Cancer of the gut

Question 1

Describe what is meant by cancer

Answer 1

a disease caused by an uncontrolled division of abnormal cells in a part of the body

Question 2

Distinguish between primary and secondary (metastatic cancers)

Answer 2

Primary
Arising directly from the cells in an organ
Secondary/Metastasis
Spread from another organ, directly or by other means (blood or lymph)

Question 3

Describe cancers of the epithelial cells in the G.I tract

Answer 3

§ Squamous — Squamous cell carcinoma

§ “Glandular epithelium” — Adenocarcinoma

Question 4

Describe the cancers of the neuroendocrine cells in the G.I tract

Answer 4

§ EnteroChrommafin cells —- Carcinoid tumours

§ Interstitial cells of Cajal —- GI Stromal tumours

Question 5

Describe the cancers of connective tissue in the G.I tract

Answer 5

§ Smooth muscle — Leiomyoma/leiomyosarcomas

§ Adipose tissue – - Lipoma

Question 6

What happens as you go down the oesophagus

Answer 6

Increased smooth muscle/ reduced skeletal muscle

Question 7

List some common G.I cancers

Answer 7

Oesophageal
Stomach
Biliary system
Pancreatic
Colorectal - small intestine, large intestine, colon and anus

Question 8

Describe the situation with liver cancers

Answer 8

Few liver cancers are rarely primary- high blood flow so lots of cancers from the G.I tract can metastasize there

Question 9

Summarise oesophageal anatomy

Answer 9

Divided into thirds
Cervical oesophagus – narrow

Middle oesophagus- impressions form aorta and left main bronchus

Lower oesophagus- impressions from left atrium

Question 10

Describe squamous cell carcinoma of the oesophagus

Answer 10

From normal oesophageal squamous epithelium
Upper 2/3
Acetaldehyde pathway
Less developed world

Question 11

Describe adenocarcinoma of the oesophagus

Answer 11

From metaplastic columnar epithelium
Lower 1/3 of oesophagus
Related to acid reflux
More developed world

Question 12

What is the most common epithelium of the G.I tract

Answer 12

Glandular epithelium
Distal oesophagus, small bowel, large bowel
Adenocarcinomas therefore most common - particular in colorectal cancer

Question 13

Compare cancers of the chromaffin cells to interstitial cells of Cajal

Answer 13

chromaffin cells are more benign

Question 14

List some symptoms of oesophageal cancer

Answer 14

Long history of heart burn, regurgitation and burping
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, and regurgitation of food
Vomiting blood, due to trauma to the tumour

Question 15

Describe adenocarcinomas of the oesophagus

Answer 15

Related to acid reflux - repeated damage to the epithelium. Also associated with obesity, but due to unknown cause, tobacco smoking and alcohol consumption.
Occurs 10 times more frequently in men, possibly due to hormonal control in women, and more often in the developed world.

Question 16

Describe squamous cell carcinomas of the oesophagus

Answer 16

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.

Question 17

What is acid reflux linked to

Answer 17

Obesity- increased abdominal pressure forces the acid up

Question 18

What is regurgitations

Answer 18

Food coming back up and being swallowed again

Question 19

Outline the progression from reflux to adenocarcinoma

Answer 19

Oesophagitis (inflammation) - due to chronic exposure to acid (15% of population will have GORD)
Due to injury, ongoing inflammation and cytokine drive this can progress to Barret’s oesophagus (5-13% of GORD)
5% of these will progress to dysplasia each year
And 0.5%-30% of these will progress to carcinoma

Question 20

What is important about swallowing

Answer 20

The textures of what they can swallow

Achalasia- failure of LOS to relax

Question 21

Outline the clinical investigations for oesophageal cancer

Answer 21

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

Question 22

List the risk factors for colon cancer

Answer 22

Family History
Inflammatory bowel disease (Crohns, ulcerative colitis)
Specific inherited conditions
Familial adenomatous polyposis, Hereditary non-polposis colon cancer, Lynch Syndrome
Uncontrolled Ulcerative Colitis
Age (>50)
Previous Polyps

Question 23

Describe the progression of colon cancer

Answer 23

Normal epithelium — hyperproliferative epithelium with aberrant cryptic foci (due to APC mutation often induced by aspirin, other NSAIDS, folate and calcium)- will overexpress COX-2

This can progress to a small adenoma (again due to aspirin and other NSAIDS)

A k-ras mutation induced by estrogens and aspirin can result in the formation of a large adenoma

p53 mutation and loss of 18q can cause progression to colon carcinoma

Question 24

Summarise the pathology of colon cancer

Answer 24

Not a single gene process

Sequence of genetic errors
APC, K-ras, p53, 18q

Inheritance therefore not simple Mendelian

Question 25

List the symptoms of colorectal cancer

Answer 25

Asymptomatic (incidental anaemia)- blood loss in G.I tract can be occult- you may not notice it Change in Bowel Habit Diarrhoea Constipation Blood in Stool Acute intestinal obstruction Loss of appetite Loss of weight Nausea and Vomiting

Question 26

Which symptoms are not associated with colorectal cancer

Answer 26

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 Positive findings at colonoscopy are as frequent as for completely asymptomatic age matched control

Question 27

Outline the investigations for colorectal cancer

Answer 27

``` A: Abdominal X-Ray B: CT Scan C: Barium enema D: Colonoscopy- ate primarily with a COLONOSCOPY E: CT Virtual colonoscopy ```

Question 28

Describe blood in the stool

Answer 28

o Bright blood probably from the colorectal area so is not that bad. o Black or dark blood in stool is much more concerning as from early bowel.

Question 29

Describe the use of an abdominal X-Ray

Answer 29

Cheap Easy Quick Sensitivity for obstruction 77% Specificity for obstruction 50% So not that useful

Question 30

Describe the use of a plain CT

Answer 30

Quick Easy See large lesions May miss smaller lesions No tissue No therapy

Question 31

Describe the use of barium enema

Answer 31

Reasonable Sensitivity and Specificity Time Intensive Technically demanding Unacceptable to patients- may have to poo out a double cream like substance afterwards

Question 32

Describe the procedure for a barium enema

Answer 32

Tube up bottom- pump up barium- roll them on their side- allows you to see the colon - better sensitivity and specificity than a plain CT Can do a double contrast- pump air up bowel afterwards- to see the lining of the bowel afterwards

Question 33

Describe the use of colonoscopy

Answer 33

Safe Relatively quick High Sensitivity Able to obtain tissue 2 days of iatrogenic diarrhoea Small risk of perforation (<1:2000) Risk of dehydration Can be technically challenging- moving a rigid tube in a tube that can move- need a roadmap

Question 34

How can you identify caecum

Answer 34

Appendix Tri-radiate folds Ileo-caecal valve

Question 35

What is bowel prep

Answer 35

horrendous diahhroea- to clear bowel - if not done properly you will not get decent views

Question 36

Describe CT virtual colonoscopy

Answer 36

Drink barium- put them through CT scanner- poo labelled with bismuth- subtracted Modified (reduced) bowel prep “tag” stool using Bismuth Computer aided subtraction to create images

Question 37

Describe the use of CT virtual colonoscopy

Answer 37

Quick Easy Reduced Bowel prep more tolerable As good as colonoscopy for lesions >6mm Unable to obtain tissue Unable to remove lesions- will need colonoscopy to get tissue and then remove the polyp

Question 38

How can we remove the polyps

Answer 38

Current through base of polyp If we cut through it will bleed saline injected into wall to remove polyp from wall

Question 39

Summarise pancreatic cancer

Answer 39

“Silent Killer” Non specific symptoms Virchow’s triad Pain – 70% Anorexia – 10% Weight loss – 10%

Question 40

List the early symptoms for pancreatic cancer

Answer 40

Abdominal pain Depression Glucose intolerance

Question 41

List the late symptoms for pancreatic cancer

Answer 41

Weight loss Jaundice Ascites Obstructed gall bladder Not much you can do here

Question 42

Describe the outcomes for pancreatic cancer

Answer 42

Outcome is poor: Only 20% are suitable for a resection when they present Surgery is curative in 20-25% of cases- part of duodenum removed, pancreas removed, gall bladder removed, have to be very fit- 1 year survival 18% 5 year survival 2%

Question 43

List the risk factors for pancreatic cancer

Answer 43

``` Smoking Drinking Obesity Family Especially rare conditions such as MEN (multiple endocrine neoplasia) ```

Question 44

Describe the surveillance for oesophageal cancer

Answer 44

4 biopsies every 1cm along segment. Aspirin would reduce COX2 expression § Barrett’s Oesophagus – NO dysplasia: o Every 3-5 years. § Barrett’s Oesophagus – Low-grade dysplasia: o Every 6 months until NO dysplasia. § Barrett’s Oesophagus – High-grade dysplasia: o Flat – Radio Frequency Ablation (e.g. HALO – RFA in a 360 motion in oesophagus). o Nodular – endoscopic mucosal resection, then HALO. Can give aspirins and PPIs to reduce COX-2 expression

Question 45

Describe low grade dysplasia

Answer 45

4% of those with Barret's 1.5 % of patients with low grade dysplasia progress to high grade 0.5% progress to oesophageal adenocarcinoma

Question 46

Describe the treatment for oesophageal cancer

Answer 46

Surgery In early stages, the tumour may be removed from the oesophageal wall Oesophagectomy - removal of part of the oesophagus Chemotherapy and radiotherapy

Question 47

Describe the treatment for colorectal cancer

Answer 47

Surgery - removal of the tumour via colonoscopy or laparotomy. This may result in removal of large parts of the colon, resulting in a colostomy. Chemotherapy and radiotherapy