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
List the symptoms of bowel cancer
- Can be asymptomatic with incidental anaemia
- Change in bowel habit (diarrhoea/constipation)
- Blood in stool
- Acute intestinal obstruction
List bowel symptoms not associated with colorectal cancer
- Rectal bleeding with anal symptoms (itch, soreness/ discomfort, lump, prolapse)
- Change in bowel habit to harder or less frequent stool
- Abdominal pain in the absence of obstruction
How could you investigate a patient with suspected colorectal cancer?
- Abdominal x-ray
- CT scan
- Barium enema
- Colonoscopy
- CT virtual colonoscopy
List the advantages and disadvantages of abdominal x ray in assessing colorectal cancer
- Cheap
- Easy
- Quick
- 77% sensitivity
- 50% specificity
List the pros and cons of a plain CT in assessing colorectal cancer
- Quick
- Easy
- Can see large lesions
- May miss smaller lesions
- No tissue
List the pros and cons of a barium enema
- Good sensitivity and specificity
- Time intesive
- Technically demanding
- Unacceptable to patients
List the pros and cons of colonoscopy
- Safe
- Relatively quick
- High sensitivity
- Can obtain tissue
- Requires 2 days of diarrhoea, with risk of dehydration
- Small risk of perforation (<1:2000)
Describe the process of CT virtual colonoscopy
- Modified bowel prep (reduced)
- Stools are tagged using bismuth
- Computer aided subtraction is used to create images
List the pros and cons of CT virtual colonoscopy
- Quick
- Easy
- Reduced bowel prep
- As good as colonoscopy for lesions >6mm
- Unable to obtain tissue or remove lesions
List the three factors commonly seen in pancreatic cancer
- Non specific symptoms
- Pain (70%)
- Anorexia (10%)
- Weight loss (10%)
List the early symptoms of pancreatic cancer
- Abdominal pain
- Depression
- Glucose intolerance
List the late symptoms of pancreatic cancer
- Weight loss
- Jaundice
- Ascites
- Obstructed gall bladder
List the outcomes for pancreatic cancer patients
- 20% suitable for resection
- Surgery curative in 20-25% of cases
- 1 year survival 18%
- 5 year survival 2%
List the risk factors for pancreatic cancer
- Smoking
- Drinking
- Obesity
- Rare conditions such as MEN