Gastrointestinal Malignancy

Question 1

What is the Duke staging system?

Answer 1

The Duke staging system is a staging system for bowel cancer, it is an alternative to the TNM system.

There are four stages of cancer: Duke’s A-D
The classification depends on size and spread of cancer.

Duke’s A - colonic/rectal mucosa ONLY
Duke’s B - entire bowel wall
Duke’s C - local bowel lymph nodes
Duke’s D - distant metastases (nodes/organs)

Duke’s D is AKA advanced bowel cancer

Question 2

What is the TNM staging system in bowel cancer?

Answer 2

TNM staging: Tumour, Node and Metastases.

T: Size of tumour
T1 - mucosa only
T2 - mucosa to muscularis propria
T3 - mucosa to serosa or adjacent organs (within the visceral peritoneum)
T4 - mucosa to visceral peritoneum (escapes bowel entirely)

N: no. of nodes containing cancer
N0 - none
N1 - 1 to 3 nodes close to bowel
N2 - 4+ nodes more than 3cm from the tumour
Or N2 - nodes connected to main blood vessels of the bowel (mesenteric arteries e.g. sigmoid arteries or inferior mesenteric artery)

M: metastatic spread
M0 - no metastasis
M1 - metastasis

Question 3

Which patients should be put on the urgent two week wait for suspected bowel cancer?

Answer 3

High risk patients:

1. Anyone with 6/52 change in bowel habit and bleeding
2. > 60 and 6/52 change in bowel habit
3. > 60 and 6/52 rectal bleeding
4. Anyone with palpable right sided mass (iliac fossa)
5. Anyone with palpable rectal mass
6. Anyone with unexplained iron deficient anaemia (not from menorrhagia or trauma etc)

Question 4

Considering how large the gap in survival rates is between early and late stage colorectal cancer, how does the NHS try to Circumvent this problem?

Answer 4

The CRC national screening program, this is to try no pick up on adenomas (polyps) before they become carcinomas.

FOBT:
Offered to those age 60 to 74.
Two yearly testing for foecal occult blood (6 samples).

Endoscopy:
Offered at age 55.
One off endoscopy, with removal of any polyps.

Follow up:A positive FOBT result means you are given a further colonoscopy.

10% of those with positive FOBT, have CRC.

NOTE: Beef and beetroot can give a false positive FOBT result.

Question 5

What are the Amsterdam criteria?

Answer 5

The Amsterdam criteria is a risk calculator for a patient harbouring the HNPCC (hereditary non-polyposis colorectal cancer) gene.

The criteria are based on family history and patients age at CRC onset.

High risk factors:
>3 relatives with CRC, spanning 2 generations
First degree relative connecting these relatives
Age of onset <50
FAP has been excluded

Question 6

After provisional diagnosis, how is CRC staged?

Answer 6

1. Endoscopy with sampling for biopsy - HISTOLOGY
2. Local staging: MRI - checks how far through bowel wall it has grown - WALL SPREAD
3. Systemic staging: CT chest/abdomen/pelvis scan - look for any extracolonic disease - METASTASES

Question 7

What are the survival rates for the Duke’s staging of CRC? i.e. A-D

Answer 7

A = 90%
B = 70-80%
C = 50-60%
D = 5-10%

The screening programme picks up 50% of Duke’s A and therefore catching it early massively affects prognosis.