16 Cancer Flashcards
Q: What is cancer? Primary cancer? Secondary? Most common cancer of GIT?
A: disease caused by an uncontrolled division of abnormal cells in a part of the body.
Primary cancers arise directly from the cells in an organ.
Secondary cancers and metastases spread from another organ, directly or by other means (blood or lymph).
colon
Q: Oesophageal cancer. Name 2. Where does an the first arise? (2) Related to? Where is it more prevalent?
Where does the second arise? (2) Pathway? Where is it more prevalent?
A: adenocarcinoma (glandular epithelium cancer)
- From metaplastic columnar epithelium
- Lower 1/3 of oesophagus
- Related to acid reflux
- More developed world
Squamous cell carcinoma
- From normal oesophageal squamous epithelium
- Upper 2/3 of oesophagus
- Acetaldehyde pathway
- Less developed world
Q: What investigations are carried for colon cancer? (5)
A: Abdominal radiograohy (X-ray) Plain computer tomography (CT) Barium Enema Colonoscopy* best CT virtual colonoscopy
Q: What are the risk factors for colon cancer? (6)
A: Family History Specific inherited conditions (Familial adenomatous polyposis, Hereditary non-polposis colon cancer) FAP, HNPCC, Lynch Syndrome Uncontrolled Ulcerative Colitis Age Previous Polyps
Q: When is pancreatic cancer often diagnosed? Outcome? (2) What is the effect of surgery? 1 year survival? 5 year?
A: diagnosis is often very late
Generally, the outcome is poor and only 20% are suitable for a resection.
Surgery is curative in 20-25% of cases; 1-year survival 18%, and 5-year survival 2%.
Q: What are the early symptoms for pancreatic cancer? (3) Subsequent advance symptoms? (4)
A: -depression
- abdominal pain
- glucose intolerance
- weight loss
- jaundice
- ascites = accumulation of protein-containing (ascitic) fluid within the abdomen
- gall bladder obstructions.
Q: Name 4 risk factors for pancreatic cancer?
A: Smoking
Drinking
Obesity
Family - Especially rare conditions such as MEN
Q: What are the cells of the GIT? (name 3 types and 2 examples for each)
A: Epithelial Cells
- Squamous
- “glandular epithelium”
Neuroendocrine Cells
- Enterochromaffin cells
- Interstitial cells of Cajal
Connective Tissue
- Smooth muscle
- Adipose tissue
Q: What type of cancer can arise from:
(Epithelial Cells)
- Squamous
- “glandular epithelium”
(Neuroendocrine Cells)
- Enterochromaffin cells
- Interstitial cells of Cajal
(Connective Tissue)
- Smooth muscle
- Adipose tissue
Main?
A: Squamous Cell Carcinoma
Adenocarcinoma**
Carcinoid tumours
Gastrointestinal Stromal Tumours
Leiomyoma/leiomyosarcomas
Lipomas
Q: What are the 5 steps in the development for adenocarcinoma? Where can it happen? (2)
A: of glandular epithelium
- Normal epithelium
- Hyperplasia - abnormal proliferation of epithelial cells (barretts)
- Development of adenomatous polyps
- Development of adenocarcinoma
- Metastasis
oes and colon
Q: What are the main causes of squamous cell carcinoma? (3) Explain one cause. Where is it more common? why?
A: Main causes are tobacco smoking and chewing, alcohol consumption, and ingestion of caustic substances.
The link to alcohol is due to the acetaldehyde metabolite, which damages the epithelial cells.
This is more common in the Asian population, where mutations in the acetaldehyde dehydrogenase enzyme leads to build up of this metabolite, increasing the risk of cancer.
Q: What is the 6 stage development of squamous cell carcinoma?
A: 1. Normal epithelium
- Metaplasia - development of abnormal squamous cell
- Dysplasia - proliferation of abnormal cells
- Severe dysplasia - almost all cells are abnormal
- Development of squamous cell carcinoma (neoplasia)
- Metastitsis
Q: When do the symptoms of oesophageal cancer arise? What are they? (4) In later stages, further symptoms include? (4)
A: Symptoms do not usually appear until a >50% of the circumference of the oesophagus is cancerous. This is due to the tumour narrowing the tube.
Difficulty and pain when swallowing
Weight loss - due to lack of nutrition
Pain in the breast bone and stomach, or a feeling of reflux
Nausea, vomiting, and regurgitation of food
Vomiting blood, due to trauma to the tumour
Q: Name 3 clinical investigations for oesophageal cancer. What do they each do?
A: Endoscopy, called an ‘oesophagogastroduodenoscopy’. Includes using a camera to observe the tumour, and a biopsy to evaluate the cells by histology
CT scan to check for metastasis
Endoscopic ultrasound - to determine level of invasion
Q: How does oesophageal anatomy change?
A: more smooth at top and more skeletal at end
Q: What is neoplasia?
A: presence or formation of new, abnormal growth of tissue
Q: What is barretts oesophagus?
A: metaplasia (replacement of one differentiated cell type with another) due to chronic inflammation
Replacement of the Squamous cell mucosa with columnar mucosa
Q: What are the main causes of colorectal cancer? (6) Current screening programme?
A: old age, and lifestyle factors including diet (link to consumption of red meat and processed meat), alcohol, obesity, tobacco smoking and lack of physical activity.
screening of the population exists in the form of a faecal sample, which tests for the presence of blood. Currently offered every 2 years for those over 60 years of age.
Q: What is oesophageal adenomacarcinoma related to? (4)
A: Related to acid reflux - repeated damage to the epithelium. Also associated with obesity, but due to unknown cause, tobacco smoking and alcohol consumption.
Q: In terms of genetics, what can cause colonic adenocarcinoma? Inheritance?
A: Not a single gene process
Sequence of genetic errors
APC, K-ras, p53, 18q
Inheritance therefore not simple Mendelian
Q: What are the symptoms for colon adenocarcinoma? (4)
A: Asymptomatic (incidental anaemia)-> esp caecum
Change in Bowel Habit
Diarrhoea (seen more)
Constipation
Blood in Stool
Acute intestinal obstruction
Q: What symptoms are not associated with colorectal cancer? (6)
A: Rectal bleeding with anal symptoms
Itch / Soreness / discomfort
External lump
prolapse
Change in bowel habit to harder or less frequent stool
Abdominal pain in the absence of obstruction
Q: What are the advantages of an abdominal X ray? (3) Down? (2)
A: Cheap
Easy
Quick
Sensitivity for obstruction 77%
Specificity for obstruction 50%
=> not v useful
A: What are the advantages of a plain CT? (3) Disadvantages? (3)
A: Quick
Easy
See large lesions
May miss smaller lesions
No tissue
No therapy
Q: What is a barium enema? Advantages? Downsides? (3)
A: barium is put in large intestine through anus -> get radiologic view with scanning
Reasonable Sensitivity and Specificity
Time Intensive
Technically demanding
Unacceptable to patients
Q: 4 advantages of a colonoscopy? Downside? (3)
A: Safe
Relatively quick
High Sensitivity
Able to obtain tissue
bowl prep:
2 days of iatrogenic diarrhoea
Small risk of perforation (<1:2000)
Risk of dehydration
Q: What is needed to a CT virtual colonoscopy? (3) Advantages? (4) Downsides? (2)
A: Modified (reduced) bowel prep
“tag” stool using Bismuth
Computer aided subtraction to create images
Quick
Easy
Reduced Bowel prep more tolerable
As good as colonoscopy for lesions >6mm
Unable to obtain tissue
Unable to remove lesions
Q: What is dysplasia?
A: expansion in immature cell types replacing more mature cells
