Colorectal Cancer

Question 1

What are the majority of colorectal cancers?

Answer 1

95% adenocarcinomas

Question 2

What is the distribution of colorectal carcinomas?

Answer 2

2/3 colonic
1/3 rectal

Question 3

What are the predisposing factors to colorectal carcinoma?

Answer 3

Neoplastic polyps
IBD
Genetic predisposition
Diet
Alcohol intake
Smoking
Previous cancer

Question 4

What are polyps?

Answer 4

Growths that appear above the mucosa and can be inflammatory, hamartomatous or neoplastic.
Left in situ, polyps carry a risk of malignant transformation

Question 5

What is the presentation of colorectal carcinoma?

Answer 5

Rectal bleeding
Altered bowel habits
Colonic obstruction
Tenesmus
Palpable mass
Weight loss
Anaemia
Abdominal pain

Question 6

What are the tests for colonic cancer?

Answer 6

Bloods: FBC, FOBT, LFT
Sigmoidoscopy/Colonoscopy
MRI/CT

Question 7

What are the 2 methods of staging colorectal cancer?

Answer 7

Dukes Criteria
TNM staging

Question 8

What is Dukes A?

Answer 8

Confined to submucosa

Question 9

What is Dukes B?

Answer 9

Invasion through muscularis mucosae without lymph node involvement

Question 10

What is Dukes C?

Answer 10

Invasion of regional lymph nodes

Question 11

What is Dukes D?

Answer 11

Presence of distant metastases?

Question 12

What is the Tumour part of staging?

Answer 12

Tx- tumour can’t be assessed
Tis- in situ
T1- submucosa
T2- muscularis propria
T3- Serosa
T4- Invasion of adjacent structures

Question 13

What is the Nodal part of staging?

Answer 13

N0- no node spread
N1- metastases in 1-3 regional nodes
N2- metastases in >3 regional nodes

Question 14

What are the surgical treatments of CRC?

Answer 14

Right hemicolectomy
Left hemicolectomy
Sigmoid colectomy
Anterior resection
Abdomino-perineal resection

Question 15

What is right hemicolectomy done for?

Answer 15

Caecal tumours
Ascending colon tumours
Proximal transverse colon tumours

Question 16

What is left hemicolectomy done for?

Answer 16

Distal transverse colon tumours
Descending colon tumours

Question 17

What is sigmoid colectomy?

Answer 17

Sigmoid tumours

Question 18

What is anterior resection done for?

Answer 18

Low sigmoid tumours
High rectal tumours

Question 19

What is abdomino- perineal resection done?

Answer 19

Low rectal tumours

Question 20

When is endoscopic stenting used in CRC?

Answer 20

Palliation in malignant obstruction
Bridge to surgery in acute obstruction

Question 21

Describe an ileostomy stoma

Answer 21

Right iliac fossa
Liquid, looser stools
Spouted

Question 22

Describe a colostomy stoma

Answer 22

Left iliac fossa
Solid stools
No spout

Question 23

When is radiotherapy used in CRC?

Answer 23

Palliation
Pre-op in rectal cancer

Question 24

When is chemotherapy used in CRC?

Answer 24

Adjuvant
Palliation of metastatic disease

Question 25

What tests are involved in population screening for CRC?

Answer 25

FOBT qFIT Flexible sigmoidoscopy Colonoscopy

Question 26

What is FOBT?

Answer 26

Faecal occult blood test (FOBT) uses a chemical indicator that shows a colour change in the presence of blood in the stool

Question 27

What is qFIT?

Answer 27

Quantitative Faecal Immunochemical Test (FIT) Uses antibodies directed against human haemoglobin to detect blood in the stool

Question 28

What groups are at high risk of CRC?

Answer 28

Heritable conditions IBD Familial risk Previous adenocarcinoma Previous Colorectal cancer

Question 29

What are the genetic conditions associated with CRC?

Answer 29

HNPCC (Lynch syndrome) FAP MAP Peutz- Jeghers syndrome

Question 30

What is HNPCC?

Answer 30

Hereditary non-polyposis colorectal cancer Autosomal dominant Due to mutations in mismatch repair genes 1-3% of CRC

Question 31

What is FAP?

Answer 31

Familial adenomatous polyposis Autosomal dominant Due to mutations in APC tumour suppressor gene Causes multiple colorectal adenomas (>100) which undergo malignant transformation

Question 32

What is MAP?

Answer 32

MUTYH- associated polyposis Autosomal recessive Due to variants in MUTYH base excision repair gene

Question 33

What is Peutz- Jeghers syndrome?

Answer 33

Hamartomatous polyps