Colorectal cancer (CRC)

Question 1

Symptoms

Answer 1

Blood in the stools

Mucus discharge

Recent change in bowel habits (constipation more common than diarrhoea)

Alternating constipation with spurious diarrhoea

Bowel leakage when flatus passed

Unsatisfactory defecation (the mass is interpreted as faeces)

Abdominal pain (colicky) or discomfort (if obstructing)

Rectal discomfort

Symptoms of anaemia

Question 2

Investigations

Answer 2

Faecal occult blood (FOBT)

Colonoscopy

Sigmoidoscopy, esp. flexible sigmoidoscopy

CT colongraphy (virtual colonoscopy)—investigation of choice

Barium enema (accurate as a double contrast study) if colonoscopy unavailable

If FOBT is positive—investigate by colonoscopy or flexible sigmoidoscopy.

Question 3

Screening

Answer 3

Based on family history

All people 50–80 yrs: FOBT every 2 yrs.

Question 4

Family history and lifetime risk of colorectal cancer

Answer 4

Family history Lifetime risk

None: population risk 1 : 50

One first-degree relative >45 years 1 : 17

One first-degree and one second-degree relative 1 : 12

One first-degree relative <45 years 1 : 10

Two first-degree relatives (any age) 1 : 6

Hereditary non-polyposis colon cancer 1 : 2

Familial adenomatous polyposis 1 : 1

Question 5

Colonoscopy screening

Answer 5

Mmoderate risk:

every 5 yrs from 50 yrs or 10 yrs younger than when family members presented with CRC or whichever comes first

High risk (guided by clinical genetics team);

Yrly or 2-yrly from 25 yrs for those at high risk

• or even earlier every 12 mths from 10–15 yrs if strong history of familial polyposis

and, in addition, flexible sigmoidoscopy and rectal biopsy for those with ulcerative colitis; has a good prognosis if diagnosed early

Question 6

Management

Answer 6

Early surgical excision is the treatment with the method depending on:

• the site and
• extent of the carcinoma