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neuroendocrine%20tumors
NEUROENDOCRINE TUMORS
Treatment Guideline Chart
Neuroendocrine tumors are rare, small, slow-growing epithelial neoplasms with predominant neuroendocrine differentiation found in most organs of the body.
They arise from cells throughout the diffuse endocrine system.
Carcinoid tumors and pancreatic neuroendocrine tumors are the most common.
Carcinoid tumors arise from the lungs & bronchi, stomach, small intestine, appendix, rectum or thymus.
Majority of the neuroendocrine tumors are sporadic but some tumors are caused by inherited genetic syndromes such as multiple endocrine neoplasia, Von-Hippel Lindau disease, tuberous sclerosis complex and neurofibromatosis.
They have the ability to store and secrete various peptides and neuroamines.

Radioisotope Therapy

Peptide Receptor Radionuclide Therapy (PRRT) or Radioisotope Therapy
  • Can be considered in both functional and nonfunctional NETs with a positive SSR scintigraphy regardless of site of primary tumor
  • Radiolabeled cytotoxic agents are being investigated to target the overexpression of SSRs of the malignant pancreatic NETs
  • Lutetium 177Lu-dotatate is a radiolabeled somatostatin analog used as PRRT
    • Approved for the treatment of SSR-positive gastroenteropancreatic NETs, including foregut, midgut and hindgut
      • Option for patients with locoregionally advanced and/or metastatic NETs of the gastrointestinal tract
    • May be used in patients with distant metastases from SSR-positive NETs of bronchus, lung or thymus with disease progression on somatostatin analogs
    • May also be considered in patients with locoregionally advanced and/or metastatic neuroendocrine pancreatic tumors
  • Tumor-targeted treatment with radioactive Octreotide derivatives 111In-D-Phe(1)-Tyr(3)-octreotide (111In-DOTA-octreotide) or 90Y-DOTA-octreotide and 177Lu-DOTA-octreotate and with 131I-MIBG are associated with varied response rates and clinical benefit
    • Patients with malignant NETS treated with [177Lu-DOTA-Tyr3]octreotide found a complete response in 2% of patients, partial response in 32% of patients, and stabilization in 34% of patients
    • Radiolabeled somatostatin analogs may also be considered for advanced pancreatic NETs
Radiation Therapy
  • External radiation therapy has limited value in NETs
    • Palliative option in patients with local disease when surgery is not feasible
    • Reserved for cases of known residual disease in which complete surgical resection is not possible
    • Often results in scarring and fibrosis which may interfere with tumor evaluation and make future surgical interventions difficult and potentially dangerous
    • Causes loss of SSRs on tumor cell surfaces which decreases the effectiveness of somatostatin analogs
  • Radiotherapy is only recommended for bone and brain metastases
    • Used to treat some bone lesions from malignant pheochromocytoma or paraganglioma, especially those that are rapidly growing
    • Effective in the treatment of pain from bone metastasis
    • Prophylactic cranial irradiation is considered in patients with small-cell lung cancer with successfully treated limited-stage disease and in patients with poorly differentiated neuroendocrine carcinomas of the head neck or unknown primary site
  • Recommended for thymic carcinoid tumors after surgery
    • Radiotherapy with or without systemic therapy may be considered in intermediate grade (atypical carcinoid) thymic tumors
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