Neuroendocrine Tumors

• what are neuroendocrine tumors?

  Neuroendocrine tumors (NETs) are tumors that form from specialized cells called neuroendocrine cells, which have traits of both nerve cells and hormone-producing cells.
• what is radionuclide therapy / peptide receptor radionuclide therapy (PRRT)?

  therapy using RF which target peptide receptors to deliver localized treatment and is used for neuroendocrine tumors.
• what is the MOA of radionuclide therapy?

  When the radiopeptide is injected into a patient’s bloodstream, it binds to protein receptors called somatostatin receptors, located on NET cells, and delivers high doses of radiation to the tumor.
• what are the components of PRRT Rf?

  • Radionuclide - delivers the actual therapeutic effect
  • Chelator - is the essential link between the radionuclide and peptide (for 177Lu and 90Y is typically DOTA, for 111In is typically DTPA)
  • Somatostatin analogue (peptide)
• what Rf are used in radionuclide therapy?

  • Iodine-131 MIBG
  • Octerotide
• Iodine-131 MIBG description

  • beta emission
  • t1/2 = 8 days
  • similar to noradrenaline
• Indications for Iodine-131 MIBG in radionuclide therapy?

  • inoperable paraganglioma,
  • inoperable phaeochromocytoma,
  • inoperable carcinoid tumor,
  • stage 3 or 4 neuroblastoma,
  • metastatic or recurrent medullary thyroid cancer
• Contraindications for Iodine-131 MIBG in radionuclide therapy?

  • pregnancy,
  • breastfeeding,
  • life expectancy less than 3 months
• Iodine-131 MIBG treatment only works if the tumor absorbs a large amount of MIBG, therefore, before it is administered, the patient has to have scan that measures how MIBG is absorbed by the tumor.
• Octreotide description

  • somatostatin analogue
  • combined with indium-111, lutetium-177 or yttrium-90 for treatment
  • cause nephrotoxicity
• what is Octreotide combined with?

  • Yttrium-DOTA-TOK (90Y): Beta radiation, 64,5h half-life, 12mm effective fly
  • Lutetium-DOTA-TATE (177Lu): Beta radiation, 163,2h half-life, 2mm effective fly
• what is the procedure for Octerotide?

  uses fractionated iv administration - one dose of 2.57 GBq is given every 2 months, repeated up to 5 times.
• Indications for Octreotide?

  gastro-enteropancreatic neuroendocrine tumors

  • gastrinoma
  • insulinoma
  • pancreatic adenoma
• what Rf are used in PET for neuroendocrine tumors?

  • 18F-FDG
  • 18F-DOPA
• what Rf are used in PET experimentation for neuroendocrine tumors?

  • 68Ga-DOTA-exendin-4 – receptors GLP-1 (glucagon-like peptide) for detection of insulinoma
  • 99mTc-EDDA/HYNIC-BN – gastrin reception
• Type of radioiodine used for the treatment of neuroendocrine tumors?

  • Iodine 131-MIBG
  • 90Y/177Lu-DOTA-TOC
• With what is DOT used?

  • Gallium -DOTA-TOC (best method for PET/CT) => PARAGANGLIOMA with metastasis
  • Yttrium -DOTA-TOC => for treatment suitability assessment
  • Lutetium -DOTA-TOC => for treatment of advanced neuroendocrine tumours