Cancer of gut

Question 1

What are the three most common cancer sites in the GI tract?

Answer 1

• oesophageal
• colon
• pancreatic

Question 2

What is epithelial cell - squamous and glandular cancer called?

Answer 2

squamous - squamous cell carcinoma

glandular - adenocarcinoma

Question 3

What are nueroendocrine - enterochromaffin and interstitial cells of cajal cancers called?

Answer 3

enterochromaffin - carcinoid tumour

intersitial cells - GI stromal tumour

Question 4

What is connective tissue - smooth muscle and adipose tissue cancers called?

Answer 4

smooth muscle - leiomyoma/meiomyosarcoma

adipose - lipoma

Question 5

What are the three regions the oesophagus can be divided into?

Answer 5

cervical
middle
lower

Question 6

What are the two main types of oesophageal cancer?

Answer 6

squamous cells

adenocarcinoma

Question 7

Where does SCC occur, what pathway is used and which parts of the world is it common in?

Answer 7

• Upper 2/3 of oesophagus
• Acetaldehyde pathway
• Forms from normal oesophageal squamous epithelium
• More common in less developed world

Question 8

Where does AC occur, what pathway is used and which parts of the world is it common in?

Answer 8

• Lower 1/3 of oesophagus
• Forms from metaplastic columnar epithelium
• Related to acid reflux
• More common in more developed world

Question 9

How can acid reflux progress to carcinoma?

Answer 9

oseophagitis (inflammation) -> baretts (metaplasia) -> dysplasia -> carcinoma (neoplasm)

Question 10

How can oesophageal cancer be identified?

Answer 10

endoscopy, OGD (oesophagogastroduodenoscopy) or gastroscopy.

Question 11

What happens in Barrett’s oesophagus?

Answer 11

metaplasia from repeated exposure to stomach acid.

replacement of squamous cell mucosa -> columnar mucosa

Question 12

What is the risk of cancer from Barrett’s oesophagus?

Answer 12

• Overall risk of adenocarcinoma in Barrett’s oesophagus = 0.12%/yr.
• Post-low grade dysplasia risk of adenocarcinoma = 0.5%/yr.
• Post-high grade dysplasia risk of adenocarcinoma = 5-30%/yr.

Question 13

How often is surveillance carried out in people with Barrett’s oesophagus?

Answer 13

4 biopsies every 1cm along segment
Aspirin would reduce COX2 expression

• Barrett’s Oesophagus with no dysplasia:
  Every 3-5 years
• Barrett’s Oesophagus with low-grade dysplasia:

Every 6 months until no dysplasia.

Barrett’s Oesophagus with high-grade dysplasia:

• Flat –> Radio Frequency Ablation
• Nodular –> endoscopic mucosal resection, then HALO.

Question 14

What are the risk factors for colorectal cancer?

Answer 14

• Age (Biggest risk factor (over 50))
• Family history or specific inherited conditions (e.g. FAP, HNPCC, Lynch Syndrome).
• Uncontrolled ulcerative colitis.
• Previous polyps.

Question 15

How does colorectal cancer progress?

Answer 15

Normal (+ mutation) -> hyper proliferative epithelium -> small adenoma (+ mutation) -> large adenoma (+ mutation) -> colon adenoma (+ small cancerous invasion)

This is not a single gene process, this is a sequence of genetic errors:
APC -> K-ras -> p53 -> 18q loss

Question 16

What are the symptoms of colorectal cancer?

Answer 16

• Normally totally asymptomatic (with unknown iron-deficient anaemia = 5-10% chance of cancer)
• Change in bowel habit - e.g. diarrhoea or constipation.
• Blood in stool:
• Acute intestinal obstruction

Question 17

How is colorectal cancer investigated primarily?

Answer 17

colonoscopy

Question 18

How is colorectal cancer investigated and their advantages and disadvantages?

Answer 18

Abdominal x-ray:

• Advantages: cheap, easy, quick
• Disadvantage: Not very sensitive and specific

CT scan:

• Advantages: quick, easy, see large lesions
• Disadvantages: could miss small lesions, cannot take samples and cannot carry out treatment

Barium enema:

• Advantages: quite sensitive and specific
• Disadvantages: time insensitive, technically demanding, unacceptable for patients, very messy and they have to poo out a double cream like substance after

Colonoscopy:

• Advantages: safe, quick, high sensitivity, able to obtain tissue
• Disadvantages: 2 prep days of iatrogenic diarrhoea, small risk of perforation, small risk of dehydration

Virtual colonoscopy:

• Advantages: Quick, easy, reduced bowel prep so more tolerable, good for lesions greater than 6mm
• Disadvantages: unable to obtain tissue, unable to remove lesions

Question 19

Symptoms of early and late pancreatic cancer

Answer 19

EARLY – abdominal pain, depression, glucose intolerance

LATE – weight loss, jaundice, ascites and obstructed gall bladder.

Question 20

What is the prognosis of pancreatic cancer?

Answer 20

Prognosis is very poor

Only 20% resectable (lose all endo- and exocrine function) and surgery only curative 20-25% of cases

1-year survival rate 18%, 5-year survival rate 2%.

Question 21

Risk factors of pancreatic cancer?

Answer 21

• Smoking
• Drinking
• Obesity
• Family history

Question 22

Describe the epidemiology of colon cancer

Answer 22

• More than 30,000 new cases per year
• 1 case per GP per year
• 14% of cancer in men, 12% in women
• 1 in 25 lifetime risk
• 1 in 50 risk of dying from CRC

Question 23

Symptoms of oesophageal cancer

Answer 23

• Symptoms do not usually appear until >50% of the circumference of the oesophagus is cancerous.
• Difficulty and pain when swallowing
• Weight loss due to lack of nutrition
• Pain in the breast bone and stomach, or a feeling of reflux

In later stages, further symptoms include:

• Nausea
• Vomiting
• Regurgitation of food
• Vomiting blood