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Gastrointestinal > Lower GI tumours > Flashcards

Lower GI tumours Flashcards

1
Q

What type of tumours occur in the small intestine?

A

Malignant:

  • adenocarcinoma
  • Non-Hodgkin’s lymphoma
  • Carcinoid

Benign:

  • Peutz-Jeghers syndrome
  • Adenomas, Leiomyomas, Lipomas
  • FAP
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2
Q

What are the symptoms of small intestine tumours?

A 
Abdominal pain
Diarrhoea
Anorexia
Anaemia
Malabsorption
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3
Q

Where in the small intestine do adenocarcinomas most commonly occur?

A

In the duodenum

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4
Q

What are the risk factors of cancer of the small intestine?

A 
Crohn's disease
Coeliac disease
Family history
Poor lifestyle: smoking, alcohol, diet
Radiation exposure
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5
Q

What cells does Non-Hodgkin’s lymphoma affect in the small intestine?

A

The lymphocytes: either B or T

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6
Q

What is the treatment for NHL and adenocarcinoma?

A

Surgical resection

Chemotherapy + Radiotherapy if needed

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7
Q

What is Peutz-Jeghers syndrome?

A

A genetic condition, autosomal dominant

Consists of:

  • mucocutaneous pigmentation (hands, feet)
  • hamartomatous benign GI polyps
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8
Q

Peutz-Jeghers syndrome causes GI polyps, where in the GI system do they most occur?

A

Small intestine

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9
Q

Why do you need to be concerned about Peutz-Jeghers syndrome?

A

The polyps can bleed or cause intussusception (telescoping)

Also they can become malignant

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10
Q

What is an:

  • adenoma
  • leiomyoma
  • lipoma?
A

Adenoma: benign tumour formed of glandular structures in epithelial tissue

Leiomyoma: benign tumour formed of smooth muscle

Lipoma: benign tumour formed of fatty tissue

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11
Q

What are carcinoid tumours of the small intestine?

A

A type of neuroendocrine tumour

Malignant tumours of cells of the neuro and endocrine system

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12
Q

What cells do carcinoid s. intestine tumours arise from?

What’s the normal function of these cells?

How does the tumour affect these cells’ functions?

A

Enterochromaffin cells

They release serotonin
In the small intestine

Causes excess release of serotonin

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13
Q

Describe the function of healthy enterochromaffin cells?

A

They are found around the small intestine

When they sense food in the lumen they release serotonin which makes the gut contract around the food, pushing it down

When they detect an irritant in food they release more serotonin to make food move through even faster, this is what causes diarrhoea

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14
Q

What is carcinoid syndrome?

A

Symptoms caused by the over-secretion of serotonin caused by a carcinoid tumour

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15
Q

Carcinoid syndrome occurs in all patients with carcinoid tumours of the small intestine.
True or false?

A

False

It only occurs if they have liver metastases

In about 5% of patients

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16
Q

Why does carcinoid syndrome occur?

A

It occurs when the liver loses the ability to metabolise the excess serotonin

So the serotonin builds up and causes symptoms

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17
Q

What are the clinical features of carcinoid syndrome?

A

Flushing
Wheezing
Diarrhoea
Abdominal pain

Right heart valvular fibrosis: tricuspid, pulmonary valves
Stenosis + regurgitation

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18
Q

Investigations of carcinoid syndrome?

A

Urine sample: you will see high levels of 5-HIAA which is the breakdown product of serotonin

USS: will show liver metastases

19
Q

Management of carcinoid syndrome?

A

Somatostatin analogues: octreotide

Reducing tumour mass surgically

Chemotherapy

20
Q

What tumours occur in the colon + rectum?

A 
Adenocarcinoma
Squamous cell carcinoma
Carcinoid tumours
Sarcoma
Non-Hodgkin Lymphoma
21
Q

Which is the most common colorectal cancer?

A

Adenocarcinoma

22
Q

What are the risk factors for colon cancer?

A

Familial colon cancer disorders

Family history of colorectal cancer
IBD: Crohn's + UC
Diet: low fibre, lots of red meats
Alcohol
Smoking
23
Q

What is sarcoma?

A

Cancer of connective tissue: in the colon they are usually leiomyosarcomas: smooth muscle tumour

24
Q

What are the familial colon cancer disorders?

A

FAP: Familial Adenomatous Polyposis

HNPCC: Hereditary Non-polyposis Colorectal Cancer

25
Q

What is FAP and why does it cause colorectal cancer?

A

Familial Adenomatous Polyposis

Genetic condition in which they develop thousands of polyps in the colon at an early age

Having these polyps puts you at an increased risk of one of them becoming malignant - colon cancer

They will usually get colon cancer during their 20s

26
Q

What is the pathophysiology of FAP?

A

Adenomatous polyposis colon protein (APC) is affected

Usually APC prevents levels of the protein beta canenin getting too high by binding to it

If beta canenin levels get too high the protein moves to the nucleus, damages DNA causing adenomas

27
Q

Which protein is mutated in FAP?

A

APC

Adenomatous polyposis colon protein

28
Q

How can you treat FAP?

A

Total colectomy: removal of bowel

29
Q

What is HNPCC and why does it cause colorectal cancer?

A

Hereditary non-polyposis colorectal cancer

They are born without a copy of a gene that codes for a protein that finds and fixes DNA errors in the body

So DNA damage is not detected and fixed so it is allowed to cause adenomas

Adenomas then lead to malignancy

30
Q

Why is chemotherapy unsuccessful in HNPCC?

A

Because chemo damages DNA and relies on the body’s repair proteins to find and fix the damage

If they don’t have these proteins they can’t find the damage so it is not fixed and can lead to malignancy

31
Q

Which part of the colon are tumours most commonly found?

A

Left side

The side closest to rectum

32
Q

Clinical features of colorectal cancer?

A

Depends on site

Left:

  • bleeding and mucus
  • altered bowel habit
  • obstruction
  • tenesmus
  • colicky pain
  • thinner stools

Right side:

  • weight loss
  • iron deficiency anaemia
  • pain
33
Q

Why is obstruction more common in left colon tumours than right?

A

Right sided tumours tend to be exophytic (they grow outwards into lumen)
The bowel is stretchy so can accommodate meaning now obstruction occurs

Left-sided tumours tend to be circumferential (grow around bowel lumen) they constrict the bowel. Bowel can’t accommodate so obstruction occurs

Signs of metastatic disease

34
Q

Why do left sided colon cancers cause thin stools?

A

Because the tumours usually grow circumferentially, constricting the bowel

35
Q

Why do right sided colon cancers usually present with iron deficiency anaemia initially?

A

Anaemia is caused by blood loss

Because R sided tumours don’t cause obstruction people don’t notice them until they are advanced enough to cause anaemia

36
Q

Describe the progression of normal gut epithelia to malignant colorectal adenocarcinoma?

A

Normal epithelium
Adenoma
Colorectal adenocarcinoma

37
Q

What are adenomas (specific to colon)? Who gets them?

A

Benign growth of glandular epithelium in the colon

1/3rd of people over 60 have them
People with genetic conditions like FAP

38
Q

Do all adenomas lead to malignancy?

A

No!

But the more you have the more chance you have of one developing into an adenocarcinoma

39
Q

Investigations of colorectal cancer?

A

Bloods: FBC to look for anaemia

Faecal occult blood: look for presence of blood in stools

Barium enema to show up blockage

Endoscopy: flexible sigmoidoscopy or colonoscopy

CT/MRI to look for mets

DNA test if suspect genetic cause (FAP/HNPCC)

40
Q

Where to colorectal cancers often metastasise to?

A

Liver
Lung
Bone

41
Q

How are colorectal cancers usually classified?

A

Duke’s classification

TNM

42
Q

Explain Duke’s classification?

A

Stages A-D

A = limited to the innermost muscle layer of bowel wall, the muscularis mucosa

B = extension through the muscle layer

C = spread to at least one lymph node close to bowel

D = metastasised to other part of body

43
Q

Management of colorectal cancer?

A

Surgical resection of segment tumour is and anastomosis of remaining bowel
Sometimes colostomy is required

Post-operative adjuvant chemotherapy helps in cancers with local or lymph spread

Pre-operative radiotherapy can help shrink the tumour

Metastatic cancer: you can try to remove metastases but often its best to go for palliative care

44
Q

Which people are eligible to bowel cancer screening in the UK?

A

Men and women aged 60-74

People with family history

Gastrointestinal (20 decks)

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