Colorectal Cancer

Question 1

what are 2 types of colorectal neoplasia?

Answer 1

1) benign
- adenoma

2) malignant
- adenocarcinoma

Question 2

what are 4 types of colorectal polyps?

Answer 2

• inflammatory
• hamaromatous
• metaplastic
• neoplastic (adenoma)

Question 3

what are 2 genes associated with cancer?

Answer 3

1) oncogenes
- when normal promotes cell growth and division
- when mutation causes excess cell growth and division

2) tumour supressor genes
- when normal suppress cell growth and division
- when mutated allow cell growth and division

Question 4

what are the genetics involved in colorectal cancer?

Answer 4

• mutations in APC (adenomatous polyposis coli)
  = 100% risk of developing bowel cancer
• mutation of p53 gene
  = it has a role in repair of DNA
• predisposing disease
  = long standing IBD
  = ulcerative colitis > crohns
  = adenomatous polyps

+ APC + K-ras + p53 + 18q loss

Question 5

describe autosomal dominant inheritance of colorectal cancer?

Answer 5

FAP
= mutation in APC gene

HNPCC
= mutation in DNA mismatch repair gene

Question 6

what are causes of bowel cancer?

Answer 6

1) environment
2) genetic factors
3) predisposing conditions

• older age
• low intake of fibre
• high intake of fats sugar, red meat, processed meats
• obesity
• smoking
• lack of physical exercise
  = exercise = AMPK = glucose uptake by muscle = decreased cell turnover

Question 7

what are the 3 macroscopic appearances of colorectal cancer?

Answer 7

• polypoidal
• ulcerative
• annular

Question 8

what are the 2 types of appearances of adenomas?

Answer 8

• tubular

- villous

Question 9

what are the 3 types of appearances of adenocarcinoma?

Answer 9

• well differentiated
• moderately differentiated
• poorly differentiated

Question 10

what are ways of spreading

Answer 10

• direct spread
  = local via adjacent structures
• lymphatic spread
  = pericolic nodes
  = peri-vascular nodes
• blood borne spread
  = liver
  = lung
• trans-coelomic spread (rare)
  = peritoneal cavity

Question 11

how can you pick up colorectal cancer?

Answer 11

1) bowel screening programme

2) urgent - via SOPD or endoscopy
= urgent referral from GP with ‘reg flag symptoms’

3) emergency
- obstruction
= distension
= constipation
= pain
vomiting

• rectal bleeding
• palpable mass
• perforation

Question 12

how can you stage cancer?

Answer 12

1) dukes’ staging
= A, B, C, D
D - distant mets

2) TNM
T = tumour
N = (lymph) nodes
M = metastases

Question 13

describe the TNM staging system?

Answer 13

T1 = sub-mucosa
T2 = not muscle
T3 = through muscle
T4 - adjacent structures (including peritoneum)

N0 = no lymph node involvement 
N1 = < 3 nodes involved
N2 = > 3 nodes involved

M0 = no distant mets
M1 = distant mets

Question 14

how does right sided cancers present?

Answer 14

• unexplained iron deficiency anaemia
• persistent tiredness
• persistent and unexplained change in bowel habits
• unexplained weight loss
• abdominal pain (colicky nature)
• lymph in abdomen

Question 15

how does left sided cancer present?

Answer 15

• rectal bleeding
• feeling of incomplete emptying, tenesmus
• worsening constipation

Question 16

what are general, abdomen and rectum findings with colorectal cancer?

Answer 16

General
= anaemia
= cachexia
= lymphadenopathy

Abdomen
= mass
= hepatomegaly
= distension

Rectum
= mass
= blood

Question 17

how would you diagnose primary disease?

Answer 17

• barium enema
• CT colonography
• sigmoidoscopy
• colonoscopy
• Faecal occult blood testing (FOBT)

Question 18

how would you treat obstruction?

Answer 18

• colostomy alone
• resection + colostomy
• resection + anastomosis
• stenting

Question 19

what investigations could be used to stage colorectal cancer?

Answer 19

Lungs
= CT

Liver
= CT

Primary rectal cancer
= MRI

Question 20

what do you do after cancer has been diagnosed?

Answer 20

• histopathology confirmation
• cancer staging
  = CT chest/abdo/pelvis
  = MRI for rectal cancer
• MDT
• surgery/pailiation
• FOU

Question 21

how do you treat colorectal cancer?

Answer 21

1) surgery
2) radiotherapy
3) chemotherapy

Question 22

what are examples for surgery of colonic cancer?

Answer 22

• right hemicolectomy
• extended right hemicolectomy
• transverse colectomy
• left hemicolectomy
• sigmoid colectomy
• subtotal colectomy

Question 23

what are 3 surgeries for rectal cancer?

Answer 23

• abdomino-perineal excision
• anterior resection
• local excision

Question 24

what are 2 types of radiotherapy for rectal cancer?

Answer 24

1) adjuvant
- pre or post operative
- reduces local recurrence after rectal excision

2) palliative
- inoperable primary rectal cancer
- recurrent rectal cancer

Question 25

describe the chemotherapy used fo colorectal cancer?

Answer 25

• 5-fluorouracil (5-FU) or capecitabine
• Adjuvant for Stage C
  5-10% absolute improvement in survival
• For advanced disease
  = median survival advantage of ~5 months
  = new drugs – oxaliplatin, irinotecan
  = Biological agents – cetuximab, bevacizumab

Question 26

LECTURE 2 - therapy of colorectal cancer

Answer 26

LECTURE 2 - therapy of colorectal cancer

Question 27

what are 2 ways in which surgery can be carried out?

Answer 27

• open surgery
• laparoscopic surgery
• robotic surgery

Question 28

post operatively what would you offer?

Answer 28

• chemo/radiotherapy depending on stage
• Follow-up;
  = CT
  = CEA
  = colonoscopy

Question 29

what are 4 palliation options for colorectal cancer?

Answer 29

• stenting
• palliative radio/chemo
• de-functioning
• bypass