Perianaesthetic risks and outcomes of abdominal surgery for metastatic carcinoid tumours

Current Management of Neuroendocrine Tumour Liver Metastases

PURPOSE OF REVIEW

This article aims to illustrate the current state of investigations and management of liver metastases in patients with Neuroendocrine Neoplasms. Neuroendocrine tumours (NETs) are rising in incidence globally and have become the second most prevalent gastrointestinal malignancy in UK and USA. Frequently, patients have metastatic disease at time of presentation. The liver is the most common site of metastases for gastro-enteropancreatic NETs. Characterisation of liver metastases with imaging is important to ensure disease is not under-staged.

RECENT FINDINGS

Magnetic resonance imaging and positron emission tomography are now becoming standard of care for imaging liver metastases. There is an increasing armamentarium of therapies available for management of NETs and loco-regional therapy for liver metastases. The data supporting surgical and loco-regional therapy is reviewed with focus on role of liver transplantation. It is important to use appropriate imaging and classification of NET liver metastases. It is key that decisions regarding approach to treatment is undertaken in a multidisciplinary team and that individualised approaches are considered for management of patients with metastatic NETs.

Comparison of Octreotide and Vasopressors as First-Line Treatment for Intraoperative Carcinoid Crisis

BACKGROUND

Intraoperative carcinoid crisis is typically sudden onset of profound hypotension during operations on patients with neuroendocrine tumors. The crisis was thought to be due to massive release of hormones, and perioperative octreotide was recommended as a prophylaxis against the crisis and as first-line treatment. Recent studies show that octreotide does not prevent the crisis and that no massive release of hormones occurs. Therefore, the authors hypothesized that octreotide is not effective for treating the crisis.

METHODS

A prospective carcinoid anesthesia database was analyzed for occurrences of crisis. Outcomes were compared between protocols when first-line therapy was bolus octreotide and when it was vasopressors without octreotide. Significance was determined by Student's t test, the Mann-Whitney U test, and Fisher's exact test.

RESULTS

Among operations performed with octreotide as first-line treatment (n = 150), crisis occurred for 45 (30 %) patients, the median crisis duration was 6 min, 12 (27 %) patients had crises longer than 10 min, 42 patients (93 %) required subsequent vasopressor administration to resolve the crisis, and 3 (2 %) operations were aborted. Among operations performed with vasopressors as the first-line treatment (n = 195), crisis occurred for 49 (25 %) patients (p = 0.31), the median crisis duration was 3 min (p < 0.001), and no crisis lasted longer than 10 min (p = 0.001). Patients treated with vasopressors were less likely to have multiple crises and had a shorter total time in crisis, a shorter anesthesia time, and no aborted operations (p < 0.05 for all).

CONCLUSIONS

First-line octreotide was ineffective treatment for carcinoid crisis, with patients requiring vasopressors to resolve the crisis, and many crises lasting longer than 10 min. First-line vasopressor treatment resulted in significantly shorter crisis durations, fewer crises and aborted operations, and shorter anesthesia times. Vasopressors should be used as first-line treatment for intraoperative crisis, and treatment guidelines should be changed.

Surgical aspects of small intestinal neuroendocrine tumors

Small intestinal neuroendocrine tumors (NETs) are a heterogeneous group of epithelial tumors with a predominant neuroendocrine differentiation. Although NETs are usually considered rare neoplasms, small intestinal NETs are the most common primary malignancy of the small bowel, with an increasing prevalence worldwide during the course of the past few decades. The indolent nature of these tumors often leads to a delayed diagnosis, resulting in over one-third of patients presenting with synchronous metastases. Primary tumor resection remains the only curative option for this type of tumor. In this review article, the various surgical aspects for the excision of small intestinal NETs are discussed.

Perioperative Carcinoid Crisis: A Systematic Review and Meta-Analysis

Simple Summary

Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication for patients with neuroendocrine tumors (NET). Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting the use of perioperative octreotide to prevent CC. The aim of our meta-analysis was to evaluate the existing evidence characterizing CC and the efficacy of prophylactic octreotide. We found that CC occurs frequently in patients having midgut NETs surgery, specifically those with NET liver metastasis, and is associated with worse postoperative outcomes. Our findings did not show a decreased risk in CC with prophylactic octreotide and questioned the advantage of routine prophylactic octreotide.

Abstract

Background: Surgery is the only curative option for patients with neuroendocrine tumors (NET) and is also indicated for debulking of liver metastasis. Intraoperative carcinoid crisis (CC) is thought to be a potentially lethal complication. Though perioperative octreotide is often recommended for prevention, recent NET society guidelines raised concerns regarding limited data supporting its use. We sought to evaluate existing evidence characterizing CC and evaluating the efficacy of prophylactic octreotide. Methods: A systematic review was performed on studies including patients having surgery for well-differentiated NET and/or NET liver metastasis (2000–2021), and reporting data on the incidence, risk factors, or prognosis of CC, and/or use of prophylactic octreotide. Meta-analysis was performed using random-effects models. Results: Eight studies met inclusion criteria (n = 943 operations). The pooled incidence of CC was 19% (95% CI [0.06–0.36]). Liver metastasis (odds ratio 2.85 [1.49–5.47]) and gender (male 0.58 [0.34–0.99]) were the only significant risk factors. The occurrence of CC was associated with increased risk of major postoperative complications (2.12 [1.03–4.35]). The use of prophylactic octreotide was not associated with decreased risk of CC (0.73 [0.32–1.66]). Notably, there was no standard prophylactic octreotide strategy used. Conclusions: Intraoperative carcinoid crisis is a common complication occurring in up to 20% of patients with midgut NET and/or liver metastasis undergoing surgery. Prophylactic octreotide may not provide an efficient way to prevent this complication. Future studies should focus on prospective evaluation of well-defined prophylactic protocols using a standardized definition for CC.

Shifting Paradigms in the Pathophysiology and Treatment of Carcinoid Crisis

Carcinoid crisis is a potentially fatal condition characterized by various symptoms, including hemodynamic instability, flushing, and diarrhea. The incidence of carcinoid crisis is unknown, in part due to inconsistency in definitions across studies. Triggers of carcinoid crisis include general anesthesia and surgical procedures, but drug-induced and spontaneous cases have also been reported. Patients with neuroendocrine tumors (NETs) and carcinoid syndrome are at risk for carcinoid crisis. The pathophysiology of carcinoid crisis has been attributed to secretion of bioactive substances, such as serotonin, histamine, bradykinin, and kallikrein by NETs. The somatostatin analog octreotide has been considered the standard of care for carcinoid crisis due to its inhibitory effect on hormone release and relatively fast resolution of carcinoid crisis symptoms in several case studies. However, octreotide's efficacy in the treatment of carcinoid crisis has been questioned. This is due to a lack of a common definition for carcinoid crisis, the heterogeneity in clinical presentation, the paucity of prospective studies assessing octreotide efficacy in carcinoid crisis, and the lack of understanding of the pathophysiology of carcinoid crisis. These issues challenge the classical physiologic model of carcinoid crisis and its common etiology with carcinoid syndrome and raise questions regarding the utility of somatostatin analogs in its treatment. As surgical procedures and invasive liver-directed therapies remain important treatment modalities in patients with NETs, the pathophysiology of carcinoid crisis, potential benefits of octreotide, and efficacy of alternative treatment modalities must be studied prospectively to develop an effective evidence-based treatment strategy for carcinoid crisis.

Carcinoid Crisis: A Misunderstood and Unrecognized Oncological Emergency

Carcinoid Crisis represents a rare and extremely dangerous manifestation that can occur in patients with Neuroendocrine Tumors (NETs). It is characterized by a sudden onset of hemodynamic instability, sometimes associated with the classical symptoms of carcinoid syndrome, such as bronchospasm and flushing. Carcinoid Crisis seems to be caused by a massive release of vasoactive substances, typically produced by neuroendocrine cells, and can emerge after abdominal procedures, but also spontaneously in rare instances. To date, there are no empirically derived guidelines for the management of this cancer-related medical emergency, and the available evidence essentially comes from single-case reports or dated small retrospective series. A transfer to the Intensive Care Unit may be necessary during the acute setting, when the severe hypotension becomes unresponsive to standard practices, such as volemic filling and the infusion of vasopressor therapy. The only effective strategy is represented by prevention. The administration of octreotide, anxiolytic and antihistaminic agents represents the current treatment approach to avoid hormone release and prevent major complications. However, no standard protocols are available, resulting in great variability in terms of schedules, doses, ways of administration and timing of prophylactic treatments.

Outcomes and periprocedural management of cardiac implantable electronic devices in patients with carcinoid heart disease

BACKGROUND

Carcinoid heart disease (CHD) is a rare complication of hormonally active neuroendocrine tumors that often requires surgical intervention. Data on cardiac implantable electronic device (CIED) implantation in patients with CHD are limited.

OBJECTIVE

The purpose of this study was to evaluate the experience of CIED implantation in patients with CHD.

METHODS

Patients with a diagnosis of CHD and a CIED procedure from January 1, 1995, through June 1, 2020, were identified using a Mayo Clinic proprietary data retrieval tool. Retrospective review was performed to extract relevant data, which included indications for implant, procedural details, complications, and mortality.

RESULTS

A total of 27 patients (55.6% male; mean age at device implant 65.6 ± 8.8 years) with cumulative follow-up of 75 patient-years (median 1.1 years; interquartile range 0.4-4.6 years) were included for analysis. The majority of implanted devices were dual-chamber permanent pacemakers (63%). Among all CHD patients who underwent any cardiac surgery, the incidence of CIED implantation was 12%. The most common indication for implantation was high-grade heart block (66.7%). Device implant complication rates were modest (14.8%). No patient suffered carcinoid crisis during implantation, and there was no periimplant mortality. Median time from implant to death was 2.5 years, with 1-year mortality of 15%.

CONCLUSION

CHD is a morbid condition, and surgical valve intervention carries associated risks, particularly a high requirement for postoperative pacing needs. Our data suggest that CIED implantation can be performed relatively safely. Clinicians must be aware of the relevant carcinoid physiology and take appropriate precautions to mitigate risks.

Management of Small Bowel Neuroendocrine Tumors

Small bowel neuroendocrine tumors (SBNETS) are slow-growing neoplasms with a noted propensity toward metastasis and comparatively favorable prognosis. The presentation of SBNETs is varied, although abdominal pain and obstructive symptoms are the most common presenting symptoms. In patients with metastases, hypersecretion of serotonin and other bioactive amines results in diarrhea, flushing, valvular heart disease, and bronchospasm, termed carcinoid syndrome. The treatment of SBNETs is multimodal and includes surgery, liver-directed therapy, somatostatin analogues, targeted therapy, and peptide receptor radionuclide therapy.

A prospective study of carcinoid crisis with no perioperative octreotide

BACKGROUND

Carcinoid crises, defined as the sudden onset of hemodynamic instability in patients with neuroendocrine tumors undergoing operation, are associated with significantly increased risk of postoperative complications. Octreotide has been used prophylactically to reduce crisis rates as well as therapeutically to treat crises that still occur. However, studies using octreotide still report crisis rates of 3.4% to 35%, leading to the questioning of its efficacy.

METHODS

Patients with neuroendocrine tumors undergoing operation between 2017 to 2020 with no perioperative octreotide were prospectively studied. Clinicopathologic data were compared by χ² test for discrete variables and by Mann-Whitney U test for continuous variables.

RESULTS

One hundred and seventy-one patients underwent 195 operations. Crisis was documented in 49 operations (25%), with a mean duration of 3 minutes. Crisis was more likely to occur in patients with small bowel primary tumors (P = .012), older age (P = .015), and carcinoid syndrome (P < .001). Those with crises were more likely to have major postoperative complications (P = .003).

CONCLUSION

Completely eliminating perioperative octreotide resulted in neither increased rate nor duration compared with previous studies using octreotide. We conclude perioperative octreotide use may be safely stopped, owing to inefficacy, though the need for an effective medication is clear given continued higher rates of complications.

Percutaneous Image-Guided Core Needle Biopsy of Neuroendocrine Tumors: How Common Is Intraprocedural Carcinoid Crisis?

PURPOSE

To retrospectively evaluate the incidence of carcinoid crisis, other complications, and physiologic disturbances during percutaneous image-guided core needle biopsy of neuroendocrine tumors (NETs) in the lung and the liver.

MATERIALS AND METHODS

Between January 2010 and January 2020, 106 computed tomography (CT) or ultrasound (US)-guided core needle biopsies of lung and liver NETs were performed in 95 consecutive adult patients. The mean age was 64 ± 13 years, and 48% were female. The small bowel was the most common primary site (33%, 31/95), and 32 (34%) patients had pre-existing symptoms of carcinoid syndrome. The mean tumor size was 3.2 ± 2.6 cm, and mean number of passes was 3.4 ± 1.6. A 17/18-gauge needle was used in 91% (96/106) of the biopsies. Thirteen (12%) patients received either outpatient or prophylactic octreotide.

RESULTS

No patients experienced carcinoid crisis or needed octreotide, inotropes, vasopressors, or resuscitation. A single biopsy procedure (0.9%, 1/106) was complicated by bleeding that required angiographic hepatic artery embolization. Changes in pre-biopsy- versus post-biopsy systolic blood pressure and heart rate were -1.6 mm Hg (P = .390) and 0.6 beat/min (P = .431), respectively. Tumor functional status, overall tumor burden, and the elevation of neuroendocrine markers were not associated with intraprocedural physiologic disturbances. There were 4 minor complications (0.4%, 4/106) associated with the biopsy procedure that were not attributed to hormone excretion from tumor manipulation.

CONCLUSIONS

Percutaneous image-guided core biopsy of NETs is safe, with low complication rate and no definite carcinoid crisis in the current cohort.

Surgical Management of Neuroendocrine Tumor Liver Metastases

Patients with neuroendocrine tumor liver metastases (NETLMs) may develop carcinoid syndrome, carcinoid heart disease, or other symptoms from overproduction of hormones. Hepatic resection and cytoreduction is the most direct treatment of NETLMs in eligible patients, and cytoreduction improves symptoms, may reduce the sequelae of carcinoid syndrome, and extends survival. Parenchymal-sparing procedures, such as ablation and enucleation, should be considered during cytoreduction to maximize treatment of multifocal tumors while preserving healthy liver tissue. For patients with large hepatic tumor burdens, high-grade disease, or comorbidities precluding surgery, liver-directed and systemic therapies can be used to palliate symptoms and improve progression-free survival.

Carcinoid Heart Disease: Prognostic Value of 5-Hydroxyindoleacetic Acid Levels and Impact on Survival: A Systematic Literature Review

BACKGROUND

Carcinoid heart disease (CHD) can develop in patients with carcinoid syndrome (CS), itself caused by overproduction of hormones and other products from some neuroendocrine tumours. The most common hormone is serotonin, detected as high 5-hydroxyindoleacetic acid (5-HIAA). This systematic literature review summarises current literature on the impact of CHD on survival, and the relationship between 5-HIAA levels and CHD development, progression, and mortality.

METHODS

MEDLINE, Embase, Cochrane databases, and grey literature were searched using terms for CHD, 5-HIAA, disease progression, and mortality/survival. Eligible articles were non-interventional and included patients with CS and predefined CHD and 5-HIAA outcomes.

RESULTS

Publications reporting on 31 studies were included. The number and disease states of patients varied between studies. Estimates of CHD prevalence and incidence among patients with a diagnosis/symptoms indicative of CS were 3-65% and 3-42%, respectively. Most studies evaluating survival found significantly higher mortality rates among patients with versus without CHD. Patients with CHD reportedly had higher 5-HIAA levels; median urinary levels in patients with versus without CHD were 266-1,381 versus 67.5-575 µmol/24 h. Higher 5-HIAA levels were also found to correlate with disease progression (median progression/worsening-associated levels: 791-2,247 µmol/24 h) and increased odds of death (7% with every 100 nmol/L increase).

CONCLUSIONS

Despite the heterogeneity of studies, the data indicate that CHD reduces survival, and higher 5-HIAA levels are associated with CHD development, disease progression, and increased risk of mortality; 5-HIAA levels should be carefully managed in these patients.

Catheter Ablation in Patients With Neuroendocrine (Carcinoid) Tumors and Carcinoid Heart Disease: Outcomes, Peri-Procedural Complications, and Management Strategies

OBJECTIVES

This report describes a series of patients with neuroendocrine tumors with or without carcinoid heart disease undergoing catheter ablation at the authors' institution.

BACKGROUND

Neuroendocrine (carcinoid) tumors are a rare form of neoplasm with the potential for systemic vasoactive effects and cardiac valvular involvement. These tumors can create peri-operative management challenges for the electrophysiologist. However, there are few data regarding ablation outcomes, periprocedural complications, and management of these patients.

METHODS

All patients with neuroendocrine tumors undergoing catheter ablation at the Mayo Clinic, Rochester, Minnesota over a 25-year period were retrospectively reviewed. From this cohort, the type of arrhythmias ablated, the recurrence of arrhythmia, perioperative complications, and mortality were reviewed and analyzed.

RESULTS

A total of 17 patients (52.9% male; mean age 62.4 ± 9.3 years) with neuroendocrine tumors underwent catheter ablation during the study period. Primary tumor sites included the gastrointestinal tract (n = 11), lung (n = 4), ovary (n = 1), and lymph node (n = 1). Nine patients had metastatic disease, 5 of whom were on somatostatin analog therapy at the time of ablation. Three patients had active symptoms of carcinoid syndrome at the time of ablation, and 2 of those patients had carcinoid heart disease. Ablations were performed mainly for atrial arrhythmias (76.5%): atrioventricular nodal re-entry tachycardia (n = 7), atrial fibrillation (n = 4), and atrial flutter (n = 2). Four patients underwent ablation of ventricular arrhythmias. During a mean follow-up of 19.2 ± 26.2 months, arrhythmia recurred in 35.3% of patients. Three patients (17.6%) had periprocedural complications: pericardial effusion (n = 1), groin site hematoma (n = 1), and carcinoid crisis (n = 1). No deaths were noted in the peri-operative period.

CONCLUSIONS

In a unique cohort of patients with neuroendocrine tumors, catheter ablation was feasible in patients with or without carcinoid syndrome. Carcinoid crisis may occur during the periprocedural period, which can be life-threatening, and a specified protocol for management is important to mitigate this risk.

Octreotide for resuscitation of cardiac arrest due to carcinoid crisis precipitated by novel peptide receptor radionuclide therapy (PRRT): A case report

Peptide receptor radionuclide therapy (PRRT) is an effective treatment for metastatic carcinoid tumours but can precipitate a carcinoid crisis through release of stored bioamines. Cardiac arrest is an uncommon manifestation of carcinoid crisis and has never been reported as a complication of PRRT. We report a case of a 58-year old female who suffered from cardiac arrest following PRRT for metastatic carcinoid tumour. She was successfully resuscitated using intravenous octreotide following 22 min of failure to resuscitate with a standard advanced cardiac life support protocol. Following resuscitation, severe carcinoid heart disease was diagnosed, and the patient subsequently underwent successful surgical valve replacement. Although there is no trial evidence, considering pharmacological rationale and successful outcome in this case, we suggest early administration of intravenous octreotide during resuscitation of patients suffering cardiac arrest post PRRT for carcinoid disease and recommend preventive strategies.

Gastrointestinal neuroendocrine tumors in 2020

Gastrointestinal neuroendocrine tumors are rare slow-growing tumors with distinct histological, biological, and clinical characteristics that have increased in incidence and prevalence within the last few decades. They contain chromogranin A, synaptophysin and neuron-specific enolase which are necessary for making a diagnosis of neuroendocrine tumor. Ki-67 index and mitotic index correlate with cellular proliferation. Serum chromogranin A is the most commonly used biomarker to assess the bulk of disease and monitor treatment and is raised in both functioning and non-functioning neuroendocrine tumors. Most of the gastrointestinal neuroendocrine tumors are non-functional. World Health Organization updated the classification of neuroendocrine tumors in 2017 and renamed mixed adenoneuroendocrine carcinoma into mixed neuroendocrine neoplasm. Gastric neuroendocrine tumors arise from enterochromaffin like cells. They are classified into 4 types. Only type I and type II are gastrin dependent. Small intestinal neuroendocrine tumor is the most common small bowel malignancy. More than two-third of them occur in the terminal ileum within 60 cm of ileocecal valve. Patients with small intestinal neuroendrocrine tumors frequently show clinical symptoms and develop distant metastases more often than those with neuroendocrine tumors of other organs. Duodenal and jejuno-ileal neuroendocrine tumors are distinct biologically and clinically. Carcinoid syndrome generally occurs when jejuno-ileal neuroendocrine tumors metastasize to the liver. Appendiceal neuroendocrine tumors are generally detected after appendectomy. Colonic neuroendocrine tumors generally present as a large tumor with local or distant metastasis at the time of diagnosis. Rectal neuroendocrine tumors are increasingly being diagnosed since the implementation of screening colonoscopy in 2000. Gastrointestinal neuroendocrine tumors are diagnosed and staged by endoscopy with biopsy, endoscopic ultrasound, serology of biomarkers, imaging studies and functional somatostatin scans. Various treatment options are available for curative and palliative treatment of gastrointestinal neuroendocrine tumors.

Surgery and Perioperative Management in Small Intestinal Neuroendocrine Tumors

Small-intestinal neuroendocrine tumors (SI-NETs) are the most prevalent small bowel neoplasms with an increasing frequency. In the multimodal management of SI-NETs, surgery plays a key role, either in curative intent, even if R0 resection is feasible in only 20% of patients due to advanced stage at diagnosis, or palliative intent. Surgeons must be informed about the specific surgical management of SI-NETs according to their hormonal secretion, their usual dissemination at the time of diagnosis and the need for bowel-preserving surgery to avoid short bowel syndrome. The aim of this paper is to review the surgical indications and techniques, and perioperative and postoperative management of SI-NETs.

Update on Pathophysiology, Treatment, and Complications of Carcinoid Syndrome

Carcinoid syndrome (CS) develops in patients with hormone-producing neuroendocrine neoplasms (NENs) when hormones reach a significant level in the systemic circulation. The classical symptoms of carcinoid syndrome are flushing, diarrhoea, abdominal pain, and wheezing. Neuroendocrine neoplasms can produce multiple hormones: 5-hydroxytryptamine (serotonin) is the most well-known one, but histamine, catecholamines, and brady/tachykinins are also released. Serotonin overproduction can lead to symptoms and also stimulates fibrosis formation which can result in development of carcinoid syndrome-associated complications such as carcinoid heart disease (CaHD) and mesenteric fibrosis. Transforming growth factor beta (TGF-β) is one of the main factors in developing fibrosis, but platelet-derived growth factor (PDGF), basic fibroblast growth factor (FGF2), and connective tissue growth factor (CTGF or CCN2) are also related to fibrosis development. Treatment of CS focuses on reducing serotonin levels with somatostatin analogues (SSA's). Telotristat ethyl and peptide receptor radionuclide therapy (PRRT) have recently become available for patients with symptoms despite being established on SSA's. Screening for CaHD is advised, and early intervention prolongs survival. Mesenteric fibrosis is often present and associated with poorer survival, but the role for prophylactic surgery of this is unclear. Depression, anxiety, and cognitive impairment are frequently present symptoms in patients with CS but not always part of their care plan. The role of antidepressants, mainly SSRIs, is debatable, but recent retrospective studies show evidence for safe use in patients with CS. Carcinoid crisis is a life-threatening complication of CS which can appear spontaneously but mostly described during surgery, anaesthesia, chemotherapy, PRRT, and radiological procedures and may be prevented by octreotide administration.

The North American Neuroendocrine Tumor Society Consensus Paper on the Surgical Management of Pancreatic Neuroendocrine Tumors

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the surgical management of pancreatic neuroendocrine tumors from July 19 to 20, 2018. The group reviewed a series of questions of specific interest to surgeons taking care of patients with pancreatic neuroendocrine tumors, and for each, the available literature was reviewed. What follows are these reviews for each question followed by recommendations of the panel.

Periprocedural Management of Patients Undergoing Liver Resection or Embolotherapy for Neuroendocrine Tumor Metastases

OBJECTIVES

The objective of this study was to describe the periprocedural management of patients with well-differentiated neuroendocrine tumors with hepatic metastases who underwent liver-directed procedures.

METHODS

We performed a retrospective review of patients with metastatic neuroendocrine tumors who underwent liver resection, ablation, or embolotherapy at a single center from 2012 to 2016. The primary outcome was occurrence of documented carcinoid crisis (CC) or hemodynamic instability (HDI), defined as 10 minutes or more of systolic blood pressure less than 80 or greater than 180 mm Hg, or pulse greater than 120 beats per minute.

RESULTS

We identified 75 patients who underwent liver resection/ablation (n = 38) or embolotherapy (n = 37). Twenty-four patients (32%) experienced CC or HDI (CC/HDI); CC occurred in 3 patients. No clinicopathologic or procedural factors, including procedure type, octreotide or long-acting somatostatin analog use, and history of carcinoid syndrome, were associated with CC/HDI. Grades 2 to 4 complications were reported in 42% of patients who experienced CC/HDI versus in 16% of patients who did not experience CC/HDI (P < 0.05).

CONCLUSIONS

A significant portion of patients developed CC/HDI, and these patients were more likely to develop severe postprocedural complications. Periprocedural octreotide use was not associated with lower CC/HDI occurrence, but continued use is advised given its safety profile until additional studies definitively demonstrate lack of benefit.

Β-Adrenergic agonist administration is not associated with secondary carcinoid crisis in patients with carcinoid tumor

BACKGROUND

Patients with carcinoid tumors are at risk for profound intraoperative hypotension known as carcinoid crisis, which catecholamines are traditionally believed to trigger. However, data supporting this are lacking.

METHODS

Anesthesia records were retrospectively reviewed for carcinoid patients treated with vasopressors. Hemodynamics for those with crisis were compared between those who received β-adrenergic agonists (B-AA) versus those who did not.

RESULTS

Among 293 consecutive operations, 58 were marked by 161 crises. There was no significant difference in the incidence of paradoxical hypotension with B-AA compared to non-B-AA (p = 0.242). The maximum percent decrease in mean arterial pressure following drug administration was significantly greater in those patients treated with non-B-AA than with B-AA (31.6% vs. 12.5%, p < 0.0001). There were no differences in crisis duration (p = 0.257) or postoperative complication rate (p = 0.896).

CONCLUSIONS

β-Adrenergic agonist use was not associated with paradoxical hypotension, prolonged carcinoid crisis, or postoperative complications in patients with intraoperative carcinoid crisis.

Intraoperative carcinoid syndrome during small-bowel neuroendocrine tumour surgery

Only few descriptions of intraoperative carcinoid syndrome (ioCS) have been reported. The primary objective of this study was to describe ioCS. A second aim was to identify risk factors of ioCS. We retrospectively analysed patients operated for small-bowel neuroendocrine tumour in our institution between 2007 and 2015, and receiving our preventive local regimen of octreotide continuous administration. ioCS was defined as highly probable in case of rapid (<5 min) arterial blood pressure changes ≥40%, not explained by surgical/anaesthetic management and regressive ≥20% after octreotide bolus injection. Probable cases were ioCS which did not meet all criteria of highly-probable ioCS. Suspected ioCS were detected on the anaesthesia record by an injection of octreotide due to a manifestation which did not meet the criteria for highly-probable or probable ioCS. A total of 81 patients (liver metastases: 59, prior carcinoid syndrome: 49, carcinoid heart disease: 7) were included; 139 ioCS occurred in 45 patients: 45 highly probable, 67 probable and 27 suspected. ioCs was hypertensive (91%) and/or hypotensive (29%). There was no factor, including the use of vasopressors, significantly associated with the occurrence of an ioCS. All surgeries were completed and one patient died from cardiac failure 4 days after surgery. After preoperative octreotide continuous infusion, ioCS were mainly hypertensive. No ioCS risk factors, including vasopressor use, were identified. No intraoperative carcinoid crisis occurred, suggesting the clinical relevance of a standardized octreotide prophylaxis protocol.

A prospective study of the pathophysiology of carcinoid crisis

BACKGROUND

Sudden massive release of serotonin, histamine, kallikrein, and bradykinin is postulated to cause an intraoperative carcinoid crisis. The exact roles of each of these possible agents, however, remain unknown. Optimal treatment will require an improved understanding of the pathophysiology of the carcinoid crisis.

METHODS

Carcinoid patients with liver metastases undergoing elective abdominal operations were studied prospectively, using intraoperative, transesophageal echocardiography, pulmonary artery catheterization, and intraoperative blood collection. Serotonin, histamine, kallikrein, and bradykinin levels were analyzed by enzyme-linked immunosorbent assay.

RESULTS

Of 46 patients studied, 16 had intraoperative hypotensive crises. Preincision serotonin levels were greater in patients who had crises (1,064 vs 453 ng/mL, P = .0064). Preincision hormone profiles were otherwise diverse. Cardiac function on transesophageal echocardiography during the crisis was normal, but intracardiac hypovolemia was observed consistently. Pulmonary artery pressure decreased during crises (P = .025). Linear regression of preincision serotonin levels showed a positive relationship with mid-crisis cardiac index (r = 0.73, P = .017) and a negative relationship with systemic vascular resistance (r=-0.61, P = .015). There were no statistically significant increases of serotonin, histamine, kallikrein, or bradykinin levels during the crises.

CONCLUSION

The pathophysiology of carcinoid crisis appears consistent with distributive shock. Hormonal secretion from carcinoid tumors varies widely, but increased preincision serotonin levels correlate with crises and with hemodynamic parameters during the crises. Statistically significant increases of serotonin, histamine, kallikrein, or bradykinin during the crises were not observed.

Influence of carcinoid syndrome on the clinical characteristics and outcomes of patients with gastroenteropancreatic neuroendocrine tumors undergoing operative resection

BACKGROUND

The incidence, clinical characteristics, and long-term outcomes of patients with gastroenteropancreatic neuroendrocrine tumors and carcinoid syndrome undergoing operative resection have not been well characterized.

METHODS

Patients undergoing resection of primary or metastatic gastroenteropancreatic neuroendrocrine tumors between 2000 and 2016 were identified from an 8-institution collaborative database. Clinicopathologic and postoperative characteristics as well as overall survival and disease-free survival were compared among patients with and without carcinoid syndrome.

RESULTS

Among 2,182 patients who underwent resection, 139 (6.4%) had preoperative carcinoid syndrome. Patients with carcinoid syndrome were more likely to have midgut primary tumors (44.6% vs 21.4%, P < .001), lymph node metastasis (63.4% vs 44.3%, P < .001), and metastatic disease (62.8% vs 26.7%, P < .001). There was no difference in tumor differentiation, grade, or Ki67 status. Perioperative carcinoid crisis was rare (1.6% vs 0%, P < .01), and the presence of preoperative carcinoid syndrome was not associated with postoperative morbidity (38.8% vs 45.5%, P = .129). Substantial symptom improvement was reported in 59.5% of patients who underwent curative-intent resection, but occurred in only 22.7% who underwent debulking. Despite an association on univariate analysis (P = .04), carcinoid syndrome was not independently associated with disease-free survival after controlling for confounding factors (hazard ratio 0.97, 95% confidence interval 0.64-1.45). Preoperative carcinoid syndrome was not associated with overall survival on univariate or multivariate analysis.

CONCLUSION

Among patients undergoing operative resection of gastroenteropancreatic neuroendrocrine tumors, the prevalence of preoperative carcinoid syndrome was low. Although operative intervention with resection or especially debulking in patients with carcinoid syndrome was disappointing and often failed to improve symptoms, after controlling for markers of tumor burden, carcinoid syndrome was not independently associated with worse disease-free survival or overall survival.

Small Bowel and Colorectal Carcinoids

Neuroendocrine tumors, or carcinoid tumors, of both the midgut and hindgut are quite rare, but their incidence is increasing. Surgery is the treatment of choice in patients who can tolerate an operation and have operable disease. Options for the treatment of metastatic disease include cytoreductive surgery, somatostatin analogues, interferon α, local liver therapies (hepatic arterial embolization, ablation), chemotherapy, Peptide-Receptor Radionucleotide Radiotherapy, angiogenesis inhibitors, and mammalian target of rapamycin inhibitors.

New Treatments for the Carcinoid Syndrome

Neuroendocrine tumors, including carcinoids, are rare and insidiously growing tumors. Related to their site of origin, tumors can be functional, causing various forms of the carcinoid syndrome, owing to the overproduction of serotonin, histamine, or other bioactive substances. They often invade adjacent structures or metastasize to the liver and elsewhere. Treatment includes multimodal approaches, including cytoreductive surgery, locoregional embolization, cytotoxic therapy, peptide receptor radionuclide therapy, and various targeted therapies with goals of symptom relief and control of tumor growth. This article summarizes current and emerging approaches to management and reviews several promising future therapies.

Partial hepatic resections for metastatic neuroendocrine tumors: perioperative outcomes

STUDY OBJECTIVE

Partial hepatic resection reduces tumor burden in patients with metastatic neuroendocrine tumors, thereby improving quality and length of life. These procedures can be challenging as well as life-threatening. Our aim was to evaluate our patients' perioperative outcomes and propose a definition for an intraoperative carcinoid crisis relevant to this surgery, given its unique surgical considerations.

DESIGN

Retrospective study.

SETTING

Mayo Clinic, Rochester, Minnesota.

PATIENTS

One hundred sixty-nine patients undergoing partial hepatic resection for metastatic neuroendocrine tumors between 1997 and 2015 were identified retrospectively from a surgical database at Mayo Clinic Rochester.

INTERVENTIONS

None.

MEASUREMENTS

Intraoperative carcinoid crisis for patients undergoing hepatic resection of neuroendocrine tumors was defined. Patients' medical records were reviewed and data were abstracted describing patient and procedural characteristics and perioperative outcomes.

MAIN RESULTS

There were no documented cases of carcinoid crisis (0.0%, 95% C.I. 0.0% to 2.2%). One patient developed clinical findings of an emerging carcinoid crisis, but was successfully treated with doses of octreotide and findings resolved in <10 min. Prophylactically 500 μg octreotide was given subcutaneously in 77% (130/169) of patients preoperatively.

CONCLUSIONS

There were no documented cases of carcinoid crisis (0.0%, 95% C.I. 0.0% to 2.2%). Adverse events were infrequent.

Prevention and management of carcinoid crises in patients with high-risk neuroendocrine tumours undergoing peptide receptor radionuclide therapy (PRRT): Literature review and case series from two Australian tertiary medical institutions

Peptide receptor radionuclide therapy (PRRT) is an important therapeutic option for somatostatin receptor (SSTR) positive metastatic and/or inoperable neuroendocrine tumours (NETs). However, in patients with poorly controlled carcinoid syndrome, it may lead to an acute flare of carcinoid symptoms or even carcinoid crisis. We report seven patients who received PRRT with (¹⁷⁷Lu-DOTA⁰, Tyr³) octreotate (¹⁷⁷Lu-octreotate-LuTate) across two Australian tertiary medical institutions who developed acute flare of carcinoid symptoms/carcinoid crisis during/after PRRT. Cases were identified as high-risk due to previous history of carcinoid crises, high tumour burden and markedly elevated tumour markers. We propose a protocol to prevent and manage severe carcinoid symptoms in high-risk patients treated with PRRT.

Fatal Systemic Vasoconstriction in a Case of Metastatic Small-Intestinal NET

An increased release of serotonin secreted by ileal NETs is thought to be the major factor causing the carcinoid syndrome. However, in acutely arising carcinoid crisis also other vasoactive factors may lead to hazardous fluctuations in blood pressure and bronchial constriction. In rare cases, systemic vasoconstriction can be observed, probably caused by catecholamines or similar acting substances. Here, we report a fatal case of fulminant systemic vasoconstriction possibly caused by catecholamines in a patient with metastasized ileal NET. The vasospasm was detected by CT-angiography, and hemodynamic monitoring revealed a high systemic vascular resistance. Epinephrine, norepinephrine, and chromogranin A levels in plasma were elevated as was the urinary 5-hydroxyindoleacetic acid (5-HIAA). The cause of death was heart failure due to severe circulatory insufficiency. The progression of the tumor disease was confirmed by autopsy.

The Surgical Management of Small Bowel Neuroendocrine Tumors: Consensus Guidelines of the North American Neuroendocrine Tumor Society

Small bowel neuroendocrine tumors (SBNETs) have been increasing in frequency over the past decades, and are now the most common type of small bowel tumor. Consequently, general surgeons and surgical oncologists are seeing more patients with SBNETs in their practices than ever before. The management of these patients is often complex, owing to their secretion of hormones, frequent presentation with advanced disease, and difficulties with making the diagnosis of SBNETs. Despite these issues, even patients with advanced disease can have long-term survival. There are a number of scenarios which commonly arise in SBNET patients where it is difficult to determine the optimal management from the published data. To address these challenges for clinicians, a consensus conference was held assembling experts in the field to review and discuss the available literature and patterns of practice pertaining to specific management issues. This paper summarizes the important elements from these studies and the recommendations of the group for these questions regarding the management of SBNET patients.

ENETS Consensus Guidelines for the Standards of Care in Neuroendocrine Tumors: Pre- and Perioperative Therapy in Patients with Neuroendocrine Tumors

Neuroendocrine tumors of the small intestine are the most common causes of the carcinoid syndrome. Carcinoid heart disease occurs in more than half of the patients with the carcinoid syndrome. Patients with carcinoid heart disease who need to undergo surgery should also undergo preoperative evaluation by an expert cardiologist. Treatment with long-acting somatostatin analogs aims at controlling the excessive hormonal output and symptoms related to the carcinoid syndrome and at preventing a carcinoid crisis during interventions. Patients with a gastrinoma require pre- and postoperative treatment with high doses of proton pump inhibitors. Patients with a glucagonoma require somatostatin analog treatment and nutritional supplementation. Patients with a VIPoma also require somatostatin analog treatment and intravenous fluid and electrolyte therapy. Insulinoma patients generally require intravenous glucose infusion prior to operation. In patients with localized operable insulinoma, somatostatin analog infusion should only be considered after the effect of this therapy has been electively studied.

Early and Late Outcomes of Surgical Treatment in Carcinoid Heart Disease

BACKGROUND

Symptoms and survival of patients with carcinoid syndrome have improved, but development of carcinoid heart disease (CaHD) continues to decrease survival.

OBJECTIVES

This study aimed to analyze patient outcomes after valve surgery for CaHD during a 27-year period at 1 institution to determine early and late outcomes and opportunities for improved patient care.

METHODS

We retrospectively studied the short-term and long-term outcomes of all consecutive patients with CaHD who underwent valve replacement at our institution between 1985 and 2012.

RESULTS

The records of 195 patients with CaHD were analyzed. Pre-operative New York Heart Association class was III or IV in 125 of 178 patients (70%). All had tricuspid valve replacement (159 bioprostheses, 36 mechanical), and 157 underwent a pulmonary valve operation. Other concomitant operations included mitral valve procedure (11%), aortic valve procedure (9%), patent foramen ovale or atrial septal defect closure (23%), cardiac metastasectomies or biopsy (4%), and simultaneous coronary artery bypass (11%). There were 20 perioperative deaths (10%); after 2000, perioperative mortality was 6%. Survival rates (95% confidence intervals) at 1, 5, and 10 years were 69% (63% to 76%), 35% (28% to 43%), and 24% (18% to 32%), respectively. Overall mortality was associated with older age, cytotoxic chemotherapy, and tobacco use; 75% of survivors had symptomatic improvement at follow-up. Presymptomatic valve operation was not associated with late survival benefit.

CONCLUSIONS

Operative mortality associated with valve replacement surgery for CaHD has decreased. Symptomatic and survival benefit is noted in most patients when CaHD is managed by an experienced multidisciplinary team.

Continuous infusion of octreotide combined with perioperative octreotide bolus does not prevent intraoperative carcinoid crisis

BACKGROUND

Operations and anesthesia in carcinoid patients can provoke carcinoid crises, which can have serious sequelae, including death. Prophylactic octreotide is recommended to prevent crises. Recommended prophylaxis regimens vary from octreotide long-acting repeatable to preoperative bolus to continuous octreotide infusion; however, efficacy data are lacking. We have shown previously that crises correlated with major complications and that octreotide long-acting repeatable and preoperative bolus failed to prevent crises. This study examines the impact of continuous octreotide infusion.

METHODS

A total of 127 patients (71% with liver metastases, 74% with carcinoid syndrome) who underwent 150 operations with continuous octreotide infusions were enrolled in this prospective case series. Our main outcome measures were the occurrence of intraoperative carcinoid crises and post-operative complications.

RESULTS

Crises occurred at a rate of 30% as compared with 24% in our previous series, which examined the impact of preoperative octreotide bolus. Crises were significantly associated with the presence of hepatic metastases (P = .02) or history of carcinoid syndrome (P = .006), although neither was required for crises. Prompt vasopressor treatment shortened the mean duration of hypotension to 8.7 minutes, compared with 19 minutes in our prior series. Crises no longer correlated with major complications (P = .481) unless instability persisted for greater than 10 minutes (P = .011).

CONCLUSION

Octreotide infusions do not prevent intraoperative crises. Patients without liver metastases or carcinoid syndrome can have intraoperative crises. Postoperative complications can be decreased by reducing the duration of crises. Further study is needed to determine how best to shorten hemodynamic instability during crises.

Somatostatin analogues do not prevent carcinoid crisis

BACKGROUND

Carcinoid crisis is a life-threatening syndrome of neuroendocrine tumors (NETs) characterized by dramatic blood pressure fluctuation, arrhythmias, and bronchospasm. In the era of booming anti-tumor therapeutics, this has become more important since associated stresses can trigger carcinoid crisis. Somatostatin analogues (SSTA) have been recommended for prophylactic administration before intervention procedures for functioning NETs. However, the efficacy is still controversial. The aim of this article is to review efficacy of SSTA for preventing carcinoid crisis.

MATERIALS AND METHODS

PubMed, Cochrane Controlled trials Register, and EMBASE were searched using 'carcinoid crisis' as a search term combining terms with 'somatostatin'; 'octreotide'; 'lanreotide' and 'pasireotide' until December 2013.

RESULTS

Twenty-eight articles were retrieved with a total of fifty-three unique patients identified for carcinoid crisis. The most common primary sites of NETs were the small intestine and respiratory tract. The triggering factors for carcinoid crisis included anesthesia/ surgery (63.5%), interventional therapy (11.5%), radionuclide therapy (9.6%), examination (7.7%), medication (3.8%), biopsy (2%) and spontaneous (2%). No randomized controlled trials (RCTs) were identified and two case-control studies were included to assess the efficacy of SSTA for preventing carcinoid crisis by meta-analysis. The overall pooled risk of perioperative carcinoid crisis was similar despite the prophylactic administration of SSTA (OR 0.44, 95% CI: 0.14 to 1.35, p=0.15).

CONCLUSIONS

SSTA was not helpful for preventing carcinoid crisis based on a meta-analysis of retrospective studies. Attentive monitoring and careful intervention are essential. Future studies with better quality are needed to clarify any effect of SSTA for preventing carcinoid crisis.

Current cancer therapies - a guide for perioperative physicians

Cancer is expected to be the leading cause of death around the world. New cancer therapies have improved survival but they can also lead to complications and toxicity. In this article, the effects of modern anti-cancer therapies are reviewed. The perioperative effects of chemotherapy, radiotherapy and experimental therapies in relation to anaesthesia are discussed. Common and rare complications are summarised as is advice for optimal treatment of the cancer patient in the perioperative period.

Octreotide LAR and bolus octreotide are insufficient for preventing intraoperative complications in carcinoid patients

BACKGROUND AND OBJECTIVES

Surgery in carcinoid patients can provoke a carcinoid crisis, which can have serious sequelae, including death. Octreotide prophylaxis is recommended to prevent carcinoid crisis, however there are few reports of outcomes and no large series examining its efficacy. We hypothesized that a 500 µg prophylactic octreotide dose is sufficient to prevent carcinoid crisis.

METHODS

Records of carcinoid patients undergoing abdominal operations during years 2007-2011 were retrospectively reviewed. Octreotide use and intraoperative and postoperative outcomes were analyzed.

RESULTS

Ninety-seven intraabdominal operations performed by a single surgeon were reviewed. Ninety percent of patients received preoperative prophylactic octreotide. Fifty-six percent received at least one additional intraoperative dose. Twenty-three patients (24%) experienced an intraoperative complication. Intraoperative complications correlated with presence of hepatic metastases but not presence of carcinoid syndrome. Postoperative complications occurred in 60% of patients with intraoperative complications versus 31% of those with none (P = 0.01).

CONCLUSIONS

Significant intraoperative complications occur frequently in patients with hepatic metastases regardless of presence of carcinoid syndrome and despite octreotide LAR or single dose prophylactic octreotide. Occurrence of such events correlates strongly with postoperative complications. Randomized controlled trials are needed to determine whether the administration of prophylactic octreotide is beneficial.

Mega-dose intravenous octreotide for the treatment of carcinoid crisis: a systematic review

PURPOSE

Carcinoid crises are rare life-threatening events involving cardiac instability when carcinoid tumours release vasoactive peptides. Such events can occur in the perioperative setting. Octreotide, a somatostatin analogue, is administered as a bolus dose of 100-500 μg iv or by infusion to treat carcinoid crises. Due to the apparent low risk-to-benefit profile, a much higher dose is sometimes used in urgent situations. The purpose of this study was to assess the evidence for administering doses or hourly infusions of octreotide that exceeded 1,500 μg iv to treat carcinoid crises. We also sought to identify which patients may require large doses and to describe the adverse effects of such doses.

SOURCE

We systematically searched Medline, EMBASE, and Cochrane databases and hand-searched reference lists of relevant articles in 2006 and again in 2010 and 2011. All study designs were included in our search. Resolution of crisis symptoms was the primary outcome.

PRINCIPAL FINDINGS

Eighteen articles were included. No patient died during a carcinoid crisis. A retrospective chart review of 89 patients with carcinoid heart disease reported octreotide doses of 25-54,000 μg to treat carcinoid crises, although neither crisis symptoms nor outcomes were described.

CONCLUSION

In the included case reports, carcinoid crises were managed effectively using octreotide 25-500 μg iv. Previous exposure to octreotide and carcinoid heart disease may warrant the need for higher doses. In addition to the low quality of the articles and the small sample size, inconsistent use of the term "carcinoid crisis" and paucity of reported outcomes were also limitations of this systematic review. These findings highlight the need for further investigation into dose-response relationships of octreotide for the treatment of carcinoid crisis.

[Extent of resection for neuroendocrine tumors of the small intestine]

Neuroendocrine tumors of the small intestine have been diagnosed with increasing frequency over the past 35 years and presently account for approximately 2% of all gastrointestinal neoplasms. While most of these tumors are discovered incidentally during emergency laparotomy or in the clinical setting of unknown primary cancer with hepatic metastases, the growing awareness of this rare entity and improved diagnostic methods promote earlier diagnosis. The classical carcinoid syndrome with flush, diarrhea and cardiac strain is observed only in 20-30% of patients. The clinical symptoms necessitate a special preoperative preparation of the patient including evaluation of cardiac function.Prospective studies assessing the efficacy of surgical treatment strategies for neuroendocrine neoplasms of the small intestine do not exist. However, retrospective studies have demonstrated that curative as well as palliative resection of the primary tumor improves the prognosis and the quality of life of patients. Besides limited resection of the small bowel in order to avoid postoperative short bowel syndrome an effective clearance of the regional lymph nodes is essential. A primary tumor site in the terminal ileum requires dissection of the lymph nodes on the right side of the ileocolic artery which usually implies an additional resection of the right colon. In cases of a primary tumor site located in the lower ileum up to the distal jejunum, a cone-shaped resection of the mesenterium of the small bowel with extension of lymphadenectomy into adjacent segments with preservation of vascularization is performed.

Carcinoid syndrome and perioperative anesthetic considerations

Carcinoid tumors are uncommon, slow-growing neoplasms. These tumors are capable of secreting numerous bioactive substances, which results in significant potential challenges in the management of patients afflicted with carcinoid syndrome. Over the past two decades, both surgical and medical therapeutic options have broadened, resulting in improved outcomes. The pathophysiology, clinical signs and symptoms, diagnosis, treatment options, and perioperative management, including anesthetic considerations, of carcinoid syndrome are presented.

Role of somatostatins in gastroenteropancreatic neuroendocrine tumor development and therapy

The incidence and prevalence of gastroenteropancreatic neuroendocrine tumors (GEP-NETs) have increased in the past 20 years. GEP-NETs are heterogeneous tumors, in terms of clinical and biological features, that originate from the pancreas or the intestinal tract. Some GEP-NETs grow very slowly, some grow rapidly and do not cause symptoms, and others cause hormone hypersecretion and associated symptoms. Most GEP-NETs overexpress receptors for somatostatins. Somatostatins inhibit the release of many hormones and other secretory proteins; their effects are mediated by G protein-coupled receptors that are expressed in a tissue-specific manner. Most GEP-NETs overexpress the somatostatin receptor SSTR2; somatostatin analogues are the best therapeutic option for functional neuroendocrine tumors because they reduce hormone-related symptoms and also have antitumor effects. Long-acting formulations of somatostatin analogues stabilize tumor growth over long periods. The development of radioactive analogues for imaging and peptide receptor radiotherapy has improved the management of GEP-NETs. Peptide receptor radiotherapy has significant antitumor effects, increasing overall survival times of patients with tumors that express a high density of SSTRs, particularly SSTR2 and SSTR5. The multi-receptor somatostatin analogue SOM230 (pasireotide) and chimeric molecules that bind SSTR2 and the dopamine receptor D2 are also being developed to treat patients with GEP-NETs. Combinations of radioactive labeled and unlabeled somatostatin analogues and therapeutics that inhibit other signaling pathways, such as mammalian target of rapamycin (mTOR) and vascular endothelial growth factor, might be the most effective therapeutics for GEP-NETs.

Monitoring endocrine function

This article reviews current knowledge concerning the monitoring of endocrine function in patients in the clinical setting. Monitoring techniques are discussed and literature is reviewed regarding diabetes mellitus, thyroid, and parathyroid disorders, pheochromocytoma, adrenal insufficiency, and carcinoid tumors.

[Anaesthesia for endocrine tumor removal]

Endocrine tumors could be defined by their ability to produce structural proteins or hormones common to nervous and endocrine cells. They might induce physiological transforms or outcome adverse events which should be well known in order to prevent or treat them early. The goal of this review was to describe these changes, to describe preoperative assessment, and to discuss intraoperative monitoring and drugs choice based on the literature from the last 30 years. As an example, it should be noticed that: (1) preoperative blood pressure control is essential to prepare phaeochromocytoma for surgery. It should be followed during anaesthesia by intensive fluid load, reversible anaesthetic drugs and rational cardiovascular medications use (as for example remifentanil, sevoflurane, calcium channel blockers and esmolol), and after surgery by narrow clinical and biological monitoring; (2) after medullar thyroid cancer, main adverse events include cervical compressive haematoma and recurrent laryngeal nerve injury as for any thyroid surgery; (3) during pituitary surgery, air embolism might be expected, whereas water dysregulation (diabetes insipidus), corticotroph insufficiency, cerebrospinal fluid (CSF) leak might occur postoperatively. In acromegaly, difficult endotracheal intubation is possible whereas severe Cushing's syndrome may be complicated with hypertensive cardiac failure, infections, thrombosis, delayed cicatrisation; (4) somatostatine analogs are a keystone in carcinoid tumors preoperative and anaesthetic management.