Colorectal Cancer

Question 1

Define colorectal cancer

Answer 1

majority of colorectal cancers are adenocarcinomas derived from epithelial cells

Question 2

What percentage of colorectal cancers occur in each part?

Answer 2

66% of new colorectal cancers arise in the colon (43% in the proximal colon and 23% in the distal colon)
30% in rectum

Question 3

What is the greatest risk factor for sporadic colorectal adenocarcinoma?

Answer 3

Increasing age

Question 4

What are the key diagnostic factors for colorectal cancer?

Answer 4

Presence of risk factors
Increasing age
Rectal bleeding
Change in bowel habit
Rectal mas
Anaemia

Question 5

What are uncommon risk factors for colorectal cancer?

Answer 5

+ve family history

abdominal mass

Question 6

What are some uncommon diagnostic factors for colorectal cancer?

Answer 6

Male sex
Abdominal pain
Weight loss
Anorexia
Abdominal distention
Palpable lymph nodes

Question 7

What are some strong risk factors for colorectal cancer?

Answer 7

Increasing age
Adenomatous polyposis coli mutation
Lynch syndrome
MUTYH/MYH-associated polyposis
Harmaromatous polyposis syndromes
IBD
Obesity

Question 8

What are some weak diagnostic factors for colorectal cancer?

Answer 8

Acromegaly
Limited physical activity
Lack of dietary fibre

Question 9

What are the first line investigations for colorectal cancer?

Answer 9

FBC
Liver biochemistry
Renal function
Colonoscopy
CT colonography
Double contrast barium enema
CT scan CAP

Question 10

Why FBC for colorectal cancer?

Answer 10

6% - 10% patients with iron deficiency anaemia have colorectal cancer

Question 11

Why do we do liver and renal function test?

Answer 11

Baseline in assessment of the patient and to assess for future treatments.

normal, often even when liver metastases present

Question 12

When is a colonoscopy performed?

Answer 12

No clinical evidence of bowel obstruction

Sensitive

Allows for biopsy of suspicious lesion and removal of incidental polyps

Question 13

What preparation is required for a biopsy?

Answer 13

Full bowel prep
Oral laxatives
To ensure clear views of the whole mucosa

Question 14

What would a positive colorectal finding be on a colonoscopy?

Answer 14

Ulcerating or exophytic mucosal lesion that may narrow the bowel lumen

Question 15

What to do the presenting symptoms of colorectal cancer depend on?

Answer 15

Size and location of the tumor

Question 16

What are the presenting symptoms of left-sided colon and rectum?

Answer 16

Change in bowel habit
Rectal bleeding
Tenesmus

Question 17

What is Tenesmus and why does it occur?

Answer 17

Due to space occupying tumour in the rectum

It is the sensation of incomplete emptying after defecation

Question 18

What are the presenting symptoms when the right-sided colon is affected?

Answer 18

Presents later
Anaemia symptoms
Weigh loss
Non-specific malaise
Lower abdo pain (rare_

Question 19

Why do 20% of tumours present as an Emergency? And how do they present?

Answer 19

Pain and distention due to:
Large bowel obstruction
Haemorrhage or peritonitis due to perforation

Question 20

What are the signs of colorectal cancer on examination?

Answer 20

Anaemia
Abdominal mass
Low lying may be palpable on DRE
If metastatic: hepatomegaly, ascites

Question 21

What might be seen in colorectal cancer on a double contrast barium enema?

Answer 21

‘Apple core’ strictures

Question 22

What is the treatment to rectal cancer suitable for surgery?

Answer 22

Stage I low risk - local or radical excision

Stage II high risk - radical resection adj. pre-op radiotherapy +/- chemo

Stage II-III - radical resection + pre/post op chemo
OR
Total neoadjuvant therapy

Stage IV - surgical resection, locally ablative procedures, chemoradiotherapy

Question 23

What is the treatment to rectal cancer not suitable for surgery?

Answer 23

Chemo

Adj. VEGF inhibitor or EGFR inhibitor

Adj. Stenting

2nd line
- Alt chemo/targeting therapy regimen

Adj. Stenting