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Flashcards in Colorectal Cancer Deck (108)
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1

How does the incidence of colorectal cancer differ from other cancers?

It is the third most common cancer in the UK

2

How does the mortality of colorectal cancer differ from other cancers?

It has the second highest mortality figures of any cancer

3

What is the occurrence of colorectal cancer strongly associated with?

Age

4

What % of presentations of colorectal cancers are in patients in those >60 years?

85%

5

Can colorectal cancers occur in patients 20-30 years of age?

Yes, particularly in inherited cancer syndromes

6

Where do colorectal cancers originate from?

The epithelial cells lining the colon or rectum

7

What is the most common type of colorectal carcinoma?

Adenocarcinomas

8

What are the rarer types of colorectal carcinoma?

Lymphoma
Carcinoid
Sarcoma

9

How do most colorectal cancers develop?

Via a progression of normal mucosa to colonic adenoma (colorectal polyps), to invasive adenocarcinoma

10

How long can adenomas be present before becoming malignant?

10 years or more

11

What % of adenomas progress to adenocarcinomas?

10%

12

What genetic mutations have been implicated in predisposing individuals to colorectal cancer?

Adenomatous polyposis coli (APC) gene
Hereditary non-polyposis colorectal cancer (HNPCC)

13

What is the APC gene?

A tumour suppressor gene

14

What does early APC gene mutation and inactivation result in?

Growth of adenomatous tissue

15

What condition is APC mutation responsible for the development of?

Familial adenomatous polyposis (FAP)

16

What happens in HNPCC?

Mutation to DNA mismatch repair genes lead to defects in DNA repair

17

What does HNPCC commonly account for?

The familial risk associated with colorectal cancer

18

What % of colorectal cancers are sporadic?

Approximately 75%

19

What is meant by sporadic in colorectal cancer?

Developing in people with no specific risk factors

20

What are the risk factors for colorectal cancer?

Age >60 years
Family history
Inflammatory bowel disease
Low fibre diet
High processed meat intake
High alcohol intake
Smoking

21

What are the common clinical features of bowel cancer?

Change in bowel habit
Rectal bleeding
Weight loss
Abdominal pain
Iron-deficiency anaemia

22

When is progressive weight loss present in colorectal cancer?

Only with associated metastasis, or rarely sub-acute bowel osbtruction

23

What symptoms may be present with a right-sided colon cancer?

Abdominal pain
Occult bleeding
Mass in right iliac fossa

24

What symptoms may be present with a left-sided colon cancer?

Rectal bleeding
Change in bowel habit or tenesmus
Mass in left iliac fossa/mass on PR exam

25

When should patients be referred for urgent investigations for suspected bowel cancer?

40 or older with unexplained weight loss and abdominal pain
50 or older with unexplained rectal bleeding
60 or older with iron-deficiency anaemia or changes in bowel habit
Positive occult faecal blood test

26

What are the differential diagnoses for colorectal cancer?

Inflammatory bowel disease
Haemorrhoids
Diverticulitis

27

How can inflammatory bowel disease be differentiated from colorectal cancer?

The average age of onset is younger (20-40years)
Typically presents with diarrhoea containing blood and mucus

28

How is haemorrhoids differentiated from colorectal cancer?

Bright red rectal bleeding covering the surface of the stool
Rarely presents with abdominal discomfort or pain, altered bowel habits, or weight loss

29

How can diverticulitis be differentiated from colorectal cancer?

It is likely to cause systemic features of inflammation

30

What is the UK screening programme for colorectal cancer?

In the UK, screening is offered every 2 years to men and women aged 60-75 years using faecal occult blood home testing kits