Neuroendocrine tumours Flashcards
What is a neuroendocrine tumour (NET)?
A tumour that develops in the cells of the neuroendocrine system
They are usually cancerous
What is the neuroendocrine system?
A system of nerves and gland cells
The cells make hormones and release them into the blood stream
Where are neuroendocrine cells found in the body?
Most organs, particularly the
- lungs
- oesophagus
- liver
- stomach
- small + large bowel
- appendix
What do neuroendocrine cells do in the gut?
Release hormones that control release of digestive juices into the gut, and control the muscles to move food through the bowel
What do neuroendocrine cells do in the lungs?
Release hormones that control bronchoconstriction and dilation and vasoconstriction and dilation
Neuroendocrine tumours grow quickly. True or false?
False, they usually grow slowly
How do you classify neuroendocrine tumours?
If they are functioning and non-functioning
By where they are
What is a carcinoid tumour?
The old name for what is now neuroendocrine tumours
Carcinoid tumours now are defined as neuroendocrine tumours arising from the fore, mid and hindgut
List some types of neuroendocrine tumours of the pancreas?
Insulinoma: produce insulin
Gastrinoma: produce gastrin
Glucagonoma: produce glucagon
VIPoma: produce vasoactive intestinal peptide
Describe the classification of NETs by location?
They are either:
- Pancreatic endocrine tumours
OR
- Arising from foregut, midgut and hindgut (carcinoid)
Causes of NETs?
Some genetic syndromes cause NETs
We don’t know of any environmental causes
NETs (carcinoid tumours) arise from the fore, mid and hindgut. Name the most common places these tumours are seen in each of these?
Foregut: bronchus, stomach
Midgut: appendix, small bowel
Hindgut: rectum, colon
How are NETs usually discovered?
Incidentally
Or by presentation with carcinoid syndrome
What is carcinoid syndrome?
Caused by hormone secretion from the NET
Abdominal pain
Dry flushing of face (i.e. no sweating)
Diarrhoea often 10-20 times a day
NET liver metastases often have already developed before people present with carcinoid syndrome.
True or false?
True
Which is problematic
What causes death in carcinoid tumours?
Carcinoid heart disease: fibrotic heart valves
Cachexia
Liver failure (less often)
Investigation of NETs?
5HIAA in urine is raised in 24 hour urine test
Chromogranin A
Imaging to find where it is, how big, any metastasis
Endoscopic USS
What is 5HIAA and what is its relevance in NETs?
Tryptophan is broken down to make 5HIAA, it can be measured in urine
5HIAA is increased in NETs because they release chemicals that break it down?
Treatment of NETs?
Treat the symptoms and the excessive hormone state
Curative surgery by removing tumour or debulking it
Treat metastatic disease
Which hormones do NETs often produce too much of?
Somatostatin
What drugs are used to treat NETs, specifically carcinoid tumours?
Somatostatin analogue therapy
Drugs which bind to receptors and switch of somatostatin production
Octreotide, lanreotide
Name the main somatostatin analogue drugs? How are they administered?
Octreotide
Lanreotide
Injection
What drugs are used to treat pancreatic endocrine tumours?
Everolimus
Sunitinib
What are endocrine cancer syndromes?
Genetic conditions which cause high chance of developing neuroendocrine tumours
Name 3 endocrine cancer syndromes?
MEN 1
MEN 2
Von Hippel Lindau
Inheritance pattern of MEN 1 and 2?
Autosomal dominant
Describe how MEN 1 causes endocrine cancers?
Mutation of one copy of the tumour suppressor gene
So if one gets silenced or damaged in life, they will have no tumour suppression, so will develop cancers
What does MEN 1 cause in the body?
The three Ps
Pituitary tumours
Parathyroid tumours
Pancreatic tumours
When and how do patients with MEN 1 present?
The parathyroid is often affected first
Causes excess parathyroid hormone, which causes calcium to break out of the bones and into the blood stream
They often present with bone problems in their 20s
What does ‘MEN’ stand for?
Multiple endocrine neoplasia
What does MEN 2 cause in the body? There are 2 types!
Type A
- medullary thyroid cancer
- hyperparathyroidism
- Phaeochromocytoma
Type B
- all of above
- ganglioneuroma
- marfanoid habitus
At what age do patients with MEN 2 present?
MEN 2 causes cancers very early
Children with known family history of MEN 2 are screened at an early age
If they have MEN 2 they undergo a thyroidectomy as prophylaxis
What is Von Hippel Lindau?
Autosomal dominant condition of the VHL gene which causes increased development of:
- Phaeochromocytoma
- Renal cell carcinoma
- CNS haemangioma affecting retina, spinal cord, cerebellum
