Nuclear medicine in the detection, staging and treatment of gastrointestinal carcinoid tumours

Carcinoid of the ampulla of Vater: Morphologic features and clinical implications

Carcinoids involving the ampulla of Vater are rare lesions that may produce painless jaundice. The published data indicate that these tumors, in contrast to their midgut counterparts, metastasize in approximately half of cases irrespective of primary tumor size. Therefore, radical excision in the form of pancreaticoduodenectomy is recommended regardless of tumor size. As with other gastrointestinal carcinoid tumors, biological treatment with octreotide analogues can be applied to symptomatic patients. Tumor-targeted radioactive therapy is a newly emerging treatment option. We here report case of a carcinoid tumor of the ampulla of Vater presenting as painless jaundice in a 65-year old man and review the relevant literature, giving special attention to the morphologic features, clinical characteristics, and treatment modalities associated with this disease process.

Peritoneal carcinomatosis from a small bowel carcinoid tumour

BACKGROUND

Peritoneal carcinomatosis from a gastrointestinal carcinoid tumour is rare and the long-term management and prognosis have not been clearly defined. The natural history is different from gastrointestinal adenocarcinoma, although its capacity to invade regional lymph nodes and generate distal metastasis can make the management more complex. Whilst the development of carcinomatosis is uncommonly reported, it may be higher than expected.

CASE PRESENTATION

A 63 years-old woman underwent emergency surgery in 1993 for right iliac fossa pain and a mass that was found to be an ileal carcinoid tumour. Over the next ten years, further surgery was required for disseminated disease with peritoneal carcinomatosis and liver metastasis. Systemic chemotherapy had little effect, although Somatostatin was used effectively to relieve symptoms caused by the disseminated disease (flushing and diarrhoea).

CONCLUSION

Peritoneal carcinomatosis from carcinoid tumours is not well documented in the literature. Aggressive surgery must be performed in order to control the disease since chemotherapy has not been reported to be effective. With repeated surgery long-term survival can be achieved in these patients.

Review article: Pathogenesis and management of gastric carcinoid tumours

BACKGROUND

Gastric carcinoid tumours are rare, but are increasing in incidence.

AIM

To discuss tumour pathogenesis and outline current approaches to patient management.

METHODS

Review of published articles following a Pubmed search.

RESULTS

Although interest in gastric carcinoids has increased since it was recognized that they are associated with achlorhydria, to date there is no definite evidence that humans taking long-term acid suppressing medication are at increased risk. Type I tumours are associated with autoimmune atrophic gastritis and hypergastrinaemia, type II are associated with Zollinger-Ellison syndrome, multiple endocrine neoplasia-1 and hypergastrinaemia and sporadic type III carcinoids are gastrin-independent and carry the worst prognosis. Careful investigation of these patients is required, particularly to identify the tumour type, the source of hypergastrinaemia and the presence of metastases. Treatment can be directed at the source of hypergastrinaemia if type I or II tumours are still gastrin responsive and not growing autonomously. Type III tumours should be treated surgically.

CONCLUSIONS

Advances in our understanding of the pathogenesis of gastric carcinoids have led to recent improvements in investigation and management. Challenges remain in identifying the genetic and environmental factors, in addition to hypergastrinaemia, that are responsible for tumour development in susceptible patients.

[Bronchial and appendiceal carcinoid tumors]

BACKGROUND

Carcinoid tumor (CT) is an unusual neoplasm observed in several locations and associated with the production of vasoactive substances and occasionally with carcinoid syndrome (flushing, diarrhea, wheezing).

PATIENTS AND METHODS

A retrospective review of the medial records of all children with a diagnosis of CT treated in our service between 1966 and 2003 was performed.

RESULTS

Ten patients (5 boys and 5 girls with a mean age of 8 years) were diagnosed with CT. Eight had CT of the appendix, of which 4 showed the typical clinical presentation of acute appendicitis. Seven of these tumors were localized at the tip of the appendix and measured 2 cm or less. In one patient, the tumor was located at the cecum and measured 3.5 cm. In this patient, reoperation with ileocecal resection was performed. Two patients (4 and 6 years old) had bronchial CT associated with chronic respiratory manifestations. An accurate diagnosis was made after a 1-year follow-up. Pneumonectomy and tracheobronchial sleeve resection were carried out. None of the patients showed symptoms of carcinoid syndrome. All the patients underwent biochemical and radiological studies and fiberoptic bronchoscopy during follow-up. All the patients are currently disease-free.

CONCLUSIONS

Typical symptoms of acute appendicitis were not observed in half of patients with CT of the appendix. CT associated with carcinoid syndrome is exceptional in pediatric patients. In most CT of the appendix, simple appendicectomy was associated with an excellent prognosis. Diagnosis of bronchial TC tends to be delayed and consequently CT should be considered in the differential diagnosis of children with respiratory symptoms unresponsive to standard medical treatment.

A complex case of rectal neuroendocrine carcinoma with terminal delirium

BACKGROUND

A 62-year-old white male presented to our department in December 2004 with a 1-month history of intermittent, voluminous bleedings per rectum. His medical history was unremarkable apart from a single, short-lasting syncope shortly before the first bleeding episode.

INVESTIGATIONS

Physical examination, colonoscopy, rectal tumor biopsy and immunohistochemistry, pelvic MRI, abdominal and chest CT scans, ultrasound-directed puncture cytology, octreotide scintigraphy, biochemical analysis of tumor markers, and conventional laboratory tests.

DIAGNOSIS

Locally advanced rectal neuroendocrine carcinoma with liver metastases.

MANAGEMENT

Chemotherapy, CT-planned radiotherapy, antihypercalcemic therapy, terminal supportive care.

Gastrointestinal carcinoids: the evolution of diagnostic strategies

Carcinoid tumors are rare, often insidious neoplasms arising from neuroendocrine cells. The majority arise in the gastrointestinal system, and are often incidentally found during investigation, although some may present as an emergency bleed or perforation. The prosaic symptoms of flushing, diarrhea, and sweating are often overlooked; thus, the diagnosis is usually much delayed and the tumor is advanced at presentation. This diagnostic delay renders effective management difficult and adversely affects outcome. This overview provides a current assessment of the evolution of the diagnostic techniques available to establish an accurate biochemical (5-hydroxyindole-3-acetic acid and chromogranin A) and topographic diagnosis (octreoscan, radio-labeled metaidobenzylguanidine, computerized tomography, magnetic resonance imaging, positron emission tomography, enteroclysis, endoscopic ultrasound, enteroscopy, capsule endoscopy, and angiography) of carcinoid tumors. The utility and shortcomings of the respective modalities available are evaluated. Although considerable advances have been made in establishing the diagnosis of carcinoid tumors and in defining the topography of metastatic disease, the major limitation is the inability to establish an early and timely diagnosis before the advent of metastatic disease.

Catecholamine-Secreting Metastatic Carcinoid as Differential Diagnosis in Pheochromocytoma: Clinical, Laboratory, and Imaging Clues in the Search for the Lurking Neuroendocrine Tumor (NET)

Catecholamine-secreting metastatic carcinoid should be considered in differential diagnosis of malignant pheochromocytoma. Paroxysmal functioning or hormonally silent gastroenteropancreatic neuroendocrine tumors (GEP NETs) require repeat biochemical measurements and sensitive anatomic and functional imaging studies overlapping those for malignant pheochromocytoma. This report presents clinical, laboratory, and radiologic findings in a patient presenting with heart rate variability; vasoactive headaches reactive to ethanol, tyramine and tryptophan; labile blood pressure; diaphoresis; diarrhea; abdominal pain; unexplained pancreatitis; joint pain; and paroxysmal flushing with pallor. GI studies (including endoscopic ultrasound) and multiple imaging modalities (including 2D CT, MRI with gadolinium, [18]FDG PET/CT, [123I]MIBG, and SRS [111In]Octreotide [OctreoScan]) were not diagnostic. 24-h BP, Holter and 30-day cardiac event monitors plus urinary biochemical studies consistently suggested catecholamine-synthesizing NET. NIH plasma metanephrines studies and [6]-[18F]Fluorodopamine PET ruled out malignant pheochromocytoma (pheo). Repeated studies showed persistently abnormal GEP NET biomarkers and urinary catecholamines. Capsule endoscopy revealed suspicious submucosal lesions throughout the small intestine. Dual-phase 64-slice multidetector computed tomography (MDCT) with 3D volumetric reconstruction of the abdomen and pelvis revealed multiple diffuse liver metastases and three extrahepatic lesions consistent with metastatic carcinoid. In combination, intensive biochemical testing repeated over time, dual-phase 64-slice MDCT with 3D image reconstruction and volume-rendering (VR) technique, and advanced radionuclide imaging are required to detect NETs' sporadic or paroxysmal functioning, rule out extra-adrenal pheochromocytoma, and localize and characterize metastatic carcinoid. If pheochromocytoma is ruled out, yet symptoms and biochemical markers for catecholamine excess are present, then carcinoid and other amine-precursor-uptake decarboxylation (APUD) tumors must remain in the differential diagnosis.

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 advanced carcinoid tumors

PURPOSE OF REVIEW

Carcinoid tumors often present with metastatic disease. Generally, these tumors can be treated conservatively. New evidence exists, however, that stage IV disease may be better managed with more aggressive medical and surgical treatment. Headway is also being made into understanding the associated fibrosis seen with advanced disease and in better understanding signaling pathways with the hope of offering future treatment options.

RECENT FINDINGS

Recent literature has advocated for more aggressive surgical treatment of carcinoid tumors, especially in the setting of hepatic metastases and peritoneal carcinomatosis. Octreotide and lanreotide are further being described for treating metastatic carcinoids. Radiolabeled somatostatin analogues may prove to be as effective for treating carcinoids as for visualizing them. Other potential treatment modalities include pharmacologic activation of signaling pathways to control excess hormone production. Research into fibrosis - a cause of pain, bowel obstruction, retroperitoneal vascular constriction and right heart failure - has shown that serotonin and tachykinins may be the key mediators.

SUMMARY

Patients with stage IV carcinoid tumors may benefit from more aggressive surgical management and new treatment modalities. The growing body of knowledge regarding important molecular signaling pathway may lead to new medical therapies and further understanding of the sequelae of excess hormone production.

Advances in alimentary tract imaging

Advances in imaging techniques are changing the way radiologists undertake imaging of the gastrointestinal tract and their ability to answer questions posed by surgeons. In this paper we discuss the technological improvements of imaging studies that have occurred in the last few years and how these help to better diagnosing alimentary tract disease.

99mTc-EDDA/HYNIC-octreotate scintigraphy, an efficient method for the detection and staging of carcinoid tumours: results of 3 years’ experience

PURPOSE

At all stages of the disease, serious difficulties are encountered in the imaging diagnosis of carcinoids. Somatostatin receptor scintigraphy (SRS) holds great promise for detecting primary tumours and metastases. 99mTc-EDDA/HYNIC-octreotate should significantly improve the diagnosis of carcinoids in comparison with 111In-Octreoscan owing to the better affinity for SSR2 and the higher count rate. The aim of this study was to assess the diagnostic efficiency of 99mTc-EDDA/HYNIC-octreotate scintigraphy in the detection and staging of carcinoid tumours.

METHODS

The study population comprised 75 patients (age 48.5+/-15.5 years): 46 with histological confirmation of carcinoid and 29 with suspected disease. 99mTc-EDDA/HYNIC-octreotate (740 MBq) SRS and CT were performed in all patients. Fifteen patients were examined with 111In-Octreoscan.

RESULTS

High-quality 99mTc-EDDA/HYNIC-octreotate images were obtained in all cases, with maximum tumour tracer accumulation 4 h p.i. The mean target/non-target ratios for whole body (WB) and SPECT scans were, respectively, as follows: primary lesions: 4.5 and 10.2; metastases: liver, 3.1 and 12.3; abdominal focal lesions, 2.7 and 5.8; lung, 2.7 and 8.3; mediastinum, 3.4 and 7.6; bones, 6.8 and 19.0. 99mTc-EDDA/HYNIC-octreotate WB scans revealed more metastases than 111In-Octreoscan, with better individual separation. 99mTc-EDDA/HYNIC-octreotate SRS revealed new metastatic lesions in seven patients with confirmed carcinoid, and in four with dissemination the primary focus was found. Five patients qualified for radioguided surgery and 11 were referred to 90Y-DOTA-TATE therapy. The sensitivity of SRS in comparison with CT was higher for primary lesions and liver and abdominal lymph node metastases. In the subgroup of patients with suspected neuroendocrine tumours, two duodenal carcinoids, one thymic carcinoid and one ileal carcinoid were found.

CONCLUSION

99mTc-EDDA/HYNIC-octreotate, with high imaging quality, is an excellent alternative to 111In-Octreoscan for staging of carcinoids, and it seems to be the method of choice for detection of the primary focus in patients with metastases from an unknown primary tumour.

Therapeutic options for gastrointestinal carcinoids

Although wide surgical resection is the optimal curative therapy for carcinoid tumors, in most patients the presence of metastatic disease at diagnosis usually renders excision a palliative procedure. This nevertheless decreases tumor burden, facilitates symptom control, and prevents complications caused by bleeding, perforation, or bowel obstruction resulting from fibrosis. In the stomach (types I and II) and rectum endoscopic excision may be adequate provided the lesion(s) are local. Long-term therapy is focused on symptom alleviation and improvement of quality of life using somatostatin analogues, particularly in a subcutaneous depot formulation. In some instances interferons may have a role but their usage often is associated with substantial adverse events. Conventional chemotherapy and external radiotherapy either alone or in a variety of permutations are of minimal efficacy and should be balanced against the decrease in quality of life often engendered by such agents. Hepatic metastases may be amenable to surgery, radiofrequency ablation, or embolization either alone or in combination with chemotherapeutic agents or isotopically loaded microspheres. Rarely hepatic transplantation may be of benefit although controversy exists as to its actual use. Peptide-receptor-targeted radiotherapy for advanced disease using radiolabeled octapeptide analogs (111In/90Yt/177Lu-octreotide) appear promising but data are limited and its status remains investigational. A variety of antiangiogenesis and growth factor-targeted agents have been evaluated, but as yet have shown little promise. The keystone of current therapy remains the long-acting somatostatin analogues that alleviate symptomatology and substantially improve quality of life with minimal adverse effects.

Liver resection for primary hepatic neuroendocrine tumours: report of three cases and review of the literature

Primary neuroendocrine tumours are rare especially in the liver, which is more often site of metastatic tumours. We report three cases of primary hepatic neuroendocrine tumours, which underwent hepatic resection. Review of the diagnostic and therapeutic approaches to these tumours are discussed.