated with diarrhoea. Plasma VIP measurement may therefore give clinical guidance in a patient with persistent watery diarrhoea and hypokalaemic acidosis. Surgical excision was clearly the treatment of choice, but metastatic pancreatic tumours usually responded to streptozotocin.