Carcinoid crisis induced by receptor radionuclide therapy with 90Y-DOTATOC in a case of liver metastases from bronchial neuroendocrine tumor (atypical carcinoid)

Update in the management of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine neoplasms are a diverse group of neoplasms that can occur in various areas throughout the body. Well-differentiated neuroendocrine tumors (NETs) most often arise in the gastrointestinal tract, termed gastroenteropancreatic neuroendocrine tumors (GEP-NETs). Although GEP-NETs are still uncommon, their incidence and prevalence have been steadily increasing over the past decades. The primary treatment for GEP-NETs is surgery, which offers the best chance for a cure. However, because GEP-NETs are often slow-growing and do not cause symptoms until they have spread widely, curative surgery is not always an option. Significant advances have been made in systemic and locoregional treatment options in recent years, including peptide-receptor radionuclide therapy with α and β emitters, somatostatin analogs, chemotherapy, and targeted molecular therapies.

Carcinoid crisis: The challenge is still there

Carcinoid crisis (CC) has classically been considered the extreme end of the spectrum of carcinoid syndrome (CS). However, this presumption and other aspects of CC remain poorly understood. Consequently, current clinical guidelines are based on a low quality of evidence. There is no standard definition of CC and its incidence is unknown. Patients with florid CS and elevated serotonin (or its derivatives) which develop CC have been reported during decades. Nevertheless, the hypothesis that CC is due to the sudden massive release of serotonin or other vasoactive substances is unproven. Many triggers of CC (surgery, anaesthesia, peptide receptor radionuclide therapy, tumour biopsy or liver-directed treatments) have been proposed. However, data from studies are heterogeneous and even contradictory. Finally, the role of octreotide in the prevention of CC has been questioned. Herein, we report a clinical case and perform a critical review of the evidence available today on this topic.

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.

A case of metastatic neuroendocrine disease and cholecystitis: surgical remedy and management of carcinoid crisis

The report presents a case of a 70-year-old male with a known mesenteric neuroendocrine tumour and metastases to the liver diagnosed with acute cholecystitis. During surgery, the patient developed a carcinoid crisis with mixed distributive and cardiogenic shock involving systemic vasodilation and arrhythmia. During surgical procedures, carcinoid crisis can be precipitated by tumours that secrete a pathological shower of vasoactive mediators. Somatostatin analogues are utilized to control carcinoid syndrome and are routinely used peri-operatively. However, no standard infusion regimen exists. The case raises the suggestion that metastatic liver neuroendocrine disease may confound the diagnosis of cholecystitis, complicates the management of acute surgical presentations and highlights the need for agreement on octreotide therapy for surgical patients with carcinoid tumours.

90Y/177Lu-DOTATOC: From Preclinical Studies to Application in Humans

The PRRT (Peptide Receptor Radionuclide Therapy) is a promising modality treatment for patients with inoperable or metastatic neuroendocrine tumors (NETs). Progression-free survival (PFS) and overall survival (OS) of these patients are favorably comparable with standard therapies. The protagonist in this type of therapy is a somatostatin-modified peptide fragment ([Tyr3] octreotide), equipped with a specific chelating system (DOTA) capable of creating a stable bond with β-emitting radionuclides, such as yttrium-90 and lutetium-177. In this review, covering twenty five years of literature, we describe the characteristics and performances of the two most used therapeutic radiopharmaceuticals for the NETs radio-treatment: [90Y]Y-DOTATOC and [177Lu]Lu-DOTATOC taking this opportunity to retrace the most significant results that have determined their success, promoting them from preclinical studies to application in humans.

Peptide-drug conjugate-based novel molecular drug delivery system in cancer

Drug delivery systems are generally believed to comprise drugs and excipients. A peptide-drug conjugate is a single molecule that can simultaneously play multiple roles in a drug delivery system, such as in vivo drug distribution, targeted release, and bioactivity functions. This molecule can be regarded as an integrated drug delivery system, so it is called a molecular drug delivery system. In the context of cancer therapy, a peptide-drug conjugate comprises a tumor-targeting peptide, a payload, and a linker. Tumor-targeting peptides specifically identify membrane receptors on tumor cells, improve drug-targeted therapeutic effects, and reduce toxic and side effects. Payloads with bioactive functions connect to tumor-targeting peptides through linkers. In this review, we explored ongoing clinical work on peptide-drug conjugates targeting various receptors. We discuss the binding mechanisms of tumor-targeting peptides and related receptors, as well as the limiting factors for peptide-drug conjugate-based molecular drug delivery systems.

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.

Patient Selection and Toxicities of PRRT for Metastatic Neuroendocrine Tumors and Research Opportunities

OPINION STATEMENT

Neuroendocrine tumors (NETs) are a heterogenous group of neoplasms characterized by varied biological hallmarks and behavior, ranging from indolent to aggressive. For many decades, somatostatin analogues and few targeted therapies were available for NETs and these therapies had minimal response rates. However, there have been a number of recent treatment advances. Peptide receptor radionuclide therapy (PRRT) is a novel approach to treatment of NETs and has changed the landscape of treatment for NETs. It is a form of targeted therapy in which a radiolabeled somatostatin analogue delivers radiation specifically to tumor cells expressing the somatostatin receptor.

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.

A case of pulmonary carcinoid in pregnancy and review of carcinoid tumours in pregnancy

Carcinoid tumours are rare slow growing tumours which arise from primitive neuroendocrine cells. The effect of the pregnant state on carcinoid tumours and vice versa remains unclear, as does the optimal management of carcinoid tumours during the pregnancy including labour. We report the rare case of a 36 year old primigravida woman with large bilateral pulmonary carcinoid tumours. The patient's disease was minimally symptomatic with no clinical suspicion of carcinoid syndrome. Under close observation, the pregnancy progressed well and the patient proceeded to a spontaneous vaginal delivery of a healthy child. We conduct the the first literature review in 30 years of all reported cases in this area and make suggestions as to assessment and monitoring of cases of carcinoid during pregnancy.

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.

Yttrium-based therapy for neuroendocrine tumors

Peptide receptor radionuclide therapy with (90)Y-peptides is generally well tolerated. Acute side effects are usually mild; some are related to the coadministration of amino acids and others to the radiopeptide itself. Chronic and permanent effects on target organs, particularly kidneys and bone marrow, are generally mild if necessary precautions are taken. The potential risk to kidney and red marrow limits the amount of radioactivity that may be administered. However, when tumor masses are irradiated with adequate doses, volume reduction may be observed. (90)Y-octreotide has been the most used radiopeptide in the first 8 to 10 years of experience.

Peptide receptor radionuclide therapy for advanced neuroendocrine tumors

Peptide receptor radionuclide therapy (PRRT) consists of the systemic administration of a synthetic peptide, labeled with a suitable β-emitting radionuclide, able to irradiate tumors and their metastases via internalization through a specific receptor (usually somatostatin S2), over-expressed on the cell membrane. After almost 2 decades of experience, PRRT, with either (90)Y-octreotide or (177)Lu-octreotate, has established itself to be an efficient and effective therapeutic modality. As a treatment, it is relatively safe up to the known thresholds of absorbed and bio-effective isotope dosages and the renal and hematological toxicity profiles are acceptable if adequate protective measures are undertaken.

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.

Yttrium-labelled peptides for therapy of NET

Peptide receptor radionuclide therapy (PRRT) consists in the systemic administration of a synthetic peptide, labelled with a suitable beta-emitting radionuclide, able to irradiate tumours and their metastases via the internalization through a specific receptor, overexpressed on the cell membrane. After 15 years of experience, we can state that PRRT with (90)Y-labelled peptides is generally well tolerated. Acute side effects are usually mild, some of which are related to the co-administration of amino acids, such as nausea. Others are related to the radiopeptide, such as fatigue or the exacerbation of an endocrine syndrome, which rarely occurs in functioning tumours. Chronic and permanent effects on target organs, particularly the kidneys and the bone marrow, are generally mild if the necessary precautions are taken. Currently, the potential risk to kidney and red marrow limits the amount of radioactivity that may be administered. However, when tumour masses are irradiated with adequate doses, volume reduction may be observed. (90)Y-octreotide has been the most widely used radiopeptide in the first 8-10 years of experience. Unfortunately, all of the published results derive from different and inhomogeneous phase I/II studies. Hence, a direct comparison is virtually impossible to date. Nevertheless, even with these limitations, objective responses are registered in 10-34% of patients. The optimal timing of (90)Y-DOTATOC in the management of somatostatin receptor (SSTR)-positive tumours and the way in which it should be integrated with other treatments have yet to be defined, and prospective phase II/III trials comparing the efficacy and toxicity of different schemes of (90)Y-DOTATOC administration are still warranted.

Peptide receptor therapies in neuroendocrine tumors

Neuroendocrine tumors (NETs) are relatively rare tumors, mainly originating from the digestive system, able to produce bioactive amines and hormones. NETs tend to be slow growing and are often diagnosed when metastatic. The localization of a NETs and the assessment of the extent of disease are crucial for management. Commonly used diagnostic techniques include morphological imaging (ultrasound, computerized tomography, magnetic resonance), and functional imaging (somatostatin receptor scintigraphy, positron emission tomography techniques). Treatment is multidisciplinary and should be individualized according to the tumor type, burden, and symptoms. Therapeutic tools include surgery, interventional radiology, and medical treatments such as somatostatin analogues, interferon, chemotherapy, new targeted drugs and peptide receptor radionuclide therapy (PRRT) with radiolabeled somatostatin analogues. NETs usually over-express somatostatin receptors, thus enabling the therapeutic use of somatostatin analogues, one of the basic tools, able to reduce signs and symptoms of hormone hypersecretion, improve quality of life, and slow tumor growth. PRRT with somatostatin analogues 90Y-DOTATOC and 177Lu-DOTATATE has been explored in NETs for more than a decade. Present knowledge and clinical studies indicate that it is possible to deliver high-absorbed doses to tumors expressing sst2 receptors, with partial and complete objective responses in up to 30% of patients. Side effects, involving the kidney and the bone marrow, are mild if adequate renal protection is used. Moreover, a consistent survival benefit is reported. As NETs may also express cholecystokinin 2, bombesin, neuropeptide Y or vasoactive intestinal peptide receptors even simultaneously, the potential availability and biological stability of radio-analogues will improve the multireceptor targeting of NETs.

Hormonal crises following receptor radionuclide therapy with the radiolabeled somatostatin analogue [177Lu-DOTA0,Tyr3]octreotate

Introduction

Receptor radionuclide therapy is a promising treatment modality for patients with neuroendocrine tumors for whom alternative treatments are limited. The aim of this study was to investigate the incidence of hormonal crises after therapy with the radiolabeled somatostatin analogue [¹⁷⁷Lu-DOTA⁰,Tyr³]octreotate (¹⁷⁷Lu-octreotate).

Materials and methods

All ¹⁷⁷Lu-octreotate treatments between January 2000 and January 2007 were investigated. Four hundred seventy-six patients with gastroenteropancreatic neuroendocrine tumors and three patients with metastatic pheochromocytoma were included for analysis.

Results

Four hundred seventy-nine patients received a total of 1,693 administrations of ¹⁷⁷Lu-octreotate. Six of 479 patients (1%) developed severe symptoms because of massive release of bioactive substances after the first cycle of ¹⁷⁷Lu-octreotate. One patient had a metastatic hormone-producing small intestinal carcinoid; two patients had metastatic, hormone-producing bronchial carcinoids; two patients had vasoactive intestinal polypeptide-producing pancreatic endocrine tumors (VIPomas); and one patient had a metastatic pheochromocytoma. With adequate treatment, all patients eventually recovered.

Conclusion

Hormonal crises after ¹⁷⁷Lu-octreotate therapy occur in 1% of patients. Generally, ¹⁷⁷Lu-octreotate therapy is well tolerated.