T1 L13: Bowel cancer - pathology and screening process Flashcards
What are the risk factors of bowel cancer?
Red meat, fat, Longstanding ulcerative colitis, crohns disease, presence of adenoma in the large bowel, FM of bowel cancer, old age
What foods reduce the risk of bowel cancer?
Veg, fruit, and fibre
What things lower the risk of bowel cancer?
Physical activity, low BMI, healthy diet
How does a high fibre diet reduce your risk of bowel cancer? (3 reasons)
- It increases the formation of short chain fatty-acids which promote health of gut microorganisms and reduces the proliferation of neoplastic cells
- It decreases the transmit time of the stool so the possible carcinogens have less interaction with the bowl mucosa
- fibre reduces the formation of secondary bile acids which can be carcinogenic
What is a polyp?
A protruding growth into a hollow viscus
What is an adenoma?
A non-cancerous tumour
What does hyperplastic mean?
A growth like a polyp that rarely turn into cancer
What is the difference in appearance between between villous and tubular adenoma?
Tubular looks like tubes, villous looks like fingers. Tubularvillous has a mixture of both
What is the adonoma-carcinoma sequence?
The progression of normal mucosa to adenoma or cancer
What is familial adenomatous polypsis?
When someone has hundreds of dysplastic polyps in their large intestine.
What is the minimum of polyps in the large intestine needed to make a diagnosis of familial adenomatous polyposis (FAP)?
100
What is the prophylactic treatment for familial adenomatous polyposis (FAP)?
Colectomy at around the age of 20
What is the genetic reason for familial adenomatous polyposis (FAP)?
A hereditary autosomal dominant condition on chromosome 21 ( APC gene (adenomatous polyposis coli))
Explain the role of a first and second hit in the development of familial adenomatous polyposis (FAP)
1st hit - The 1st abnormal gene is acquired in utero
2nd hit - The seconds genetic abnormality in somatic cells that paves the way for the development of polyps
What is p53?
A tumour suppressor gene that causes most cancers