Carcinoid tumours

Skeletal metastasis of carcinoid tumors: Two case reports and review of the literature

Carcinoid tumors are neuroendocrine neoplasms derived from enterochromaffin cells. Skeletal metastases from carcinoid tumors are considered to be extremely rare. In this study, we present two cases of carcinoid tumors that metastasized to the bone. Furthermore, we review 50 published case reports and reveal the features of skeletal metastasis of carcinoid tumors. The first case involved a 59-year-old man with a history of multiple metastases of a lung carcinoid tumor. The patient complained of back pain and numbness in the lower limbs. Magnetic resonance imaging revealed metastases in the thoracic spine. A spinal decompression was performed and the symptoms were resolved. The second case involved a 74-year-old man had been diagnosed with a lung carcinoid tumor 15 years previously and complained of left thigh pain. A radiograph showed osteolytic lesions in the shaft of the left femur. We repaired the femur using an intramedullary nail following curettage of the tumor. A radiograph of the femur revealed a callus on the pathological fracture. The patient was able to walk using a crutch 3 months after surgery. We reviewed 50 cases that described skeletal metastasis from carcinoid tumors. The average age of the patients was 54.9 years and 33 patients (66%) were male. The most common site of skeletal metastasis was the spine. We also investigated the survival rate of patients who developed skeletal metastasis from carcinoid tumors. The findings showed that survival of patients who developed osteolytic skeletal metastasis was worse than that of patients who developed osteosclerotic skeletal metastasis.

From somatostatin to octreotide LAR: evolution of a somatostatin analogue

BACKGROUND

Acromegaly is characterized by overproduction of growth hormone (GH) by the pituitary gland. GH stimulates the synthesis of insulin-like growth factor-I (IGF-I), and the somatic growth and metabolic dysfunction that characterize acromegaly are a consequence of elevated GH and IGF-I levels. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are rare, slow-growing neoplasms that have usually metastasized by the time of diagnosis. The majority of GEP-NETs are carcinoid tumors whose syndrome is caused by the hypersecretion of biogenic amines, peptides and polypeptides responsible for the principal symptoms of diarrhea and flushing.

METHODS

The MEDLINE and EMBASE databases were searched for preclinical and clinical studies of octreotide (Sandostatin* ), a potent synthetic somatostatin analogue, in patients with acromegaly or GEP-NETs.

OBJECTIVE

This article reviews the 20 years of clinical experience with octreotide and the impact it has made in patients with acromegaly or GEP-NETs.

RESULTS

Octreotide has proven to be an essential component in the management strategy of acromegaly and GEP-NETs over the past 20 years. The multiple beneficial effects of octreotide throughout the body, combined with its established safety profile (the most common adverse effects are injection-site pain and gastrointestinal events), have made it an appealing option for clinicians. The advent of the long-acting release (LAR) formulation of octreotide provided additional benefits to patients through monthly administration, while maintaining the efficacy and tolerability profile of the daily subcutaneous formulation.

CONCLUSIONS

Octreotide is a potent synthetic somatostatin analogue that has become the mainstay of medical therapy for tumor control in neuroendocrine disorders such as acromegaly and GEP-NETs. The development of octreotide LAR offered a further advancement; less frequent dosing provided valuable benefits in quality of life to patients, with equivalent efficacy and tolerability. Moreover, recent results from the PROMID study have confirmed the antiproliferative effect of octreotide LAR in patients with well-differentiated metastatic GEP-NETs of the midgut. New therapeutic uses of octreotide are currently under investigation in a variety of clinical settings.

[Gastrointestinal carcinoid tumors: cellular biology, molecular expression and physiopathological consequences of an enigmatic neoplasia]

Gastrointestinal carcinoid tumors arise from cells of the diffuse neuroendocrine system localized in the digestive trace and represent more than 70% of all carcinoid tumors in humans. The present article reviews the following topics: 1) The biological profile of these tumors (histopathology, cytokine markers, metabolic alterations, storage of neuroamines and hormonal proteins, cytodynamic behavior, and biological behavior according to embryological origin). 2) The etiological circumstances (exceptional hereditary factors, association of gastric carcinoid tumors with autoimmune gastritis, little-known exogenous factors). 3) Pathogenic aspects (persistent mitogenesis of endocrine cells associated with hypergastrinemia, inactivation of some putative tumor suppressor genes, the doubtful participation of oncogenes, autocrine action of some cellular growth-stimulating proteins). 4) The repercussions of certain physiopathological events (peritumoral desmoplastic reaction causing the "mass effect" on the digestive tube, the "kidnapping" of dietary tryptophan by tumoral cells toward an abnormal metabolic pathway; the easy metastatic dissemination coexisting with low tumoral aggressivity, and the release into the bloodstream of stored secretory products leading to "carcinoid syndrome" and some endocrine hyperfunction syndromes. Finally, it should be remembered that gastrointestinal carcinoid tumors represent only a proportion of the neoplasms classified as neuroendocrine tumors.

The neuroendocrine tumors of the ileum

Neuroendocrine tumors arise from the diffuse neuroendocrine system and secrete several peptides and bioactive amines (serotonin, histamine, dopamine, norepinephrine, corticotropin, calcitonin, bradykinin, kalikrein, gastrin, cholecystokinin, prostaglandins). The most common occurrence site of neuroendocrine tumors is the ileum. The symptoms of small bowel carcinoids are represented by intermittent intestinal obstruction and carcinoid syndrome. Presence of the carcinoid syndrome usually indicates hepatic or retroperitoneal metastases. The typical carcinoid syndrome is characterized by flushing, diarrhea, nonspecific abdominal pain and bronchospasm. The diagnosis of small bowel tumors is often difficult due to their rarity and the nonspecific and variable nature of the presenting signs and symptoms. The most useful initial diagnostic test for the carcinoid syndrome is to measure 24-hour urinary excretion of 5-hydroxyindolacetic acid (5 HIAA), which is the end product of serotonin metabolism. Capsule endoscopy is a more recent diagnostic tool. Surgery is the radical form of curative therapy for carcinoid tumors. Numerous therapies are available for palliation including surgery, pharmacologic therapy, interventional radiologic therapy, embolization and chemoembolization of hepatic metastases, immunotherapy (Interferon alfa) and chemotherapy. We carefully reviewed the available literature on this topic before beginning our study.

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.

Carcinoid--a comprehensive review

Carcinoid tumors originate from the neuroendocrine cells throughout the body and are capable of producing various peptides. Their clinical course is often indolent but can also be aggressive and resistant to therapy. We examined all aspects of carcinoid tumors including the molecular biology oncogenesis, role of angiogenesis, recent advances in imaging, and therapy. The Medline and Cancerlit databases were searched using carcinoid as the keyword. English language manuscripts were reviewed and relevant references from a total of 7741 were found. All titles were screened and all the relevant manuscripts were analyzed; we found 307 references pertinent to the history, epidemiology, clinical behavior, pathology, pathophysiology, molecular biology, radiologic imaging, supportive care of carcinoid syndrome, and results of therapeutic clinical trials. Management of patients with carcinoid tumors requires an understanding of the disease process and a multimodality approach. Introduction of long-acting somatostatin analogues has resulted in significant advances in the palliative care of patients with carcinoid syndrome. However, advanced carcinoid tumor remains incurable. Existing therapies for advanced disease have low biologic activity, high toxicity, or both. Clearly, more research is necessary in the areas of molecular biology, targeted therapy, and development of new drugs Future advances in this field need to focus on clinical and biological predictors of outcome. Early works in the area of tumor biology such as the role of p53, bcl-2, bax, MEN1, FGF TGF PDGF and VEGF expression are of interest and need to be explored further.

(131)I-MIBG radionuclide therapy is safe and cost-effective in the control of symptoms of the carcinoid syndrome

BACKGROUND

The standard treatment used to control the symptoms of carcinoid syndrome (CS) involves subcutaneous injections of the somatostatin analogue octreotide. This is expensive (US $8000--16,000 per year), and treatment may be for many years. The aim of this study was to evaluate the efficacy and cost-effectiveness of our experience over the last 5 years with 1-131-labelled metaiodobenzylguanidine (MIBG) radionuclide therapy in the palliation of patients with CS.

METHODS

A consecutive series of 20 symptomatic patients (referred between 1994 and 1999) with CS were evaluated. Fifteen of them underwent(123)I-MIBG scanning. Of the 13 patients with significant tracer uptake in metastatic deposits compared to background, 12 underwent a course of therapeutic(131)I-MIBG (one patient refused). Symptoms, biochemical markers, CT scans, follow-up(123)I-MIBG scans, and the requirement for octreotide were used to assess outcome of treatment. Costs of(131)I-MIBG and octreotide treatments were compared.

RESULTS

MIBG treatment was well tolerated in all with only transient side-effects. Ten patients showed a measurable clinical improvement. Seven had a complete clinical response. The mean duration of response was 15.4 months. Octreotide was not required or was reduced in eight patients. Treatment with(131)I-MIBG resulted in a saving of US $1000 per patient, with effective symptom control, when compared to octreotide.

CONCLUSION

1-131 MIBG therapy is a safe and cost-effective therapeutic option to successfully control symptoms in patients with carcinoid syndrome.

Complete histological regression of metastatic carcinoid tumour after treatment with octreotide

A 69-year-old woman was admitted with facial flushing, weight loss and intermittent diarrhoea. Urinary 5-hydroxyindole-acetic acid (5-HIAA) level was elevated at 200 micromol/24 h (normal: < 50). Computerized tomography (CT) demonstrated multiple enhancing liver metastases with biopsy proven carcinoid metastases with no evidence of primary tumour at this stage. Octreotide was initiated, resulting in marked improvement in carcinoid symptoms. Nine years later, she presented with abdominal pain and slightly deranged liver function tests. Repeat colonoscopy at this stage, showed an ileal tumour causing impending obstruction, necessitating urgent right hemicolectomy. Histology demonstrated primary carcinoid tumour. She continued on octreotide. Three years later at the age of 81 years, she suffered a fatal haemorrhagic stroke. Autopsy revealed complete regression of hepatic carcinoid metastases.

Carcinoid Heart Disease

Carcinoid syndrome originates from metastatic carcinoid tumors localized in the gastrointestinal system, pancreas, biliary vessels, bronchi, ovaries, and testes; it is characterized by flushing, telangiectasias, diarrhea, bronchoconstriction, and fibrous endocardial plaques in the heart. Cardiac involvement is detected by echocardiography in over 50% of patients with this syndrome. Right-sided valvular heart disease occurs frequently in patients with carcinoid syndrome, involving most commonly the tricuspid and pulmonary valves. Involvement of the left-sided valves rarely occurs. Medical therapy for carcinoid heart disease includes digitalis and diuretics for congestive heart failure symptoms; the effects of carcinoid syndrome can be treated with the use of somatostatin analogues. Conventional chemotherapy has been of little beneficial value, with response rates of only 10% to 30%. The use of octreotide, a long-acting and potent somatostatin analogue, is a major advance in the management of carcinoid tumors. In addition to providing effective symptom relief in malignant carcinoid syndrome, octreotide can also be used for diagnostic purposes. Despite its expense, octreotide is the current agent of choice for the treatment of this condition. Analogues with different receptor specificities and pharmacokinetics hold promise for the future. Valve surgery is the only definitive treatment for intractable right-sided heart failure. Although cardiac surgery carries high perioperative mortality, marked symptomatic improvement occurs in survivors. Surgical intervention therefore should be considered in the appropriate patients when cardiac symptoms become severe. Balloon valvulotomy in patients with severe pulmonary artery stenosis often results in palliation of symptoms; however, surgery still is required often in these patients.

Octreotide acetate long-acting formulation versus open-label subcutaneous octreotide acetate in malignant carcinoid syndrome

PURPOSE

Subcutaneous (SC) octreotide acetate effectively relieves the diarrhea and flushing associated with carcinoid syndrome but requires long-term multiple injections daily. A microencapsulated long-acting formulation (LAR) of octreotide acetate has been developed for once-monthly intramuscular dosing.

PATIENTS AND METHODS

A randomized trial compared double-blinded octreotide LAR at 10, 20, and 30 mg every 4 weeks with open-label SC octreotide every 8 hours for the treatment of carcinoid syndrome. Seventy-nine patients controlled with treatment of SC octreotide 0.3 to 0.9 mg/d whose symptoms returned during a washout period and who returned for at least the week 20 evaluation constituted the efficacy-assessable population.

RESULTS

Complete or partial treatment success was comparable in each of the four arms of the study (SC, 58.3%; 10 mg, 66.7%; 20 mg, 71.4%; 30 mg, 61.9%; P> or =.72 for all pairwise comparisons). Control of stool frequency was similar in all treatment groups. Flushing episodes were best controlled in the 20-mg LAR and SC groups; the 10-mg LAR treatment was least effective in the control of flushing. Treatment was well tolerated by patients in all four groups.

CONCLUSION

Once octreotide steady-state concentrations are achieved, octreotide LAR controls the symptoms of carcinoid syndrome at least as well as SC octreotide. A starting dose of 20 mg of octreotide LAR is recommended. Supplemental SC octreotide is needed for approximately 2 weeks after initiation of octreotide LAR treatment. Occasional rescue SC injections may be required for possibly 2 to 3 months until steady-state octreotide levels from the LAR formulation are achieved.

Lipiodol avidity of neuroendocrine liver metastases

AIMS

Lipiodol has been shown to concentrate in most hepatocellular carcinomas as well as in some liver metastases, including those of neuroendocrine origin. Our aim was to determine the proportion of neuroendocrine liver metastases that take up lipiodol and to identify tumour characteristics that predict avidity.

METHODS

Avidity was assessed in 12 patients with neuroendocrine liver metastases by performing an abdominal CT scan immediately after selective hepatic arterial injection of 5 ml of unlabelled lipiodol and this was correlated with number and size of lesions as well as angiographic and plain CT scan features.

RESULTS

In seven patients the tumours displayed lipiodol avidity (four solitary, three multiple); five patients had non-avid lesions (all multiple). A large dominant liver tumour was the only predictor of avidity (mean diameter of largest lesion 9 cm vs. 3 cm for patients with non-avid tumours: P=0.01). Avidity was not related to vascularity or CT density of lesions.

CONCLUSIONS

Although this is a small study, it would appear that approximately 50% of neuroendocrine liver metastases selectively concentrate lipiodol, which could have implications for targeted cancer therapy.