Clinical efficacy of octreotide in the treatment of metastatic neuroendocrine tumors. A study by the Italian Trials in Medical Oncology Group

Neuroendocrine tumours of the small intestine

The prevalence of intestinal neuroendocrine tumours, also known as carcinoid tumours, has increased significantly over the past three decades. Tumours of the distal small intestine (midgut) are often indolent, but are characterized by a high potential to metastasize to the small-bowel mesentery and liver. Patients with distant metastases are prone to development of the carcinoid syndrome, a constellation of symptoms which includes flushing, diarrhoea, and valvular heart disease. The carcinoid syndrome is caused by secretion of serotonin and other vasoactive substances into the systemic circulation. Treatment options for metastatic intestinal NETs have expanded in recent years. Of particular importance has been the development of somatostatin-analogue therapies. Somatostatin analogues were originally introduced for palliation of the carcinoid syndrome; however recent clinical trials have demonstrated that they can exert an inhibitory effect on tumour growth. Other novel agents targeting the VEGF and mTOR pathways have recently been evaluated in phase III trials, however their role in the management of small-intestinal NETs remains controversial. This article examines the biological characteristics of small intestinal NETs, summarizes current guidelines on classification, staging and grading, and reviews developments in locoregional and systemic therapy.

Current concepts in diagnosis and perioperative management of carcinoid heart disease

Carcinoid tumors are neuroendocrine tumors with a very unpredictable clinical behavior. In the setting of hepatic metastases, the tumor's release of bioactive substances into the systemic circulation results in carcinoid syndrome: a constellation of symptoms among which cutaneous flushing, gastrointestinal hypermotility, and cardiac involvement are the most prominent. Cardiac manifestations, also known as carcinoid heart disease, are secondary to a severe fibrotic reaction which frequently involves the right-sided valves and may extend towards the subvalvular apparatus leading to valve thickening and retraction. Left-sided involvement is rare and mostly observed in the presence of an interatrial shunt, endobronchial tumor localization, and high tumor activity. Echocardiographic techniques often reveal noncoaptation of the valves, which are fixed in a semiopen position. In patients with advanced lesions and severe valvular dysfunction, surgery is currently the only definitive treatment to potentially improve quality of life and provide survival benefit. Although cardiac surgery has been traditionally reserved for those patients with symptomatic right ventricular failure, a significant trend towards improved surgical outcomes has triggered a more liberal referral for valve replacement. Carcinoid heart disease poses two distinct challenges for the anesthesiologist: carcinoid crisis and low cardiac output syndrome secondary to right ventricular failure. Carcinoid crisis, characterized by flushing, hypotension, and bronchospasm, may be precipitated by catecholamines and histamine releasing drugs used routinely in patients undergoing valve surgery. Although a broader utilization of octreotide have significantly simplified the anesthetic and perioperative management of these patients, a very balanced anesthetic technique is required to identify and manage low cardiac output syndrome.

Phase I study of pasireotide (SOM 230) and everolimus (RAD001) in advanced neuroendocrine tumors

Octreotide and everolimus have demonstrated efficacy in neuroendocrine tumors. Pasireotide is a somatostatin analog with binding affinity to a broader range of somatostatin receptor subtypes than octreotide. We performed a phase I study to evaluate the safety and feasibility of combining pasireotide with everolimus in patients with advanced neuroendocrine tumors. Cohorts of patients with advanced neuroendocrine tumors were treated with escalating doses of pasireotide (600-1200  μg s.c. b.i.d., followed by pasireotide LAR 40-60  mg i.m. monthly) and everolimus (5-10  mg daily). Twenty-one patients were treated. Dose-limiting toxicities consisting of grade 3 rash and grade 3 diarrhea were observed. Twelve patients were safely treated at the maximum protocol-defined dose level of pasireotide LAR 60  mg i.m. monthly and everolimus 10  mg daily. Hyperglycemia was common; other observed toxicities were consistent with the known toxicities of either agent alone. Partial tumor response was observed in one patient; 17 (81%) patients experienced at least some tumor regression as their best response to therapy. In conclusion, pasireotide LAR 60  mg i.m. monthly in combination with everolimus 10  mg daily is feasible and associated with preliminary evidence of antitumor activity in patients with advanced neuroendocrine tumors. Further studies evaluating this combination are warranted.

Carcinoid heart disease

Carcinoid tumors are rare, indolent neuroendocrine tumors that are often associated with a syndrome characterized by episodic flushing, secretory diarrhea, bronchospasm, and hypotension-the carcinoid syndrome. Cardiac involvement occurs in one-half to two-thirds of patients with carcinoid syndrome and is associated with a worse clinical outcome. Carcinoid heart disease is characterized by endocardial plaque-like deposits found predominantly on right-sided heart valves, leading to the combination of valvular stenosis and regurgitation. Left-sided cardiac involvement can also occur in <10% of patients. Somatostatin analogs form the therapeutic cornerstone in the medical management of these patients. Cytotoxic chemotherapy has had only limited success in the treatment of metastatic carcinoid tumors. Hepatic resection or palliative cytoreduction may be of benefit in patients with limited hepatic disease. Hepatic artery embolization is usually applied if a patient is not eligible for surgical debulking. The development and progression of carcinoid heart disease are associated with an unfavorable outcome. In those patients having severe cardiac involvement and well-controlled systemic disease, valve replacement surgery has been found to be an effective treatment that can both relieve intractable symptoms and contribute to improved clinical outcomes.

Chemotherapy in gastroenteropancreatic (GEP) neuroendocrine carcinomas (NEC): a critical view

Neuroendocrine tumors (NET) are classified according to the Ki67 in low-intermediate grade (Ki67<20%) and high grade (Ki67>20%). The NET of the latter group are also known as neuroendocrine carcinoma (NEC), and their prognosis is dismail. While in the former group biotherapy and radionuclide therapy can be proposed, chemotherapy represents the only treatment usually proposed for NEC. Cisplatin/etoposide combination is usually chosen based on the rationale that NEC are clinically similar to small cell lung cancer. However, evidence for cisplatin/etoposide in NEC is poor and controversial, and different schedules and response rate have been published so far. These aspects, combined with the heterogeneous characteristics of NEC, prompt us to have some doubt in considering cisplatin/etoposide as the gold standard. Some evidence exists that carboplatin can be used instead of cisplatin and irinotecan instead of etoposide without reducing efficacy. Furthermore other drugs, as gemcitabine, oxaliplatin or temozolomide can be evaluated in NEC with non-neuroendocrine component or in mixed adenoneuroendocrine carcinomas. NEC are a category of NET that should be deeply studied to verify if the response to cisplatin/etoposide is homogeneous related to the different Ki67, different morphology and/or different primary site.

Treatment options for unresectable neuroendocrine liver metastases

Hepatic metastases develop in 85% of patients with gastroenteropancreatic neuroendocrine tumors. Radical surgery, which involves resection of the primary and liver metastases, is the mainstay of treatment, with 60-70% 5-year survival and 35% 10-year survival rates. However, less than 15% of neuroendocrine tumor liver metastases (NETLMs) are resectable, owing either to multifocality or the inability to preserve sufficient parenchyma following resection. This article deals with the therapeutic modalities available for nonresectable liver metastases, and the therapeutic options available for management of nonresectable NETLMs are discussed. Targeted therapies for NETLMs include hepatic artery embolization, transcatheter arterial chemoembolization, radiolabeled/drug-eluting microspheres, radiofrequency ablation, cryoablation and phenol injection. Hepatic artery embolization/transcatheter arterial chemoembolization is associated with 75-100% symptom relief and an objective tumor response varying from 33 to 80%. Other modalities, such as biotherapy, peptide receptor therapy and chemotherapy, target both the primary and metastatic disease. Their effects on NETLMs as a subgroup have not been evaluated. Various therapeutic options are available for the treatment of unresectable NETLMs. Most offer significant symptomatic relief, with only a few comparative studies showing survival benefit. Most of the available evidence is based on retrospective and prospective case series rather than randomized controlled trials. Well-designed studies on existing treatment modalities and the search for newer therapeutic options are required.

Hitting the target: where do molecularly targeted therapies fit in the treatment scheduling of neuroendocrine tumours?

Neuroendocrine tumours (NETs) are a rare and heterogeneous group of tumours whose incidence is increasing and their prevalence is now greater than that of any other upper gastrointestinal tumour. Diagnosis can be challenging, and up to 25% of patients present with metastatic disease. Following the recent FDA approval of two new molecularly targeted therapies for the treatment of advanced pancreatic NETs (pNETs), the first in 25 years, we review all systemic therapies and suggest where these newer targeted therapies fit in the treatment schedule for these challenging tumours. Clinical trial data relating to the routine use of sunitinib and everolimus in low-intermediate-grade pNETs are summarised alongside newer molecularly targeted agents undergoing clinical assessment in NETs. We particularly focus on the challenge of optimal scheduling of molecularly targeted treatments around existing systemic and localised treatment such as chemotherapy or radiotargeted therapy. We also discuss application of current evidence to subgroups of patients who have not so far been directly addressed such as those with poorer performance status or patients receiving radical surgery who may benefit from adjuvant treatment.

Antitumor effects of somatostatin analogs in neuroendocrine tumors

BACKGROUND

For decades, somatostatin analogs (including octreotide and lanreotide) have been indicated for relief of the symptoms of flushing, diarrhea, and wheezing associated with secretory neuroendocrine tumors (NETs). Recently, it has been suggested that somatostatin analogs may provide direct and indirect antitumor effects in secretory and nonsecretory NETs in addition to symptom control in secretory NETs.

METHODS

A systematic review of MEDLINE was conducted to identify studies that investigated the antitumor effects of octreotide or lanreotide for patients with NETs. Additional studies not published in the peer-reviewed literature were identified by searching online abstracts. Results. In all, 17 octreotide trials and 11 lanreotide trials that included antitumor effects were identified. Partial response rates were between 0% and 31%, and stable disease rates were between 15% and 89%. Octreotide was the only somatostatin analog for which results of a phase III, randomized, placebo-controlled clinical trial that investigated antitumor effects were published. After 6 months of treatment in this randomized phase III trial, stable disease was observed in 67% of patients (hazard ratio for time to disease progression: 0.34; 95% confidence interval: 0.20-0.59; p = .000072).

CONCLUSIONS

In addition to symptom control for NETs, the data support an antitumor effect of somatostatin analogs and suggest that they may slow tumor growth. Long-acting repeatable octreotide has been shown to have an antitumor effect in a randomized phase III trial in midgut NETs, whereas results are pending in a corresponding controlled trial with lanreotide for patients with intestinal and pancreatic primary NETs.

Shortened interval of long-acting octreotide administration is effective in patients with well-differentiated neuroendocrine carcinomas in progression on standard doses

BACKGROUND

In patients with well-differentiated (WD) neuroendocrine tumors (NET), long-acting octreotide (LAR), conventionally administered at a dose of 30 mg every 28 days, has well-documented anti-secretive but limited antiproliferative effects.

AIM

The objective of this study was to evaluate a different schedule of LAR treatment consistent with a shorter interval between administrations (21 days) in WDNET patients with progressive disease at standard-dose interval.

SUBJECTS AND METHODS

Twenty-eight patients followed for diagnosis and therapy of WDNET who had tumor progression during therapy with LAR 30 mg every 28 days were enrolled. Clinical, biological, and objective tumor response was evaluated after LAR 30 mg every 21 days. Time to progression was also evaluated after LAR 30 mg every 21 days and compared to LAR 30 mg every 28 days.

RESULTS

The treatment with LAR 30 mg every 21 days resulted in complete and partial control of clinical symptoms in 40% and 60% of cases, respectively. Circulating neuroendocrine markers were significantly decreased in 30% of cases. A stabilization of disease was obtained in 93% and objective response in 7%. The median time to progression was significantly longer by using the shortened interval of LAR administration as compared to the standard one (30 vs 9 months, p<0.0001). The treatment was safe and well tolerated.

CONCLUSIONS

The shortened schedule of LAR administration was able to re-institute control of clinical symptoms, to decrease level of circulating neuroendocrine markers and to increase time to progression in patients previously escaping from a standard schedule treatment.

Medical treatment of gastroenteropancreatic neuroendocrine tumors

Treatment of the clinically and prognostically heterogeneous neuroendocrine neoplasms (NEN) should be based on a multidisciplinary approach, including surgical, interventional, medical and nuclear medicine-based therapeutic options. Medical therapies include somatostatin analogues, interferon-α, mTOR inhibitors, multikinase inhibitors and systemic chemotherapy. For the selection of the appropriate medical treatment the hormonal activity, primary tumor localization, tumor grading and growth behaviour as well as the extent of the disease must be considered. Somatostatin analogues are mainly indicated in hormonally active tumors for symptomatic relief, but antiproliferative effects have also been demonstrated, especially in well-differentiated intestinal NET. The efficacy of everolimus and sunitinib in patients with pancreatic neuroendocrine tumors (pNET) has been demonstrated in large placebo-controlled clinical trials. pNETs are also chemosensitive. Streptozocin-based chemotherapeutic regimens are regarded as current standard of care. Temozolomide in combination with capecitabine is an alternative that has shown promising results that need to be confirmed in larger trials. Currently, no comparative studies and no molecular markers are established that predict the response to medical treatment. Therefore the choice of treatment for each pNET patient is based on individual parameters taking into account the patient’s preference, expected side effects and established response criteria such as proliferation rate and tumor load. Platin-based chemotherapy is still the standard treatment for poorly differentiated neuroendocrine carcinomas. Clearly, there is an unmet need for new systemic treatment options in patients with extrapancreatic neuroendocrine tumors.

Treatment of liver metastases in patients with neuroendocrine tumors of gastroesophageal and pancreatic origin

Well-to-moderately differentiated neuroendocrine tumors of gastroesophageal and pancreatic origin (GEP-NETs) with liver metastasis are a heterogeneous group of malignancies for which a range of therapeutic options have been employed. Surgical resection of hepatic metastases or hepatic artery embolization may be beneficial in patients with hepatic-predominant metastatic disease. Patients with "carcinoid" syndrome and syndromes associated with functional pancreatic NET (PNET) can be effectively treated with somatostatin analogs. On the other hand, the efficacy of systemic chemotherapy for these patients is limited. A placebo-controlled, double-blind, prospective, and randomized study showed that octreotide LAR improves progression-free survival in patients with advanced midgut functional "carcinoids." In patients with advanced pancreatic NET, randomized, placebo-controlled studies have recently demonstrated that treatment with the tyrosine kinase inhibitor sunitinib or with mTOR inhibitor everolimus is associated with improved progression-free survival. Based on these studies, octreotide LAR, sunitinib, or everolimus are now considered as first-line therapeutic options in patients with advanced NET. Future studies will likely further define the role of these agents in patients with carcinoid liver metastasis and pancreatic NET liver metastasis.

Merkel cell carcinoma

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin. The incidence of this rare tumor is increasing rapidly; the American Cancer Society estimates for 2008 almost 1500 new cases in the USA. Thus, the incidence of MCC will exceed the incidence of cutaneous T-cell lymphoma. Moreover, the mortality rate of MCC at 33% is considerably higher than that of cutaneous melanoma. These clinical observations are especially disturbing as we are only recently beginning to understand the pathogenesis of MCC. For the same reason, the therapeutic approach is often unclear; reliable data are only available for the therapy of locoregional disease.

The treatment of neuroendocrine tumors with long-acting somatostatin analogs: a single center experience with lanreotide autogel

The aim of this retrospective study was to evaluate the efficacy, safety, and tolerability of lanreotide autogel given to metastatic well-differentiated (WD) neuroendocrine tumors (NET) patients observed in our Institute between 2005 and 2008. Patients with metastatic NET referred to our tertiary referral center were given lanreotide autogel 120 mg/month by deep sc injection for a period of at least 24 months. The efficacy was evaluated by the relief of disease symptoms, behavior of tumor markers and response rate in terms of time to tumor progression. Safety and tolerability were evaluated by assessing the onset of adverse events and treatment feasibility. Twenty-three patients (13 males), median age 62 yr (range 32-87) were considered for the study. All patients were affected by WD metastatic NET and had tumor progression in the last 6 months before the enrolment in the study. Median duration of response was 28 months (range 6-50 months). Fourteen patients (60.9%) showed flushing and diarrhea which improved by 85.7% and 55.6%, respectively, bronchoconstrinction and abdominal pain also ameliorated. A complete, partial or no-changed response in the tumor markers behavior was observed, respectively, in 42.9%, 22.9%, and 17.1% of cases. According to RECIST (Response Evaluation Criteria In Solid Tumors) criteria (version 1.1), there were 2 partial regression (8.7%) and 15 stable disease (65.3%); 6 patients (26.0%) progressed. No patient complained from any severe adverse reaction. The results of our study suggest that lanreotide autogel is effective in the symptoms, biochemical markers, and tumor progression control of WD metastatic NET and confirm that the treatment is well tolerated.

The management of neuroendocrine tumours: current and future medical therapy options

Neuroendocrine tumours (NETs) are a genetically diverse group of malignancies that sometimes produce peptides causing characteristic hormonal syndromes. NETs can be clinically symptomatic (functioning) or silent (non-functioning); both types frequently synthesise more than one peptide, although often these are not associated with specific syndromes. Based on data from various sources, the incidence and prevalence of NETs is increasing. The primary treatment goal for patients with NETs is curative, with symptom control and the limitation of tumour progression as secondary goals. Surgery is the only possible curative approach and so represents the traditional first-line therapy. However, as most patients with NETs are diagnosed once metastases have occurred, curative surgery is generally not possible. Patients therefore require chronic postoperative medical management with the aim of relieving symptoms and, in recent years, suppressing tumour growth and spread. Somatostatin analogues, such as octreotide long-acting repeatable (LAR), can improve the symptoms of carcinoid syndrome and stabilise tumour growth in many patients. Results from the PROMID study show that octreotide LAR 30mg is an effective antiproliferative treatment in patients with newly diagnosed, functionally active or inactive, well-differentiated metastatic midgut NETs. An antiproliferative effect can also be achieved with everolimus, and combination therapy with octreotide LAR has shown synergistic antiproliferative activity. In the future, pasireotide, the multi-receptor targeted somatostatin analogue, has the potential to be an effective therapy for de novo or octreotide-refractory carcinoid syndrome and for inhibiting tumour cell proliferation. Peptide receptor radiotherapy with [90]yttrium-DOTATOC or [177]lutetium-DOTATE is also a new interesting treatment option for NETs.

Long-term results of treatment of malignant carcinoid syndrome with prolonged release Lanreotide (Somatuline Autogel)

BACKGROUND

Somatostatin analogues are the mainstay of therapy for malignant carcinoid syndrome. There is clear evidence that the once monthly intramuscular formulation, Octreotide LAR, controls symptoms of carcinoid syndrome, and recent data also suggests an antitumour effect. There is limited data on prolonged release Lanreotide (Somatuline Autogel, Ipsen Pharma Biotech, Signes, France) and no long-term data to date.

AIM

To present long-term results of prolonged release Lanreotide in a large cohort of patients with malignant carcinoid syndrome, assessing clinical and objective response and tolerance.

METHODS

Seventy six patients with metastatic midgut neuroendocrine tumours and carcinoid syndrome were included in this 9-year retrospective study. Clinical response was based on symptom score with radiological assessment based on RECIST (Response Evaluation Criteria In Solid Tumours).

RESULTS

Data were available in 69 patients. Ninety four percent achieved symptomatic response at first follow-up visit. Forty six percent had loss of symptomatic response, but 44% of these achieved control with an increase in dose of prolonged release Lanreotide. Overall, symptoms were well controlled throughout the study period with prolonged release Lanreotide alone in 74% of patients. Twenty six percent required additional treatment despite good initial response. Only 30% demonstrated radiological progression. Eleven patients who were switched from Octreotide LAR had return of symptomatic control. No significant adverse effects were experienced.

CONCLUSIONS

Prolonged release Lanreotide provides good symptomatic control of diarrhoea and flushing as well as tumour stability in patients with malignant carcinoid syndrome.

Somatostatin analogs for the treatment of neuroendocrine tumors

Somatostatin is an important regulator of endocrine and exocrine secretion, affecting the release of many hormones. The effects of somatostatin are mediated through its interaction with one of five somatostatin receptors. Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) express multiple somatostatin receptors, making them excellent potential therapeutic targets. Many trials have shown that treatment with somatostatin analogs is associated with disease stabilization and prolonged survival. More recently, somatostatin analogs have been shown to have antiproliferative effects, thus broadening the scope of their uses. In this review, we update the current data on the treatment of GEP-NETs with somatostatin analogs, with particular emphasis on the results of the PROMID study. In addition, we discuss the current state of knowledge of novel therapies against GEP-NETs, including the use of somatostatin analogs with broader receptor binding profiles, chimeric somatostatin-dopamine molecules, combinations of somatostatin analogs with other active chemotherapy agents, and peptide receptor-targeted radionuclide therapy.

Biological targeted therapies in patients with advanced enteropancreatic neuroendocrine carcinomas

Enteropancreatic (EP) neuroendocrine carcinomas (NECs) represent relatively rare and heterogeneous malignancies. They are the most common group among neuroendocrine tumors (NETs). In most cases they are advanced at diagnosis and slow-growing, therefore conditioning a better prognosis compared with non neuroendocrine carcinomas from the same sites. No standard medical therapy exists, except for somatostatin analogs in functioning tumors, and octreotide LAR in functioning or non functioning well differentiated NECs from small bowel. Several systemic therapeutic options exist, including chemotherapy, somatostatin analog, interferon, peptide receptor radionuclide therapy (PRRT), and molecular targeted drugs. Among them some therapies have specific biological tumor targets and can be defined as "biological targeted therapies". This review focuses on the status of EP NECs targeted therapies in the light of recent advances. Somatostatin receptors (SSTRs) are the first therapeutic target detected in EP NECs. Through them SS analogs and PRRT act, producing symptomatic, biochemical, and, to a lesser extent, antiproliferative effects. New SS analogs, covering a higher number of SSTR subtypes, were developed, including pasireotide (SOM230), which controls 25% of carcinoid syndromes resistant to full dose octreotide LAR. Chimeric analogs, which bind SSTR2/SSTR5 and dopamine-2 receptor subtype (D2), are in preclinical phase of development. Among the numerous molecular targeted agents investigated in NETs, mTOR inhibitors and VEGF/VEGFR/PDGFR inhibitors are in most advanced clinical phase of investigation. In particular, everolimus, sunitinib, and bevacizumab are all studied in phase III trials. Both everolimus and sunitinib produced significant survival benefit versus placebo in advanced progressing well-differentiated pancreatic NECs. Sunitinib data have been presented at the last ASCO in June 2010, and everolimus data will be presented at next ESMO in September 2010.

Management of neuroendocrine tumors: current and future therapies

Neuroendocrine tumors (NETs) are a genetically diverse group of malignancies that sometimes produce peptides that cause characteristic hormonal syndromes. NETs can be clinically symptomatic (functioning) or silent (nonfunctioning); both types frequently synthesize more than one peptide, although often these are not associated with specific syndromes. Based on data from various sources, the incidence and prevalence of NETs is increasing. The primary treatment goal for patients with NETs is curative, with symptom control and the limitation of tumor progression as secondary goals. Surgery is the only possible curative approach and so represents the traditional first-line therapy. However, as most patients with NETs are diagnosed once metastases have occurred, curative surgery is generally not possible. Patients therefore require chronic postoperative medical management with the aim of relieving symptoms and, in recent years, suppressing tumor growth and spread. Somatostatin analogues, such as octreotide long-acting repeatable (LAR), can improve the symptoms of carcinoid syndrome and stabilize tumor growth in many patients. Results from the placebo-controlled, double-blind, prospective randomized study on the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors (PROMID study) demonstrate that octreotide LAR 30 mg is an effective antiproliferative treatment in patients with newly diagnosed, functionally active or inactive, well-differentiated metastatic midgut NETs. An antiproliferative effect can also be achieved with everolimus, and combination therapy with octreotide LAR has shown synergistic antiproliferative activity. Sunitinib, a tyrosine kinase inhibitor, is active in pancreatic NETs. In the future, pasireotide, the multireceptor targeted somatostatin analogue, has the potential to be an effective therapy for de novo or octreotide-refractory carcinoid syndrome and for inhibiting tumor cell proliferation. Peptide receptor radiotherapy with ⁹⁰Yttrium-DOTATOC or ¹⁷⁷Lutetium-DOTATE is also a new interesting treatment option for NETs.

Antiproliferative effect of somatostatin analogs in gastroenteropancreatic neuroendocrine tumors

Somatostatin analogs were initially developed for the control of hormonal syndromes associated with neuroendocrine tumors (NETs). In recent years, accumulating data has supported their role as antiproliferative agents, capable of stabilizing tumor growth in patients with metastatic neuroendocrine malignancies, including carcinoid and pancreatic endocrine tumors. A phase III, randomized, placebo-controlled trial has now demonstrated that octreotide long-acting repeatable (LAR) 30 mg can significantly prolong time to tumor progression among patients with metastatic midgut NETs regardless of functional status, chromogranin A level or age. In addition to significantly lengthening time to tumor progression in the overall study population, subset analysis suggests that patients with low tumor burden are most likely to experience disease stabilization with octreotide LAR 30 mg, supporting the early use of octreotide LAR in patients with metastatic disease. Further research efforts are underway to evaluate the use of somatostatin analogs as antiproliferative agents in other types of gastroenteropancreatic-NETs. Ongoing studies are also evaluating novel somatostatin analogs and somatostatin analogs in combination with other anti-tumor therapies.

Recent trends in the treatment of well-differentiated endocrine carcinoma of the small bowel

Well-differentiated endocrine carcinomas of the small bowel are fairly rare neoplasms that present many clinical challenges. They secrete peptides and neuroamines that may cause carcinoid syndrome. However, many are clinically silent until late presentation with major effects. Initial treatment aims to control carcinoid syndrome with somatostatin analogs. Even if there is metastatic spread, surgical resection of the primitive tumor should be discussed in cases of retractile mesenteritis, small bowel ischemia or subocclusive syndrome in order to avoid any acute complication, in particular at the beginning of somatostatin analog treatment. The choice of treatment depends on the symptoms, general health of the patient, tumor burden, degree of uptake of radionuclide, histological features of the tumor, and tumor growth. Management strategies include surgery for cure (which is rarely achieved) or for cytoreduction, radiological interventions (transarterial embolization or radiofrequency ablation), and chemotherapy (interferon and somatostatin analogs). New biological agent and radionuclide targeted therapies are under investigation. Diffuse and non-evolving lesions should also be simply monitored. Finally, it has to be emphasized that it is of the utmost importance to enroll these patients with a rare disease in prospective clinical trials assessing new therapeutic strategies.

Minute liver metastases from a rectal carcinoid: A case report and review

We here report a 43-year-old male patient with minute liver metastases from a rectal carcinoid. Hepatic nodules were diagnosed during surgery, although they were not diagnosed by preoperative computed tomography or ultrasound examination. The rectal carcinoid was resected together with liver metastases and the patient has had no disease recurrence for 5 years following postoperative treatment of hepatic arterial infusion chemotherapy (HAIC) using 5-fluorouracil (5-FU) and oral administration of 1-hexylcarbamoyl-5-fluorouracil (HCFU). In 2003, a health check examination indicated presence of occult blood in his stool. Barium enema study revealed a rectal tumor in the lower rectum and colonoscopy showed a yellowish lesion with a size of 30 mm in diameter. Pathological examination of the biopsy specimen indicated that the rectal tumor was carcinoid. Although preoperative imaging examinations failed to detect liver metastases, 2 min nodules were found on the surface of liver during surgery. A rapid pathological examination revealed that they were metastatic tumors from the rectal carcinoid. Low anterior resection was performed for the rectal tumor and the pathological report indicated that there were 4 metastatic lymph nodes in the rectal mesentery. The patient received treatment by HAIC using 5-FU plus oral administration of HCFU and survived for 5 years.

We also review world-wide current treatments and their efficacy for hepatic metastases of carcinoid tumors.

Somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine tumours, current aspects and new perspectives

Gastroenteropancreatic neuroendocrine tumours (GEP NETs) are rare tumours that present many clinical features.They secrete peptides and neuroamines that cause distinct clinical syndromes, including carcinoid syndrome. However, many are clinically silent until late presentation with mass effects.In 2000 the WHO developed a new classification which gives a better description of the characteristics and biological behaviour of the tumour.Surgical resection is the treatment of first choice for a patient with a GEP NET. In metastatic disease multiple therapeutic approaches are possible. In these cases the goal is to improve quality of life and to extent survival.GEP NETs express somatostatin receptors (SSTRs), which are bound by somatostatin (SST) or its synthetic analogues, although the subtypes and number of SSTRs expressed is very variable.Somatostatin analogues are used frequently to control hormone-related symptoms while their anti-neoplastic activity, even if it has not been widely studied and the regarding data are discordant, seems to result prevalently in tumour stabilisation.A few patients who fail to respond or cease to respond to standard SST analogues treatment seem to have a response to higher doses of these drugs.The use of higher doses of somatostatin analogues or the development of new subtype selective agonists and chimaeric somatostatin analogues, or pan-somatostatin will probably improve the clinical management of these patients.This review provides an update on the use of somatostatin analogues in the management of GEP NETs and discusses novel clinical strategies based on SSTR 2 gene transfer therapy.

90Y-edotreotide for metastatic carcinoid refractory to octreotide

PURPOSE

Metastatic carcinoid is an incurable malignancy whose symptoms, such as diarrhea and flushing, can be debilitating and occasionally life-threatening. Although symptom relief is available with octreotide, the disease eventually becomes refractory to octreotide, leaving no proven treatment options. The goal of this study was to evaluate the clinical effect of using (90)Y-edotreotide to treat symptomatic patients with carcinoid tumors.

PATIENTS AND METHODS

Patients enrolled had metastatic carcinoid, at least one sign/symptom refractory to octreotide, and at least one measurable lesion. Study treatment consisted of three cycles of 4.4 GBq (120 mCi) (90)Y-edotreotide each, once every 6 weeks.

RESULTS

Ninety patients were enrolled in the study. Using Southwest Oncology Group tumor response criteria, 67 (74.%) of 90 patients (95% CI, 65.4% to 83.4%) were objectively stable or responded. A statistically significant linear trend toward improvement was demonstrated across all 12 symptoms assessed. Median progression-free survival was significantly greater (P = .03) for the 38 patients who had durable diarrhea improvement than the 18 patients who did not (18.2 v 7.9 months, respectively). Adverse events (AEs) were reported in 96.7% (87 of 90) of patients. These AEs consisted primarily of reversible GI events (76 of 90), which could be caused in part by concomitant administration of amino acid solution given to reduce radiation exposure to the kidneys. There was one case each of grade 3 oliguria and grade 4 renal failure, each lasting 6 days.

CONCLUSION

(90)Y-edotreotide treatment improved symptoms associated with malignant carcinoid among subjects with no treatment alternatives. Treatment was well-tolerated and had an acceptable expected AE profile.

Role of Somatostatin Analogs in the Management of Neuroendocrine Tumors

Neuroendocrine tumors are rare neoplasms. During the last two decades, somatostatin analogs, exerting their activity through both receptor binding and enzymatic inhibition mechanisms, have been a key option in the management of neuroendocrine tumors. The treatment of neuroendocrine tumors with high doses of somatostatin analogs determined high rates of tumor stabilization, but the dose-response of somatostatin analogs on symptomatic relief and stabilization of tumor growth remains unpredictable. Several studies have indicated a higher efficacy of somatostatin analogs in well-differentiated, low-grade malignancy tumors that express a high density of somatostatin receptors. Synthesis of new, more effective molecules, with different pharmacokinetic profiles, receptor affinity and binding stability, will ease the clinician's tasks and improve patient expectancies in terms of survival and quality of life. Further studies are needed to clarify mechanisms underlying the better antiproliferative effect of higher doses of somatostatin analogs and to determine the optimum dose to saturate specific receptor subtypes

Pancreatic islet cell carcinoma presenting with concurrent Cushing's and Zollinger-Ellison syndromes: case series and literature review

Cushing's syndrome and Zollinger-Ellison syndrome occur occasionally as a result of neuroendocrine cancers. The concurrence of the two syndromes has been considered to confer a poor clinical and therapeutic outcome. In this study, we are reviewing two patients with pancreatic islet cell carcinomas and with both Zollinger-Ellison and Cushing's syndromes, one followed up for more than 5 years, and the other still receiving therapy, 5 years since diagnosis. A literature review showed that surgery has limited utility as the majority of these patients had metastases at the time of diagnosis. Proton-pump inhibitors, ketoconazole, and somatostatin antagonists have a major role in controlling symptoms. Interferon and systemic chemotherapeutic agents play a role in the management of metastatic and fast-growing cases. Chemoembolization and bland embolization show encouraging results in controlling liver metastases. The latter was used effectively and more than once in the two patients presented herein. On the basis of recent molecular genetics studies, target therapy may be helpful, however, ongoing trials will define it's utility. As the data confers a worse prognosis versus other pancreatic neuroendocrine tumors, the relatively favorable outcome of the two patients reported herein may reflect the impact of multiple therapeutic modalities.

Long-term results of patients with malignant carcinoid syndrome receiving octreotide LAR

BACKGROUND

Octreotide LAR is an established treatment for malignant carcinoid syndrome. However, studies with large number of patients and long follow-up are lacking.

AIM

To present long-terms results with octreotide LAR, assessing duration of clinical and objective response and treatment tolerance, in a large, homogeneous cohort of patients with malignant carcinoid syndrome.

METHODS

A total of 108 patients with metastatic midgut neuroendocrine tumours were included in this 8-year study. Clinical evaluation was based on a symptom score. Radiological assessment was based on RECIST (Response Evaluation Criteria In Solid Tumours) criteria.

RESULTS

Of the 108 patients, 24% had a sustained symptomatic response. In the remaining patients, loss of symptomatic response with the initial dose was noted within 3-60 months. In 17% of them, symptoms were controlled by just an increase of octreotide LAR dose, whilst the other patients required additional treatment. Overall, in 45.3% of patients, symptoms were well controlled during the study period with only octreotide LAR, and no additional treatment was required. No significant adverse effects were noted.

CONCLUSIONS

Octreotide LAR treatment provides a sustained symptomatic response in about half of the patients with malignant carcinoid syndrome and contributes to disease stabilization for a longer period than previously described.

Placebo-controlled, double-blind, prospective, randomized study on the effect of octreotide LAR in the control of tumor growth in patients with metastatic neuroendocrine midgut tumors: a report from the PROMID Study Group

PURPOSE

Somatostatin analogs are indicated for symptom control in patients with gastroenteropancreatic neuroendocrine tumors (NETs). The ability of somatostatin analogs to control the growth of well-differentiated metastatic NETs is a matter of debate. We performed a placebo-controlled, double-blind, phase IIIB study in patients with well-differentiated metastatic midgut NETs. The hypothesis was that octreotide LAR prolongs time to tumor progression and survival.

PATIENTS AND METHODS

Treatment-naive patients were randomly assigned to either placebo or octreotide LAR 30 mg intramuscularly in monthly intervals until tumor progression or death. The primary efficacy end point was time to tumor progression. Secondary end points were survival time and tumor response. This report is based on 67 tumor progressions and 16 observed deaths in 85 patients at the time of the planned interim analysis.

RESULTS

Median time to tumor progression in the octreotide LAR and placebo groups was 14.3 and 6 months, respectively (hazard ratio [HR] = 0.34; 95% CI, 0.20 to 0.59; P = .000072). After 6 months of treatment, stable disease was observed in 66.7% of patients in the octreotide LAR group and 37.2% of patients in the placebo group. Functionally active and inactive tumors responded similarly. The most favorable effect was observed in patients with low hepatic tumor load and resected primary tumor. Seven and nine deaths were observed in the octreotide LAR and placebo groups, respectively. The HR for overall survival was 0.81 (95% CI, 0.30 to 2.18).

CONCLUSION

Octreotide LAR significantly lengthens time to tumor progression compared with placebo in patients with functionally active and inactive metastatic midgut NETs. Because of the low number of observed deaths, survival analysis was not confirmatory.

Changing the clinical picture of challenging tumors: tales becoming reality?

The treatment of neoplastic diseases has become increasingly dependent on tumor biology and is focused on targeted therapy. Understanding complex networks of intracellular signaling pathways, blockades of specific targets and a myriad of other approaches has brought new fuel to the battle against many types of cancer. Unfortunately, the degree of benefit achieved in this new era of cancer treatment has not been distributed homogeneously among the different disease types. Neoplasms with lower incidence rates, but that are also highly challenging, are not consistently given due attention by research leaders. This article aims to evaluate new insights and potential gains obtained with new therapies in a particular group of tumors: those rarely debated in clinical practice, but which still pose a considerable challenge to clinical oncology.

Medullary thyroid cancer: management guidelines of the American Thyroid Association

BACKGROUND

Inherited and sporadic medullary thyroid cancer (MTC) is an uncommon and challenging malignancy. The American Thyroid association (ATA) chose to create specific MTC Clinical Guidelines that would bring together and update the diverse MTC literature and combine it with evidence-based medicine and the knowledge and experience of a panel of expert clinicians.

METHODS

Relevant articles were identified using a systematic PubMed search and supplemented with additional published materials. Evidence-based recommendations were created and then categorized using criteria adapted from the United States Preventive Services Task Force, Agency for Healthcare Research and Quality.

RESULTS

Clinical topics addressed in this scholarly dialog included: initial diagnosis and therapy of preclinical disease (including RET oncogene testing and the timing of prophylactic thyroidectomy), initial diagnosis and therapy of clinically apparent disease (including preoperative testing and imaging, extent of surgery, and handling of devascularized parathyroid glands), initial evaluation and treatment of postoperative patients (including the role of completion thyroidectomy), management of persistent or recurrent MTC (including the role of tumor marker doubling times, and treatment of patients with distant metastases and hormonally active metastases), long-term follow-up and management (including the frequency of follow-up and imaging), and directions for future research.

CONCLUSIONS

One hundred twenty-two evidence-based recommendations were created to assist in the clinical care of MTC patients and to share what we believe is current, rational, and optimal medical practice.

Nonfunctioning neuroendocrine pancreatic tumors: our experience and management

BACKGROUND AND PURPOSE

We present our experience in the treatment of nonfunctioning neuroendocrine pancreatic tumors (NFNPTs) to define the clinical and pathological characteristics and to suggest proper management.

METHODS

The records of 17 patients with NFNPTs operated on between 1998 and 2008 were retrospectively reviewed, and all tumors were classified clinicopathologically as benign, uncertain, and malignant, based on the World Health Organization (WHO) classification of neuroendocrine tumors.

RESULTS

There were four benign, six uncertain, and seven malignant NFNPTs. The most frequent symptoms were abdominal pain (five patients) and obstructive jaundice (one patient). Most of these symptomatic patients had malignant tumors. Mean tumor size of benign, uncertain, and malignant tumors were 1.0 +/- 0.3, 3.2 +/- 1.6, and 5.3 +/- 2.4 cm, respectively. Metastatic lesions of malignant tumors were lymph node (six patients), liver (four patients), and adrenal gland (one patient). Six of seven patients with malignant tumors underwent curative rejection. There were recurrences in four of six patients with curatively rejected malignant tumors. Two patients underwent more rejection, three patients received systemic chemotherapy, and two patients underwent radiofrequency ablation and transcatheter arterial chemoembolization for liver metastases. Survival of patients with malignant tumors was significantly shorter than that of patients with benign and uncertain tumors. However, three patients with malignant tumors had long survival of more than 3 years, even with metastases or recurrences.

CONCLUSIONS

Aggressive surgical resection should be performed in patients with resectable NFNPTs, even with metastases. Even when a tumor was unresectable or there were recurrences, long-time palliation could be achieved by a multidisciplinary approach.

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.

Treatment of advanced disease in patients with well-differentiated neuroendocrine tumors

Well-differentiated neuroendocrine tumors (NETs), which are also referred to as well-differentiated endocrine carcinoma according to WHO terminology, are usually slow-growing cancers, even when they exhibit gross local invasion and/or metastases. The survival of patients with metastatic NET is often measured in years to decades. Once NET progresses or becomes symptomatic the patient's prognosis is poor. An important challenge for clinicians is to distinguish at an early stage those patients who will die with the disease, from those who will succumb because of it, so that the appropriate level of care can be administered. Reliable genomic predictors could provide substantial advancements in prognosis and, possibly, treatment; however, such markers are currently unavailable. Early literature on the treatment of NETs is confounded by a lack of formal objective response criteria. Somatostatin analogs can control symptoms and can stabilize some slow-growing tumors, but rarely result in tumor regression. Surgery is curative in only a minority of patients, and systemic chemotherapy is minimally effective. Advances in the understanding of tumor biology have led to the identification of important cellular processes involved in the pathogenesis of NETs, and agents that target these processes have now entered clinical trials. We will discuss the data on therapies currently used to treat well-differentiated NETs, and the strategies being used in clinical trials.

Merkel cell carcinoma: molecular pathogenesis, clinical features and therapy

Merkel cell carcinoma (MCC) is a highly aggressive neuroendocrine carcinoma of the skin. The incidence of this rare tumor is increasing rapidly; the American Cancer Society estimates for 2008 almost 1500 new cases in the U.S. Thus, the incidence of MCC will exceed the incidence of cutaneous T-cell lymphoma. Moreover, the mortality rate of MCC with 33% is considerably higher than that of cutaneous melanoma. These clinical observations are especially disturbing as we are only recently beginning to understand the pathogenesis of MCC. For the same reason, the therapeutic approach is often unclear; reliable data are only available for the therapy of locoregional disease.

Pharmacotherapy of neuroendocrine cancers

BACKGROUND

Neuroendocrine tumors (NETs) of the diffuse neuroendocrine cell system often present a considerable diagnostic and therapeutic challenge.

METHODS

We have reviewed the literature on NET treatment between 1979 and 2008 (PubMed search: carcinoid or neuroendocrine tumor/tumour + treatment or management), and summarized current therapeutic options and recommendations.

RESULTS

The majority of tumors are diagnosed at a stage that the only curative treatment, radical surgical intervention, is no longer an option. Biotherapy with somatostatin analogs is currently the most efficient treatment to achieve palliation. The interferon class of agents may have a role in selected individuals but substantial adverse events often limit their use. Conventional chemotherapy has minimal efficacy but may have some utility in undifferentiated or highly proliferating neuroendocrine carcinomas and pancreatic NETs. Hepatic metastases, depending on size, location and number, may be amenable to surgical resection, embolization or radio-frequency ablation. Peptide receptor targeted radiotherapy may lead to reduction in tumor size but in most circumstances has a tumor-stabilizing effect. A variety of antiangiogenesis and growth factor-targeted agents have been evaluated but to date the results have failed to meet expectations. Thus, long-acting somatostatin analogs remain the only effective pharmacotherapeutic option that improves symptomatology and quality of life with minimal adverse effects.

Histologic grade is correlated with outcome after resection of hepatic neuroendocrine neoplasms

BACKGROUND

The behavior of neuroendocrine neoplasms is poorly defined, and predictors of outcome after surgical resection have yet to be identified. Consequently, guidelines for treatment remain unclear. Current pathologic classification systems do not permit meaningful discrimination of hepatic neuroendocrine neoplasms.

METHODS

The authors reviewed prospectively maintained databases from 2 institutions of patients who underwent hepatic resection for neuroendocrine neoplasms between 1990 and 2006. Patient, tumor, and operative characteristics were analyzed to identify factors associated with overall survival, progression-free survival, and symptom control. Hepatic neoplasms were stratified by using a 3-tier pathologic classification system based on the number of mitotic figures and the presence of tumor necrosis that was recently validated for pancreatic neuroendocrine neoplasms.

RESULTS

Seventy patients were identified from the databases. Low-grade, intermediate-grade, and high-grade neoplasms were identified in 53%, 37%, and 10% of patients, respectively. After a median follow-up of 51 months, the median overall survival for all patients was 91 months, and it was 108 months when 7 patients with high-grade neuroendocrine carcinomas were excluded. Progressive disease was eventually observed in 81% of patients, and the median progression-free survival was 17 months. The median time to the onset of symptoms was 39 months for patients who presented with hormonal symptoms and 80 months for all patients. Histologic grade was associated with poorer overall and progression-free survival.

CONCLUSIONS

When performed in a context of aggressive multimodality therapy, long-term outcomes after partial hepatectomy for hepatic neuroendocrine neoplasms were favorable; however, disease progression was eventually observed in the majority of patients. Several oncologic variables were associated with significant differences in survival after resection. A novel pathologic classification system appears to enhance prognostic stratification of patients with hepatic neuroendocrine neoplasms.

The role of somatostatin analogues in the treatment of neuroendocrine tumours

Neuroendocrine tumours belong to a heterogeneous family of neoplasms, originating in endocrine glands (such as the pituitary, parathyroid or the neuroendocrine adrenal glands), in endocrine islets (within the thyroid or pancreas) as well as in endocrine cells dispersed between exocrine cells throughout the digestive or respiratory tracts. The clinical behaviour of neuroendocrine tumours is variable; they may be functioning or not functioning, ranging from well-differentiated slow growing neuroendocrine tumours to poorly differentiated neuroendocrine tumours, which are highly aggressive malignant tumours. The development of somatostatin analogues as important diagnostic and treatment tools have revolutionised the clinical management of patients with neuroendocrine tumours. However, although symptomatic relief and stabilisation of tumour growth for various periods of time are observed in many patients treated with somatostatin analogues, tumour regression is rare. Development of new somatostatin analogues and new drug combination therapies should further improve the clinical management of these patients.

Neuroendocrine tumors of the gastrointestinal tract: a decade of experience at the Princess Margaret Hospital

OBJECTIVES

Neuroendocrine tumors (NETs) are uncommon malignancies with variable natural history and often indolent biological behavior. Over the past decade, novel treatment approaches have been developed. The purpose of this study was to review the experience at the Princess Margaret Hospital in treating patients with NET over the past decade.

METHODS

The Princess Margaret Hospital Cancer Registry identified 193 patients with NET of the gastrointestinal tract or unknown primary who had their initial visits between 1992 and 2002. A retrospective chart review was performed.

RESULTS

The median follow-up duration was 22.6 months. Demographics of the entire cohort of 193 patients were: male, 53%; mean age, 56 years; age-adjusted Charlson score 0, 71%. Anatomic distribution of the primary location revealed that 35% were from the foregut, 40% from midgut, 11% from hindgut, and 14% from unknown origin. Pathological distribution demonstrated that 72% were NET/carcinoids, 21% were islet cell tumors, and 6% were small cell carcinomas. At presentation, 53% of patients had distant metastases and 46% had loco-regional disease. Curative surgery was performed in 35% of the cohort, whereas radiotherapy and chemotherapy of any intent were delivered to 13% and 34%, respectively. For the entire cohort, 5-year survival was 58% (95% confidence interval, 50%-67%). In multivariate analysis, age, location of primary, and curative intent of surgery were independent predictors of survival. Of patients who underwent curative surgery, 86% were alive at 5 years.

CONCLUSION

Patients with NET who are offered curative surgery have a good outcome. Distant metastases are commonly found at presentation and portend a worse prognosis. These patients should be evaluated by a multidisciplinary team regarding new approaches to surgery and other therapies.

Histological, CT, and intraoperative ultrasound appearance of hepatic tumors previously treated by laparoscopic radiofrequency ablation

PURPOSE

The purpose of this paper is to compare intraoperative biopsy results of previously ablated liver tumors with their preoperative computed tomography (CT) and intraoperative laparoscopic ultrasound (LUS) appearances in patients undergoing repeat radiofrequency ablation (RFA).

METHODS

Seventy repeat RFA procedures were performed in 59 (13%) patients. Laparoscopically, suspected recurrent and stable appearing foci were biopsied using an 18 G biopsy gun. Preoperative CT and LUS appearances of the previously ablated lesions were compared with core biopsy results.

RESULTS

There were 33 patients with colorectal cancer, 11 with hepatocellular cancer, 8 with neuroendocrine tumors, and 7 with other tumor types. Two hundred lesions were treated by RFA in these 70 repeat ablations. Suspected recurrent tumor foci were enhanced on CT and produced a more finely stippled echo pattern on LUS. Biopsy confirmed recurrent tumor in 72 of 84 such lesions. Previously ablated foci had a CT appearance of a hypodense, nonenhancing lesion without evidence of adjacent enhancing foci. Laparoscopic ultrasound appearance was of a hypoechoic lesion with a coarse internal pattern with the tracks of the ablation catheter probes often still visible. Biopsy found necrotic tissue in 21 of 22 such lesions appearing radiologically to be without recurrence. Biopsy of an ablated focus adjacent to an area of suspected recurrence showed necrotic tissue in 17 of 22 lesions and viable cancer in 5.

CONCLUSION

CT and LUS appearance of previously ablated foci showed good correlation with core biopsies. CT scan is reliable in following RFA lesions, without the need for routine biopsy. LUS reliably distinguished recurrent from ablated lesions in patients undergoing repeat ablation.

Treatment of gastroenteropancreatic neuroendocrine tumors

Neuroendocrine tumors are rare; thus, individual experience with the diagnosis and treatment of these tumors is mostly low, except in specialized centers. For histological diagnosis, standards have been described recently. Pathological classification and clinical staging influence diagnostic and therapeutic decisions. This chapter aims at demonstrating the importance of pathological and clinical classification of neuroendocrine tumors on therapeutic decisions, indicating the appropriate therapy for different stages of the disease. Surgical therapy will be discussed shortly, including palliative surgical strategies. However, the focus of the manuscript is medical therapy. Biotherapy, its effects, and remaining uncertainties are presented as well as different chemotherapeutic schemes. Finally, new options of palliative medical therapies like kinase inhibitors and anti-angiogenetic drugs will be discussed.

Systemic and Regional Nonsurgical Therapy—What Is the Optimal Strategy for Metastatic Neuroendocrine Cancer?

A multidisciplinary team is essential for the optimal management of patients with metastatic neuroendocrine tumors. In this article, the systemic and regional nonsurgical therapeutic options for metastatic neuroendocrine cancers are discussed. In particular, the roles of biotherapy, chemotherapy, and hepatic artery embolization/chemoembolization are reviewed. A proposed treatment algorithm is provided with the aim of providing clinicians with a useful framework for managing these challenging patients. Finally, the rationale for promising investigational therapies is described.

Islet Cell Carcinoma: Neuroendocrine Tumors of the Pancreas and Periampullary Region

Most patients who have islet cell tumors, except those who have insulinomas, present with locally advanced or metastatic disease. In contrast with patients who have adenocarcinoma of the pancreas, those who have islet cell carcinomas can achieve long-term survival even if their disease is advanced. Liver-directed therapies, somatostatin analogs, and interferon are not curative but can be used to relieve tumor-associated symptoms. Similarly, palliative chemotherapy has been used with limited success. Advances in our understanding of the molecular mechanisms underlying tumor progression have translated into intense interest in biologically based strategies to treat this disease.

Evaluation of IGF-I levels during long-term somatostatin analogs treatment in patients with gastroenteropancreatic endocrine tumors

Previous experiments reported desensitization to SS action in rat anterior pituitary cells and cell lines. The aim of the study was to verify whether the lack of desensitization to SS analogs (SSa) observed in acromegalic patients was also present in subjects with normal hypothalamic-pituitary function. The effect of chronic treatment with octreotide long-acting release (o-LAR, 10-30 mg/28 days) on IGF-I levels was then evaluated in 23 patients with gastroenteropancreatic (GEP) endocrine tumors (8 gastrinomas, 6 carcinoids, and 9 functioning pancreatic tumors). Serum IGF-I, clinical symptoms, plasma chromogranin-A (CgA) and markers of hepatic synthesis were evaluated before and after a short-term period in all the patients (median 4.5 months), after a medium-term period in 12 (median 18 months) and after a long-term follow-up period in 9 of them (median 48 months). Mean IGF-I levels decreased from 17.3+/-7.0 to 12.8+/-6.2 nmol/l in the short-term (p<0.005) being reduced from baseline concentrations in 87% and under the normal range for age in 35% of patients. Afterwards, they always remained stable both in the medium- and long-term periods, still being low in 3/12 and 2/9 patients, respectively. No alterations in biochemical markers of liver function were found either before or during therapy. No correlation between IGF-I levels, CgA concentrations and/or clinical definitive outcome was observed. In conclusion, the study demonstrated that: a) similarly to that observed in acromegalic patients, chronic o-LAR treatment did not induce desensitization of pituitary SS receptors (SSR) in humans with intact hypothalamic-pituitary axis, and b) in patients with GEP endocrine tumors, GH/IGF-I inhibition did not contribute to SSa efficacy.