Colorectal cancer

Question 1

What are the risk factors for sporadic cases of colorectal cancer?

Answer 1

Age
Male
Previous adenoma/colorectal cancer
Environmental influences- diet, obesity, lack of exercise, smoking, diabetes mellitus

Question 2

What are the risk factors for colorectal cancer?

Answer 2

Familial risk
Inherited conditions
Underlying IBC

Question 3

What do the majority of colorectal cancers arise from?

Answer 3

Existing colorectal polyps

Question 4

What are colorectal polyps?

Answer 4

Protuberant growths with a variety of histological types, which can be epithelial or mesenchymal, benign or malignant

Question 5

What are adenomas?

Answer 5

Benign, premalignant, epithelial growths which can develop to tumours

Question 6

How do adenomas develop to tumours?

Answer 6

Activation of oncogenes
Loss of tumour suppressor genes
Defective DNA repair pathway genes

Question 7

What are the main histological types of adenomas?

Answer 7

Tubular

Villous

Question 8

What is the usual presentation of colorectal cancer?

Answer 8

Rectal bleeding
Altered bowel habits
Iron deficiency anaemia- in men and non menstruating women
Palpable rectal or lower right abide mass
Acute colonic obstruction
Weight loss, anorexia

Question 9

What investigations are carried out for colorectal cancer?

Answer 9

Colonoscopy- gold standard
Imaging- barium enema, CT colonography
CT abdo/pelvis

Question 10

What are the risks of colonoscopy?

Answer 10

Perforation

Bleeding

Question 11

What are the benefits of a colonoscopy?

Answer 11

Diagnostic and therapeutic-
Biopsy can be taken
Polypectomy can be carried out

Question 12

How is colorectal cancer staged?

Answer 12

CT
MRI for rectal tumours
PET or rectal endoscopic ultrasound

Question 13

What classification systems are used for colorectal cancer?

Answer 13

TMN

Dukes

Question 14

What is Dukes classification of colorectal cancer?

Answer 14

A= tumour confined to mucosa
B= tumour extended through mucosa to muscle layer
C= involvement of lymph nodes
D= distant metastases

Question 15

What are the treatment options for colorectal cancer?

Answer 15

Surgery
Chemo
Radiotherapy

Question 16

How is Dukes A cancer treated?

Answer 16

Endoscopic or total resection

Question 17

What does operative procedure depend on?

Answer 17

Site, size and stage of tumour

Question 18

What surgical procedures can be used to treat colorectal cancer?

Answer 18

Tumour or bowel resection
Stoma formation
Removal of lymph nodes for histological analysis
Partial hepatectomy for metastases

Question 19

How is chemotherapy used in colorectal cancer?

Answer 19

Advanced B cancer onwards
Adjuvant therapy
Clears any micrometastases

Question 20

How is radiotherapy used in colorectal cancer?

Answer 20

Rectal cancer
Neoadjuvant therapy
Shrinks tumour before resection

Question 21

What is the 5year survival of each of the Dukes classifications?

Answer 21

A 5 year survival 83%
B 5 year survival 64%
C 5 year survival 38%
D 5 year survival 3%

Question 22

How is screening down in the general population?

Answer 22

5 yearly FOB test for 50-74 year olds

Question 23

What is the aim of screening in the general population?

Answer 23

Detect premalignant carcinomas and early cancers

Question 24

Who are high risk groups for colorectal cancer?

Answer 24

Heritable conditions
IBD
Familial risk
Previous adenomas
Previous colorectal cancer

Question 25

What inheritable conditions can cause colorectal cancer?

Answer 25

Familial adenomatous polyposis | Hereditary non polyposis colorectal cancer

Question 26

What does familial adenomatous polyposis cause?

Answer 26

Multiple adenomas throughout colon | Extracolonic manifestations

Question 27

What is done for those with familial adenomatous polyposis?

Answer 27

Annual colonoscopy from age 10-12 Prophylactic protocolectomy at age 16-25 NSAIDs chen-prevention- reduces polyp number and prevents re-occurance of higher grade adenomas

Question 28

What does hereditary non-polyposis cause?

Answer 28

Early onset right sided colorectal cancer

Question 29

What is hereditary non-polyposis associated with?

Answer 29

``` Cancers in colorectal Endometrium Geritourinary Stomach Pancreas ```

Question 30

What screening is done for those with hereditary non polyposis?

Answer 30

Colonoscopy every 2 years

Question 31

What screening is done for those with IBD?

Answer 31

Colonoscopy 10 years after diagnosis then repeated at intervals depending on duration, extent and activity of inflammation

Question 32

What screening is done for those with a high familial risk?

Answer 32

5 yearly colonoscopy from 50 years

Question 33

What is done for those with a low familial risk?

Answer 33

Colonoscopy at 55

Question 34

What screening is done for those with a history of colorectal cancer?

Answer 34

5 yearly colonoscopy