Method for dissection of mesenteric metastases in mid-gut carcinoid tumors

GI carcinoid tumours: appearance of the primary and detecting metastases

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

Current status of gastrointestinal carcinoids

Gastrointestinal (GI) carcinoids are ill-understood, enigmatic malignancies, which, although slow growing compared with adenocarcinomas, can behave aggressively. Carcinoids are classified based on organ site and cell of origin and occur most frequently in the GI (67%) where they are most common in small intestine (25%), appendix (12%), and rectum (14%). Local manifestations--mass, bleeding, obstruction, or perforation--reflect invasion or tumor-induced fibrosis and often result in incidental detection at emergency surgery. Symptoms are protean (flushing, sweating, diarrhea, bronchospasm), usually misdiagnosed, and reflect secretion of diverse amines and peptides. Biochemical diagnosis is established by elevation of plasma chromogranin A (CgA), serotonin, or urinary 5-hydroxyindoleacetic acid (5-HIAA), while topographic localization is by Octreoscan, computerized axial tomography (CAT) scan, or endoscopy/ultrasound. Histological identification is confirmed by CgA and synaptophysin immunohistochemistry. Primary therapy is surgical excision to avert local manifestations and decrease hormone secretion. Hepatic metastases may be amenable to cytoreduction, radiofrequency ablation, embolization alone, or with cytotoxics. Hepatic transplantation may rarely be beneficial. Chemotherapy and radiotherapy have minimal efficacy and substantially decrease quality of life. Intravenously administered receptor-targeted radiolabeled somatostatin analogs are of use in disseminated disease. Local endoscopic excision for gastric (type I and II) and rectal carcinoids may be adequate. Somatostatin analogues provide the most effective symptomatic therapy, although interferon has some utility. Overall 5-year survival for carcinoids of the appendix is 98%, gastric (types I/II) is 81%, rectum is 87%, small intestinal is 60%, colonic carcinoids is 62%, and gastric type III/IV is 33%.

Management of midgut carcinoids

Midgut carcinoids developing in the small intestine represent the most common cause of the carcinoid syndrome, with severe symptoms of flush, diarrhoea, and fibrotic valvular heart disease. The tumours may be histologically identified with specific chromogranin A or synaptophysine immunostainings, and by serotonin reactivity, which supports a midgut origin. Urinary 5-HIAA excretion and serum chromogranin A measurements are used as biochemical tumour markers for clinical diagnosis, and as important monitors of treatment effects and prognostic predictors. The midgut carcinoids have typically slow proliferation and extended disease course, and surgical treatment has become increasingly important for their management. Surgery should aim to remove primary tumours and mesenteric metastases, which may cause long-term abdominal complications, by typical fibrotic intestinal entrapment and small bowel ischaemia due to encasement of mesenteric vessels. Attempts should also be made to surgically remove or ablate liver metastases, since this may significantly contribute to palliation of the carcinoid syndrome. In patients with this syndrome surgery is combined with continuous biotherapy with long-acting somatostatin analogues and interferon, which may alleviate symptoms and cause stable disease with slow progression. Favourable survival and life-quality can be expected with this treatment also in patients with advanced midgut carcinoids.

Prise en charge chirurgicale des tumeurs endocrines du tractus gastro-intestinal

Surgical management of gastro-intestinal endocrine tumors has to be adapted to tumor localization and disease extension (local and general). The aim of this literature review was to define surgical management of these unfrequent tumors.

Carcinoid tumors and fibrosis: an association with no explanation

Carcinoid tumors are slow-growing neuroendocrine neoplasms most commonly associated with the gut and broncho-pulmonary system. In many instances, they are identified at surgery for unexplained bowel obstruction or during exploration of the small bowel in search of a primary tumor once distant metastases have been detected. Carcinoid tumors of the small bowel often present with pronounced fibrosis in the peri-tumoral tissues, distant in the heart or lungs, and locally in the peritoneal cavity. Despite medical and therapeutic advances that have alleviated symptoms and prolonged life, a substantial subset of patients develops mesenteric and small bowel carcinoid fibrosis and/or carcinoid heart disease. Fibrosis, and increasingly cardiac heart disease, are important components of intestinal carcinoid disease and are of considerable clinical concern, as both of these conditions reflect a connective tissue disorder whose etiology, biology, and therapy are unknown. In the past, individuals with carcinoid disease died of metastasis and uncontrollable symptomatology. Currently, there exists no clinical method to determine the development of fibrosis and little is understood about the biological basis of fibrosis. The elucidation of the biology and management of fibrosis is thus an issue of paramount clinical and scientific importance in determining appropriate diagnostic and therapeutic strategy. Therefore, the unraveling of the molecular events indicative of fibrosis in these cells and the identification of appropriate therapeutic targets is of considerable patient-care relevance. We have surveyed the world literature over the past 40 yr to evaluate both the incidence of carcinoid processes and track the evolving understanding of this process. In addition, we have provided more current mechanistic information in regard to the biological basis of fibrosis associated with small bowel carcinoid tumors.

Complications of midgut carcinoid tumors and carcinoid syndrome

The carcinoid syndrome, associated with carcinoid tumors of the midgut, consists of symptoms such as diarrhea, flushing, wheezing and cardiovascular symptoms. This review focuses on these symptoms and discusses therapeutic options. The symptoms are caused by the secretion of biogenic amines, polypeptides and other factors of which serotonin is the most prominent. However, diarrhea is also due to factors such as malabsorption. Besides antitumor therapy, more specific interventions such as serotonin receptor blockers can be useful. The carcinoid heart disease involves the tricuspid and pulmonary valve. In the pathogenesis, serotonin plays a central role. The therapeutic approach is mostly symptomatic. Other cardiovascular complications include bowel ischemia and hypertension. Pellagra and psychiatric symptoms are due to a depletion of tryptophan, which is consumed by the carcinoid tumor for serotonin synthesis. Finally, follow-up and clinical practice of patients with carcinoid tumors are discussed.

Surgery for carcinoid tumours of the lower gastrointestinal tract

INTRODUCTION

Carcinoid tumours are rare neoplasms that originate from neuroendocrine cells of the primitive gastrointestinal tract. Mid- and hind-gut tumours comprise the majority of these rare tumours. With many recent advances in medical treatment the role and importance of surgery and the surgeon needs to be assessed.

METHOD

A Medline, Pubmed and Embase databases search was undertaken. All relevant articles were cross-referenced.

RESULTS AND CONCLUSIONS

Incidental findings of carcinoid tumours should be treated at initial surgery whilst elective surgery and further management should be undertaken in specialist centres by a multidisciplinary team. Asymptomatic patients have a better prognosis than those with symptoms. In advanced cases surgery combined with chemotherapy and liver resection is appropriate. The outlook for the majority of cases is good.

Cytoreductive Surgery in Patients with Advanced-Stage Carcinoid Tumors

The role of aggressive surgical resections as well as criteria for resectability in patients with advanced carcinoid tumors is not clearly defined. Thirty patients (17 male and 13 female) who were previously diagnosed to have “unresectable carcinoid disease” were treated using a multi-modality approach over a period of 2 years. Extensive liver involvement was present in 28 of 30 (93%) of the cases. Small bowel involvement was noted in 22 of 30 (73%), and peritoneal/retroperitoneal/mesenteric invasion was observed in 15 of 30 (50%) of the cases. Three patients had remote metastases (brain, bone, and eye). Twenty of 30 (66%) patients had carcinoid syndrome with severely disabling symptoms. Eight patients (26%) had small bowel obstruction. All patients underwent at least one surgical exploration/intervention. Radiofrequency ablation (RFA) of one or more liver lesions was performed as an adjunct in 22 of 30 (73%) patients. Six patients (20%) had a second surgical procedure. There were 11 complications in eight patients (27%) after the initial operation. Median hospital stay for patients who underwent RFA only, RFA/liver resection, and liver resection with abdominal tumor debulking were 2,4, 8, and 16 days respectively. Twenty-five of 30 patients (83%) showed symptomatic improvement. Mean pre- and postoperative Karnofsky physical performance scores were 55 and 85 respectively ( P < 0.02). Small bowel obstruction was due to adhesions in five patients. All patients with intestinal obstruction had complete relief of their symptoms postoperatively. 5-Hydroxyindolacetic acid levels decreased by 50 per cent in all patients with follow-up determinations available. Aggressive surgical exploration and tumor debulking could be performed with significantly improved symptomatic outcome and relatively minor complications. Longer follow-up is needed for assessment of effect on survival.

Diagnostic, surgical and medical aspect of the midgut carcinoids

This review covers the incidence, prognosis, diagnosis and treatment of midgut carcinoids with emphasis on the surgical and peri-operative aspects. Midgut carcinoids are rare neuro-endocrine tumours which become manifest once they have metastasized to the liver. Treatment of metastatic disease may include radical resection but is usually palliative. The tumour grows relatively slow. Besides the biochemical effects resulting in the carcinoid syndrome, patients may suffer from mechanical mass effects of the tumour. Medical treatment can alleviate the biochemical effects of the tumour, but has a limited effect on tumour growth. The introduction of octreotide was a milestone in palliation of these symptoms and has led to more aggressive treatment protocols. Treatment aimed at cytoreduction of hepatic metastasis and diminished secretion of bioactive amines may achieve good palliation. Cytoreduction may be performed by means of surgery, hepatic arterial ligation, (chemo)embolization, cryosurgery, radio-frequency ablation, internal radiation or even liver transplantation. The role of these options will be discussed in this review.

Carcinoid tumors: molecular genetics, tumor biology, and update of diagnosis and treatment

Carcinoid tumors are rare neoplasms which, by tradition, have been divided into foregut, midgut, and hindgut tumors. Although they share many features, they seem to have different molecular backgrounds. Foregut tumors very often show involvement of the MEN1 gene with deletions and mutations, whereas midgut carcinoids display genetic changes on chromosome 18. Hindgut tumors in general show rather low proliferation capacity, and transforming growth factor-alpha/epidermal growth factor receptor autocrine mechanism may play a role in the tumor development. Sometimes it might be a problem to delineate the location of the primary carcinoid tumor, but analyzing thyroid transcription factor-1 can be of help, because this factor is only expressed in foregut carcinoid and not in midgut or hindgut tumors. Chromogranin A is an important general tumor marker for all types of carcinoid tumors. Somatostatin receptor scintigraphy is a cornerstone in staging and localization of carcinoid tumors, but newer techniques such as positron emission tomography will challenge its position in the future. Although surgical cure is not obtainable, a more aggressive surgery has emerged during the last decade. Debulking and other cytoreductive procedures are quite common today. Somatostatin analogues have been the treatment of choice in symptomatic patients with carcinoid tumors, but more recent studies have indicated a cytostatic effect of somatostatin analogues. Tumor-targeted radioactive treatment based on somatostatin analogues is now under clinical evaluation. Preliminary data indicate interesting clinical potentials.