Colorectal Cancer and Screening Flashcards Preview

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Flashcards in Colorectal Cancer and Screening Deck (18):
1

What fraction of colorectal cancers are colonic and what fraction are rectal?

Two thirds colonic, one third rectal

2

What percentage of colorectal cancers are associated with underlying IBD?

1%

3

What percentage of colorectal cancers have an associated familial risk?

10%

4

What are the risk factors for colorectal cancers?

Age
Male
Previous adenoma/CRC
Diet
Obesity
Lack of exercise
Smoking
Diabetes mellitus
Polyps

5

What do the majority of colorectal cancers arise from?

Pre-existing polyps

6

The majority of colorectal polyps are

adenomas

7

What are polyps?

Benign, pre malignant, epithelial in origin, small growths

8

What are the histological types of polyps?

Tubular (75%)
Villous (10%)
Tubulovillous (15%)

9

What is the basic pathogenesis of the development from polyps into colorectal carcinoma?

Normal epithelium
-> small adenoma
-> large adenoma
-> invasive adenocarcinoma

10

The activation of what oncogenes causes the loss of tumour suppressor genes?

k-ras
c-myc

11

What is the typical presentation of colorectal carcinoma?

Persistent rectal bleeding
Altered bowel opening - particularly diarrhoea
Iron deficiency anaemia
Palpable rectal or lower right abdominal mass
Acute colonic obstruction - if stenosing tumour
Systemic symptoms e.g. weight loss

12

What are the sites of colorectal cancer?

Ascending colon
Transverse colon
Descending colon
Rectum
Anus
Other

13

What is the aim of population screening for bowel cancer?

To detect pre-malignant adenomas or early cancers in the general population

14

What tests might be used to detect pre-malignancy/early malignancy in the general population through screening programmes?

Faecal occult blood test (FOBT)
Faecal immunochemical test (FIT)

15

What other investigations might be done to detect pre-malignancy/early malignancy in bowel cancer?

Flexible sigmoidoscopy
Colonoscopy
CT colonography

16

The Scottish Bowel Screening Programme is shifting from using faecal occult blood test to what modality of testing?

Faecal immunochemical test (FIT)

17

What percentage of colorectal cancers do high-risk groups account for?

Around 15%

18

Give an example of a high risk group for developing colorectal cancer

Hertiable conditions e.g. FAP, HNPSS
IBD
Family history
Previous adenoma/colorectal cancer