Alimentary System 14 - GI cancer Flashcards
Where does bowel cancer place in causes of cancer death?
2nd most prevalent
Where does bowel cancer place in the most common cancers?
4th most common after prostate cancer
Which cancers can occur in epithelial cells?
- Squamous epithelia form squamous cell carcinomas
- Glandular epithelium form adenocarcinomas
List the cancers that can occur in neuroendocrine cells
- Enterochromaffin cells form carcinoid tumous
- Interstitial cells of cajal form gastrointestinal stromal tumours
List the cancers that can occur in connective tissue
- Smooth muscle leiomyoma/ leiomyosarcomas
- Adipose tissue forms lipomas
What do you need to ask when a patient comes to you with difficulty swallowing (dysphagia)?
- How long
- What foods cant you swallow
- Any vomiting
- Any other symptoms
- Look at risk factors
What two cancers can form in the oesophagus?
- Adenocarcinomas
- Squamous cell carcinomas
Where do adenocarcinomas form in the oesophagus and why?
- Formed from metaplastic columnar epithelium
- Affect the lower 1/3 of the oesophagus, related to acid reflux
- More developed world
Where do squamous cell carcinomas from in the oesophagus and why?
- In the upper 2/3 of the oesophagus
- From normal oesophageal squamous epithelium
- Acetaldehyde pathway (related to alcohol)
- Less developed world
What would you do if you expected a patient had oesophageal cancer?
Endoscopy, where what looks like a river of shiny red oesophagus would be seen due to the acid and barretts oesophagus (columnar cells)
Describe the progression from reflux to cancer
- Inflammation in the oesophagus (oesophagitis)
- Barretts metaplasia
- Dysplasia
- Carcinoma
List the risk factors for bowel cancer
- Family history
- Inherited conditions (FAP, HNPCC, lynch syndrome)
- Uncontrolled ulcerative colitis
- Age
- Previous polyps
What form of cancer is seen in the bowel?
Adenocarcinoma
Describe the pathology of bowel cancer
- Not a single gene process
- Sequence of genetic errors (APC, K-ras, p53, 18q)
- APC+COX2 result in hyperproliferative endothelium and small adenoma formation
- K-ras results in large adenoma
- p53 and loss of 18q result in colon carcinoma
- Inheritence is not simple mendelian
List the causes of bowel cancer
- Aspirin
- Folate
- Calcium
- Oestrogen