Neuroendocrine tumours

Question 1

What are neuroendocrine cells?

Answer 1

• Cells that receives input from neurotransmitters to release hormones into blood
• Allows for integration of nervous and endocrine system

Question 2

What are gastroenteropancreatic neuroendocrine tumours? (GEP-NETS)

Answer 2

• Neuroendocrine tumour originating from neuroendocrine cells in GI tract or pancreas
• All of which have maligannt potential

Question 3

What is neoplasia referred to as when arising from neuroendocrine cells in GI tract?

Answer 3

Carcinoid tumours
But can occur in pancreas and lung

Question 4

RF for NET

Answer 4

• Complex familial endocrine cancer syndromes eg MEN1, MEN2, neurofibromatosis type 1, Von Hippel Lindau
• Or can just be sporadic
• Females and family history are other RF

Question 5

Two types of GEP NETS

Answer 5

• Non functioning tumours - majority, no hormone related clinical features
• Functioning tumours - symptoms due to peptide and hormone release

Question 6

Symptoms of GEP NETS

Answer 6

• Non specific - vague abdominal pain, N+V, abdominal distenstion
• Less commonly bowel obstruction
• May also have features of underlying inherited disorder eg MEN-1

Question 7

Symptoms from functional GEPNETS

Answer 7

• Peptide hormone release - range of hormones
• 20% can present with Carcinoid syndrome

Question 8

What is carcinoid syndrome?

Answer 8

• Occurs following metastasis of carcinoid tumour
• Metastasised cells begin to oversecrete bioactive mediators eg serotonin, prostaglandins and gastrin into circulation
• Present with flushing, palps, intermittent abdominal pain, diarrhoea

Question 9

Laboratory tests for ?GEP-NETS

Answer 9

• Chromogranin A (CgA) - found in high concs regardless of functioning/non-functioning, if normal can test CgB
• Pancreatic polypeptide (PP) - if CgA and CgB normal
• Sometimes urinary 5-hydroxyindoleacetic acid (5HIAA) - breakdown of serotonin
• Genetic testing if think necessary

Question 10

Imaging for ?GEP-NETS

Answer 10

• CT imaging - unless lymphadenopathy or liver mets sensitivity is poor
• CT enteroclysis - combines cross sectional display of solid organs with luminal and mural display of small bowel
• Endoscopy - for biopsy

Question 11

What imaging is done if patients present with metastatic disease without known primary?

Answer 11

• Whole body somatostatin receptor scintigraphy

Question 12

Management of GEP-NETS

Answer 12

• Surgery is only curative option
• If well differentiated - localised disease resected, liver mets resected
• If poor - localised disease resected, then chemotherapy, if mets then palliative chemo alone

Question 13

How is carcinoid syndrome treated?

Answer 13

• Somatostatin analogues - octreotide

Question 14

What is carcinoid crisis?

Answer 14

• When major surgery or embolisation planned for patients with carcinoid syndrome prophylactic somatostain analogues should be considered to prevent this
• Intra op or post op
• Caused by overwhelming release from NET = resistant severe hypotension
• highest risk can start octreotide 24hrs prior to operation and continued for 48hrs post op

Question 15

Surgical management for GEP-NETS on location

Answer 15

• Gastric - endoscopic resection if low grade, gastrectomy with regional lymph node clearance in higher grade
• Small intestine NETs - always malignancy usually, resect wuth mesenteric LN clearance
• Appendiceal - appendicectomy, right hemicolectomy in some cases
• Colonic nets - segmental colectomy with regional LN clearance