Dysplasia Carcinoma Sequence in Colorectal Cancer Flashcards

1
Q

What patients are most at risk of colorectal cancer?

A

Middle aged to elderly patients with a diet high in red meat and low in folate who are more sedentary and have high body weight

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are adenomatous polyps?

A

precursor lesions for colorectal carcinoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What features of a polyp predict whether it will become cancer?

A

size, villous morphology, high grade dysplasia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are two familial syndromes which can lead to early onset colorectal cancer?

A

Lynch syndrome and familial adenomatous polyposis (FAP)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What percentage of colorectal cancers is due to Lynch syndrome?

A

3%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What percentage of colorectal cancers is due to FAP?

A

1%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What diseases may predispose the patient to early onset colorectal cancer?

A

inflammatory bowel diseases like ulcerative colitis and crohn’s disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What gene mutation is there in FAP?

A

APC gene mutation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the syndrome of FAP?

A

more than 100 adenomatous polyps in the large bowel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the treatment for FAP?

A

total colectomy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does an adenomatous polyp look like histologically?

A

abnormal crypt architecture, crowded cells, enlarged and hyper chromatic nuclei, goblet cell depletion, increased mitotic cells, does not invade beyond the muscularis mucosae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What defines a colorectal adenocarcinoma?

A

When there is invasion beyond the muscularis mucosae and a desmoplastic stromal reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are three genetic pathways leading to colorectal cancer?

A

chromosomal instability, microsatellite instability, CpG island methylator phenotype

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What genetic instability causes Lynch syndrome?

A

microsatellite instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What genetic instability causes FAP?

A

chromosomal instability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which proto-oncogenes are commonly mutated in colorectal cancer?

A

K-RAS and B-RAF

17
Q

Which tumour suppressor genes are commonly mutated in colorectal cancer?

A

SMAD4/SMAD2 and p53

18
Q

What is a sessile serrated polyp?

A

a polyp in the more proximal colon that is more difficult to detect in a colonoscopy

19
Q

What are the macroscopic features of colorectal cancer?

A

typically firm and white, may be necrotic, may be mucoid, may be stenosing if in distal colon

20
Q

What is the typical presentation for an ulcerated colorectal tumour?

A

Anemia

21
Q

How is colorectal cancer staged according to the ACPS system?

A

A- invades muscularis mucosae
B- invades muscularis propria
C- lymph node metastases
D- distant metastases

22
Q

Why is EGFR targeted therapy ineffective for K-RAS and B-RAF mutations?

A

Because it blocks signalling upstream of ras and raf