Colorectal cancer

Question 1

What are the most commonest types of colorectal cancer?

Answer 1

rectal: 40%
sigmoid: 30%
descending colon: 5%
transverse colon: 10%
ascending colon and caecum: 15%

Question 2

What are the 3 types of colorectal cancer?

Answer 2

sporadic (95%)
hereditary non-polyposis colorectal carcinoma (HNPCC, 5%)
familial adenomatous polyposis (FAP, <1%)

Question 3

Patients with HNPCC are at risk of getting which cancers?

Answer 3

Colon
Endometrial
Pancreatic

Question 4

What is the Amsterdam criteria for HNPCC diagnosis?

Answer 4

at least 3 family members with colon cancer
the cases span at least two generations
at least one case diagnosed before the age of 50 years

Question 5

What are the types of resection used for colonic cancer sites?

Answer 5

Right hemicolectomy- Caecal, ascending or proximal transverse colon
Left hemicolectomy- Distal transverse, descending colon
High anterior resection- sigmoid colon
Anterior resection- upper rectum
Anal verge- abdomino-perineal excision of rectum

Question 6

What’s the best marker to use in bowel cancer?

Answer 6

CEA

Question 7

What are the stages of colorectal cancer?

Answer 7

Stage 0: in situ, not passed mucosa
Stage 1: beyond mucous, no lymph nodes
Stage 2: entire wall, may reach nearby organs, no lymph nodes
Stage 3: lymph nodes, no distant organs
Stage 4: metastatic, (colon-liver) (rectum- lungs)

Question 8

What are the risk factors for colorectal cancer?

Answer 8

Elderly and make
IBD
Smoking 
Red meat
Lack of fibre
Obesity 
FAP
HNPCC

Question 9

What are the symptoms of tumours in the ascending colon?

Answer 9

Grow beyond mucosa 
Pain and weight loss
No bowel obstruction 
Can grow large 
Late diagnosis
Ulceration and bleeding- anaemia

Question 10

What re the symptoms of tumours in the descending colon?

Answer 10

Infiltrating masses
Ring shaped 
Lumen narrowing 
Haematochezia 
Early symptoms

Question 11

How is colorectal cancer diagnosed

Answer 11

Colonoscopy
Fecal occult blood testing
Elevation in CEA (not specific)
Barium enema- apple core sign (descending)

Question 12

Colorectal cancer genetic aetiology

Answer 12

Familial adenomatous polyposis (FAP): <1%, APC tumour supressor mutations
Hereditary non-polyposis colorectal cancer (HNPCC): <5%, germline mutations in mismatch repair genes

Question 13

Indications for a 2WW referral for colorectal carcinoma

Answer 13

> 40y with…
Rectal bleeding/change in bowel habit >6w
45y & persistant rectal bleeding with no evidence of benign anal disease
IDA (Hb<10g/dl) without an obvious cause
Palpable abdominal/PR mass