Management of neuroendocrine tumors: current and future therapies

References

• Yao JC, Hassan M, Phan A et al. One hundred years after ‘carcinoid’: epidemiology of and prognostic factors for neuroendocrine tumors in 35,825 cases in the United States. J. Clin. Oncol.26(18), 3063–3072 (2008).
   PubMed Web of Science ®Google Scholar
• Hauso O, Gustafsson BI, Kidd M et al. Neuroendocrine tumor epidemiology: contrasting Norway and North America. Cancer113(10), 2655–2664 (2008).
   PubMed Web of Science ®Google Scholar
• Maggard MA, O’Connell JB, Ko CY. Updated population-based review of carcinoid tumors. Ann. Surg.240(1), 117–122 (2004).
   PubMed Web of Science ®Google Scholar
• Modlin IM, Lye KD, Kidd M. A 5-decade analysis of 13,715 carcinoid tumors. Cancer97(4), 934–959 (2003).
   PubMed Web of Science ®Google Scholar
• Metz DC, Jensen RT. Gastrointestinal neuroendocrine tumors: pancreatic endocrine tumors. Gastroenterology135(5), 1469–1492 (2008).
   PubMed Web of Science ®Google Scholar
• Ramage JK, Davies AH, Ardill J et al. Guidelines for the management of gastroenteropancreatic neuroendocrine (including carcinoid) tumours. Gut54(Suppl. 4), iv1–iv16 (2005).
   PubMed Web of Science ®Google Scholar
• Pirker RA, Pont J, Pohnl R, Schutz W, Griesmacher A, Muller MM. Usefulness of chromogranin A as a marker for detection of relapses of carcinoid tumours. Clin. Chem. Lab. Med.36(11), 837–840 (1998).
   PubMedGoogle Scholar
• Korse CM, Bonfrer JM, Aaronson NK, Hart AA, Taal BG. Chromogranin A as an alternative to 5-hydroxyindoleacetic acid in the evaluation of symptoms during treatment of patients with neuroendocrine tumors. Neuroendocrinology89(3), 296–301 (2009).
   PubMedGoogle Scholar
• Bajetta E, Ferrari L, Martinetti A et al. Chromogranin A. Neuron specific enolase, carcinoembryonic antigen, and hydroxyindole acetic acid evaluation in patients with neuroendocrine tumors. Cancer86(5), 858–865 (1999).
   PubMed Web of Science ®Google Scholar
• Yao JC, Lombard-Bohas C, Baudin E et al. Daily oral everolimus activity in patients with metastatic pancreatic neuroendocrine tumors after failure of cytotoxic chemotherapy: a Phase II trial. J. Clin. Oncol.28(1), 69–76 (2009).
   PubMedGoogle Scholar
• Schnirer, II, Yao JC, Ajani JA. Carcinoid – a comprehensive review. Acta Oncol.42(7), 672–692 (2003).
   PubMed Web of Science ®Google Scholar
• Eriksson B, Kloppel G, Krenning E et al. Consensus guidelines for the management of patients with digestive neuroendocrine tumors – well-differentiated jejunal-ileal tumor/carcinoma. Neuroendocrinology87(1), 8–19 (2008).
   PubMed Web of Science ®Google Scholar
• Pape UF, Berndt U, Muller-Nordhorn J et al. Prognostic factors of long-term outcome in gastroenteropancreatic neuroendocrine tumours. Endocr. Relat. Cancer15(4), 1083–1097 (2008).
   PubMed Web of Science ®Google Scholar
• Falconi M, Plockinger U, Kwekkeboom DJ et al. Well-differentiated pancreatic nonfunctioning tumors/carcinoma. Neuroendocrinology84(3), 196–211 (2006).
   PubMed Web of Science ®Google Scholar
• Ricke J, Klose KJ, Mignon M, Öberg K, Wiedenmann B. Standardisation of imaging in neuroendocrine tumours: results of a European delphi process. Eur. J. Radiol.37(1), 8–17 (2001).
   PubMedGoogle Scholar
• Gabriel M, Decristoforo C, Kendler D et al. 68Ga-DOTA-Tyr3-octreotide PET in neuroendocrine tumors: comparison with somatostatin receptor scintigraphy and CT. J. Nucl. Med.48(4), 508–518 (2007).
   PubMed Web of Science ®Google Scholar
• Sundin A, Garske U, Orlefors H. Nuclear imaging of neuroendocrine tumours. Best Pract. Res. Clin. Endocrinol. Metab.21(1), 69–85 (2007).
   PubMed Web of Science ®Google Scholar
• Oberndorfer S. Karzenoide Tumoren des Dünndarms. Frankf. Zschr. Path.1, 426–430 (1907).
   Google Scholar
• Williams ED, Sandler M. The classification of carcinoid tumours. Lancet1, 238–239 (1963).
   PubMed Web of Science ®Google Scholar
• Kloppel G, Perren A, Heitz PU. The gastroenteropancreatic neuroendocrine cell system and its tumors: the WHO classification. Ann. NY Acad. Sci.1014, 13–27 (2004).
   PubMed Web of Science ®Google Scholar
• Rindi G, Kloppel G, Alhman H et al. TNM staging of foregut (neuro)endocrine tumors: a consensus proposal including a grading system. Virchows Arch.449(4), 395–401 (2006).
   PubMed Web of Science ®Google Scholar
• Rindi G, Kloppel G, Couvelard A et al. TNM staging of midgut and hindgut (neuro) endocrine tumors: a consensus proposal including a grading system. Virchows Arch.451(4), 757–762 (2007).
   PubMed Web of Science ®Google Scholar
• Kaltsas GA, Besser GM, Grossman AB. The diagnosis and medical management of advanced neuroendocrine tumors. Endocr. Rev.25(3), 458–511 (2004).
   PubMed Web of Science ®Google Scholar
• Rubin J, Ajani J, Schirmer W et al. Octreotide acetate long-acting formulation versus open-label subcutaneous octreotide acetate in malignant carcinoid syndrome. J. Clin. Oncol.17(2), 600–606 (1999).
   PubMed Web of Science ®Google Scholar
• Beaumont J, Zhimei L, Choi S. et al. Health-related quality of life of patients with neuroendocrine tumor compared to the United States general population. Presented at: 2nd Annual Meeting of the North American NeuroEndocrine Tumor Society. Charlotte, North Carolina, USA, 2–3 October 2009.
   Google Scholar
• Basson MD, Ahlman H, Wangberg B, Modlin IM. Biology and management of the midgut carcinoid. Am. J. Surg.165(2), 288–297 (1993).
   PubMedGoogle Scholar
• Modlin IM, Öberg K, Chung DC et al. Gastroenteropancreatic neuroendocrine tumours. Lancet Oncol. 9(1), 61–72 (2008).
   PubMed Web of Science ®Google Scholar
• Kulke MH, Mayer RJ. Carcinoid tumors. N. Engl. J. Med.340(11), 858–868 (1999).
   PubMed Web of Science ®Google Scholar
• Plockinger U, Rindi G, Arnold R et al. Guidelines for the diagnosis and treatment of neuroendocrine gastrointestinal tumours. A consensus statement on behalf of the European Neuroendocrine Tumour Society (ENETS). Neuroendocrinology80(6), 394–424 (2004).
   PubMed Web of Science ®Google Scholar
• Öberg K, Jelic S. Neuroendocrine gastroenteropancreatic tumors: ESMO clinical recommendations for diagnosis, treatment and follow-up. Ann. Oncol.19(Suppl. 2), ii104–ii105 (2008).
   PubMedGoogle Scholar
• Modlin IM, Latich I, Kidd M, Zikusoka M, Eick G. Therapeutic options for gastrointestinal carcinoids. Clin. Gastroenterol. Hepatol.4(5), 526–547 (2006).
   PubMed Web of Science ®Google Scholar
• McEntee GP, Nagorney DM, Kvols LK, Moertel CG, Grant CS. Cytoreductive hepatic surgery for neuroendocrine tumors. Surgery108(6), 1091–1096 (1990).
   PubMed Web of Science ®Google Scholar
• Moller LN, Stidsen CE, Hartmann B, Holst JJ. Somatostatin receptors. Biochim. Biophys. Acta1616(1), 1–84 (2003).
   PubMed Web of Science ®Google Scholar
• Susini C, Buscail L. Rationale for the use of somatostatin analogs as antitumor agents. Ann. Oncol.17(12), 1733–1742 (2006).
   PubMed Web of Science ®Google Scholar
• Schmid HA, Schoeffter P. Functional activity of the multiligand analog SOM230 at human recombinant somatostatin receptor subtypes supports its usefulness in neuroendocrine tumors. Neuroendocrinology80(Suppl. 1), 47–50 (2004).
   PubMedGoogle Scholar
• Schmid HA. Pasireotide (SOM230), development, mechanism of action and potential applications. Mol. Cell. Endocrinol.286(1–2), 69–74 (2008).
   PubMed Web of Science ®Google Scholar
• Kvols LK, Moertel CG, O’Connell MJ, Schutt AJ, Rubin J, Hahn RG. Treatment of the malignant carcinoid syndrome. Evaluation of a long-acting somatostatin analogue. N. Engl. J. Med.315(11), 663–666 (1986).
   PubMed Web of Science ®Google Scholar
• Kvols LK, Martin JK, Marsh HM, Moertel CG. Rapid reversal of carcinoid crisis with a somatostatin analogue. N. Engl. J. Med.313(19), 1229–1230 (1985).
   PubMed Web of Science ®Google Scholar
• Garland J, Buscombe JR, Bouvier C et al. Sandostatin LAR (long-acting octreotide acetate) for malignant carcinoid syndrome: a 3-year experience. Aliment. Pharmacol. Ther.17(3), 437–444 (2003).
   PubMed Web of Science ®Google Scholar
• Welin SV, Janson ET, Sundin A et al. High-dose treatment with a long-acting somatostatin analogue in patients with advanced midgut carcinoid tumours. Eur. J. Endocrinol.151(1), 107–112 (2004).
   PubMed Web of Science ®Google Scholar
• Battershill PE, Clissold SP. Octreotide. A review of its pharmacodynamic and pharmacokinetic properties, and therapeutic potential in conditions associated with excessive peptide secretion. Drugs38(5), 658–702 (1989).
   PubMed Web of Science ®Google Scholar
• Maton PN, O’Dorisio TM, Howe BA et al. Effect of a long-acting somatostatin analogue (SMS 201–995) in a patient with pancreatic cholera. N. Engl. J. Med.312(1), 17–21 (1985).
   PubMed Web of Science ®Google Scholar
• Gyr KE, Meier R. Pharmacodynamic effects of Sandostatin in the gastrointestinal tract. Digestion54(Suppl. 1), 14–19 (1993).
   PubMedGoogle Scholar
• Dueno MI, Bai JC, Santangelo WC, Krejs GJ. Effect of somatostatin analog on water and electrolyte transport and transit time in human small bowel. Dig. Dis. Sci.32(10), 1092–1096 (1987).
   PubMed Web of Science ®Google Scholar
• Anthony LB, Martin W, Delbeke D, Sandler M. Somatostatin receptor imaging: predictive and prognostic considerations. Digestion57(Suppl. 1), 50–53 (1996).
   PubMed Web of Science ®Google Scholar
• Ruszniewski P, Ish-Shalom S, Wymenga M et al. Rapid and sustained relief from the symptoms of carcinoid syndrome: results from an open 6-month study of the 28-day prolonged-release formulation of lanreotide. Neuroendocrinology80(4), 244–251 (2004).
   PubMed Web of Science ®Google Scholar
• Modlin IM, Pavel M, Kidd M, Gustafsson BI. Review article: somatostatin analogues in the treatment of gastroenteropancreatic neuroendocrine (carcinoid) tumours. Aliment. Pharmacol. Ther.31(2), 169–188 (2010).
   PubMed Web of Science ®Google Scholar
• Ricci S, Antonuzzo A, Galli L et al. Long-acting depot lanreotide in the treatment of patients with advanced neuroendocrine tumors. Am. J. Clin. Oncol.23(4), 412–415 (2000).
   PubMed Web of Science ®Google Scholar
• Wynick D, Anderson JV, Williams SJ, Bloom SR. Resistance of metastatic pancreatic endocrine tumours after long-term treatment with the somatostatin analogue octreotide (SMS 201–995). Clin. Endocrinol.30(4), 385–388 (1989).
   PubMedGoogle Scholar
• Wynick D, Bloom SR. Clinical review 23: The use of the long-acting somatostatin analog octreotide in the treatment of gut neuroendocrine tumors. J. Clin. Endocrinol. Metab.73(1), 1–3 (1991).
   PubMedGoogle Scholar
• Hofland LJ, van der Hoek J, Feelders R, van der Lely AJ, de Herder W, Lamberts SW. Pre-clinical and clinical experiences with novel somatostatin ligands: advantages, disadvantages and new prospects. J. Endocrinol. Invest.28(11 Suppl. International), 36–42 (2005).
   PubMedGoogle Scholar
• van Vugt HH, Smid HA, Sailer AW. Ligand-dependent internalization of somatostatin receptors. Endocrine Abstracts16, P659 (2008).
   Google Scholar
• Kvols L, Wiedenmann B, Öberg K et al. Safety and efficacy of pasireotide (SOM230) in patients with metastatic carcinoid tumors refractory or resistant to octreotide LAR: results of a Phase II study. Presented at: ASCO GI Cancers Symposium. San Francisco, CA, USA, 26–28 January 2006 (Abstract 171).
   Google Scholar
• Grozinsky-Glasberg S, Shimon I, Korbonits M, Grossman AB. Somatostatin analogues in the control of neuroendocrine tumours: efficacy and mechanisms. Endocr. Relat. Cancer15(3), 701–720 (2008).
   PubMed Web of Science ®Google Scholar
• Arnold R, Trautmann ME, Creutzfeldt W et al. Somatostatin analogue octreotide and inhibition of tumour growth in metastatic endocrine gastroenteropancreatic tumours. Gut38(3), 430–438 (1996).
   PubMed Web of Science ®Google Scholar
• Panzuto F, Di Fonzo M, Iannicelli E et al. Long-term clinical outcome of somatostatin analogues for treatment of progressive, metastatic, well-differentiated entero-pancreatic endocrine carcinoma. Ann. Oncol.17(3), 461–466 (2006).
   PubMed Web of Science ®Google Scholar
• Shojamanesh H, Gibril F, Louie A et al. Prospective study of the antitumor efficacy of long-term octreotide treatment in patients with progressive metastatic gastrinoma. Cancer94(2), 331–343 (2002).
   PubMed Web of Science ®Google Scholar
• di Bartolomeo M, Bajetta E, Buzzoni R et al. Clinical efficacy of octreotide in the treatment of metastatic neuroendocrine tumors. A study by the Italian Trials in Medical Oncology Group. Cancer77(2), 402–408 (1996).
   PubMed Web of Science ®Google Scholar
• Saltz L, Trochanowski B, Buckley M et al. Octreotide as an antineoplastic agent in the treatment of functional and nonfunctional neuroendocrine tumors. Cancer72(1), 244–248 (1993).
   PubMed Web of Science ®Google Scholar
• Rinke A, Muller HH, Schade-Brittinger C et al. 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. J. Clin. Oncol.27(28), 4656–4663 (2009).
   PubMed Web of Science ®Google Scholar
• Aparicio T, Ducreux M, Baudin E et al. Antitumour activity of somatostatin analogues in progressive metastatic neuroendocrine tumours. Eur. J. Cancer.37(8), 1014–1019 (2001).
   PubMed Web of Science ®Google Scholar
• Kulke MH. Neuroendocrine tumors: is there a standard treatment? Gastrointest. Cancer Res.2(3), 152–153 (2008).
   PubMedGoogle Scholar
• Pavel M, Heuck F, Plockinger U et al. Prospective randomized trial: biotherapy versus chemotherapy in malignant nonfunctional neuroendocrine tumors of the pancreas and bronchial tract (ENET-1). Presented at: ASCO GI Cancers Symposium. Orlando, FL, USA, 25–27 January 2008 (Abstract 202).
   Google Scholar
• Faiss S, Pape UF, Bohmig M et al. Prospective, randomized, multicenter trial on the antiproliferative effect of lanreotide, interferon a, and their combination for therapy of metastatic neuroendocrine gastroenteropancreatic tumors – the International Lanreotide and Interferon Alfa Study Group. J. Clin. Oncol.21(14), 2689–2696 (2003).
   PubMed Web of Science ®Google Scholar
• Strosberg J, Kvols L. Antiproliferative effect of somatostatin analogs in gastroenteropancreatic neuroendocrine tumors. World J. Gastroenterol.16(24), 2963–2970 (2010).
   PubMed Web of Science ®Google Scholar
• Öberg K, Kvols L, Caplin M et al. Consensus report on the use of somatostatin analogs for the management of neuroendocrine tumors of the gastroenteropancreatic system. Ann. Oncol.15(6), 966–973 (2004).
   PubMed Web of Science ®Google Scholar
• Arnold R, Rinke A, Klose KJ et al. Octreotide versus octreotide plus interferon-a in endocrine gastroenteropancreatic tumors: a randomized trial. Clin. Gastroenterol. Hepatol.3(8), 761–771 (2005).
   PubMed Web of Science ®Google Scholar
• Kolby L, Persson G, Franzen S, Ahren B. Randomized clinical trial of the effect of interferon alpha on survival in patients with disseminated midgut carcinoid tumours. Br. J. Surg.90(6), 687–693 (2003).
   PubMed Web of Science ®Google Scholar
• Bondanelli M, Ambrosio MR, Zatelli MC, Cavazzini L, Al Jandali Rifa’y L, Degli Uberti EC. Regression of liver metastases of occult carcinoid tumor with slow release lanreotide therapy. World J. Gastroenterol.11(13), 2041–2044 (2005).
   PubMedGoogle Scholar
• Jensen RT, Berna MJ, Bingham DB, Norton JA. Inherited pancreatic endocrine tumor syndromes: advances in molecular pathogenesis, diagnosis, management, and controversies. Cancer113(7 Suppl.), 1807–1843 (2008).
   PubMed Web of Science ®Google Scholar
• Boulay A, Zumstein-Mecker S, Stephan C et al. Antitumor efficacy of intermittent treatment schedules with the rapamycin derivative RAD001 correlates with prolonged inactivation of ribosomal protein S6 kinase 1 in peripheral blood mononuclear cells. Cancer Res.64(1), 252–261 (2004).
   PubMed Web of Science ®Google Scholar
• Horsch D, Tielke S, Schrader J. Expression and activation of mTOR in neuroendocrine tumors: effects of mTOR inhibition by RAD001 upon growth, call cycle regulation and signaling in neuroendocrine cell lines. J. Clin. Oncol.25(Suppl. 18), 10570 (2007).
   Google Scholar
• Cejka D, Preusser M, Fuereder T et al. mTOR inhibition sensitizes gastric cancer to alkylating chemotherapy in vivo. Anticancer Res.28(6A), 3801–3808 (2008).
   PubMedGoogle Scholar
• Chollet P, Abrial C, Tacca O et al. Mammalian target of rapamycin inhibitors in combination with letrozole in breast cancer. Clin. Breast Cancer7(4), 336–338 (2006).
   PubMed Web of Science ®Google Scholar
• Yao JC, Phan AT, Chang DZ et al. Efficacy of RAD001 (everolimus) and octreotide LAR in advanced low- to intermediate-grade neuroendocrine tumors: results of a Phase II study. J. Clin. Oncol.26(26), 4311–4318 (2008).
   PubMed Web of Science ®Google Scholar
• Meric-Bernstam F, Gonzalez-Angulo AM. Targeting the mTOR signaling network for cancer therapy. J. Clin. Oncol.27(13), 2278–2287 (2009).
   PubMed Web of Science ®Google Scholar
• Pavel M. RADIANT-2 – No. LBA8. A randomized, double-blind, placebo controlled, multicentre Phase 3 trial of everolimus plus octreotide LAR vs. placebo plus octreotide LAR in patients with advanced neuroendocrine tumors (NET) (RADIANT-2). Presented at: European Society for Medical Oncology. Milan, Italy, 8–12 October 2010.
   Google Scholar
• Raymond E, Niccoli P, Raoul J et al. Cox proportional hazard analysis of sunitinib (SU) efficacy across subgroups of patients (pts) with progressive pancreatic neuroendocrine tumors (NET). Presented at: ASCO Annual Meeting. Chicago, IL, USA, 4–8 June 2010 (Abstract 4031).
   Google Scholar
• Yao J. RADIANT-3 – No. LBA9. A randomized, double-blind, placebo controlled, multicentre phase 3 trial of everolimus in patients with advanced pancreatic NETs. Presented at: European Society for Medical Oncology. Milan, Italy, 8–12 October 2010.
   Google Scholar
• Moertel CG. Treatment of the carcinoid tumor and the malignant carcinoid syndrome. J. Clin. Oncol.1(11), 727–740 (1983).
   PubMed Web of Science ®Google Scholar
• Janson ET, Ronnblom L, Ahlstrom H et al. Treatment with alpha-interferon versus alpha-interferon in combination with streptozocin and doxorubicin in patients with malignant carcinoid tumors: a randomized trial. Ann. Oncol.3(8), 635–638 (1992).
   PubMed Web of Science ®Google Scholar
• Biesma B, Willemse PH, Mulder NH et al. Recombinant interferon alpha-2b in patients with metastatic apudomas: effect on tumours and tumour markers. Br. J. Cancer66(5), 850–855 (1992).
   PubMed Web of Science ®Google Scholar
• Turner HE, Lindsell DR, Vadivale A, Thillainayagam AV, Wass JA. Differing effects on gall-bladder motility of lanreotide SR and octreotide LAR for treatment of acromegaly. Eur. J. Endocrinol.141(6), 590–594 (1999).
   PubMedGoogle Scholar
• Ekeblad S, Sundin A, Janson ET et al. Temozolomide as monotherapy is effective in treatment of advanced malignant neuroendocrine tumors. Clin. Cancer Res.13(10), 2986–2991 (2007).
   PubMed Web of Science ®Google Scholar
• Kulke MH, Stuart K, Enzinger PC et al. Phase II study of temozolomide and thalidomide in patients with metastatic neuroendocrine tumors. J. Clin. Oncol.24(3), 401–406 (2006).
   PubMed Web of Science ®Google Scholar
• Strosberg JR, Fine RL, Choi J et al. First-line chemotherapy with capecitabine and temozolomide in patients with metastatic pancreatic endocrine carcinomas. Cancer DOI: 10.1002/cncr.25425 (2010) (Epub ahead of print).
   Google Scholar
• Forrer F, Valkema R, Kwekkeboom DJ, de Jong M, Krenning EP. Neuroendocrine tumors. Peptide receptor radionuclide therapy. Best Pract. Res. Clin. Endocrinol. Metab.21(1), 111–129 (2007).
   PubMed Web of Science ®Google Scholar
• Comaru-Schally AM, Schally AV. A clinical overview of carcinoid tumors: perspectives for improvement in treatment using peptide analogs (review). Int. J. Cancer26(2), 301–309 (2005).
   Google Scholar
• Valkema R, Pauwels S, Kvols LK et al. Survival and response after peptide receptor radionuclide therapy with [90Y-DOTA0,Tyr3]octreotide in patients with advanced gastroenteropancreatic neuroendocrine tumors. Semin. Nucl. Med. 36(2), 147–156 (2006).
   Google Scholar
• Kwekkeboom DJ, de Herder WW, Kam BL et al. Treatment with the radiolabeled somatostatin analog [177 Lu-DOTA 0,Tyr3]octreotate: toxicity, efficacy, and survival. J. Clin. Oncol.26(13), 2124–2130 (2008).
   PubMed Web of Science ®Google Scholar
• Wolin E, Kvols L, Ezzat S et al. Pasireotide LAR in patients with metastatic carcinoid tumors: pharmacokinetics (PK) and safety results from a randomized, multicenter, Phase I study. Presented at: ASCO GI Cancers Symposium. San Francisco, CA, USA, 15–17 Januray 2009 (Abstract 93).
   Google Scholar
• Pasquali D, Rossi V, Conzo G et al. Effects of somatostatin analog SOM230 on cell proliferation, apoptosis, and catecholamine levels in cultured pheochromocytoma cells. J. Mol. Endocrinol.40(6), 263–271 (2008).
   PubMed Web of Science ®Google Scholar
• Pavel M, Hassler G, Schmid HA, van Vugt HH, Hahn EG, Schuppan DS. Pasireotide strongly inhibits migration and proliferation of human micro- and macrovascular endothelial cells mainly via somatostatin receptor subtype 5 and FAK, ERK1/2 and p38 pathways. ENDO Abstract 1, P2–352 (2006).
   Google Scholar
• Strosberg JR, Nasir A, Hodul P, Kvols L. Biology and treatment of metastatic gastrointestinal neuroendocrine tumors. Gastrointest. Cancer Res.2(3), 113–125 (2008).
   PubMedGoogle Scholar