carcinoma of the colorectal

Question 1

4 types of polyps

Answer 1

neoplastic
haemartomatous
inflammatory
unclassified: hyperplastic

Question 2

which type of polyp has the highest risk of malignancy

Answer 2

neoplastic

Question 3

what are the solitary and multiple types of neoplastic polyps

Answer 3

solitary=adenoma
-tubular
-tubulovillous
-villous
multiple=FAP

Question 4

what are the solitary and multiple haemartomatous polyps

Answer 4

solitary
-juvenile polyp
-peutz-jeghers polyp
multiple
-juvenile polyposis
-peutz jeugher 
-cronkhite-canada
-cowden's disease

Question 5

what are the solitary and multiple inflammatory polyps

Answer 5

solitary=

• benign lymphoid polyps
• pseudo-polyps

multiple

• benign lymphoid polyposis
• pseudo-polyposis (UC)

Question 6

unclassified types of polyps

Answer 6

solitary

• metaplastic
• hyperplastic
• lipoma
• neurofibroma

multiple

• multiple metaplastic polyps
• MAP (MYH assoc. polyposis)

Question 7

colorectal adenoma polyps risk of malignancy

Answer 7

• tubular
• tubularvillous
• villous: most

Question 8

evidence for adeno-carcinoma sequence

Answer 8

• high prevalence of adenomas in patients with high cancer rate
• fap
• similar distribution colon and rectum
• age specific peak
• focci of carcinoma detected adenoma
• focci of adenoma common in early carcinoma
• future cancer risk relates to total adenoma load
• polypectomy assoc. with reduced cancer incidence

Question 9

genes involved in first stage of adeno carcinoma sequence

Answer 9

1. first hit to the APC gene ie hereditary
2. second hit to the APC gene-somatically
3. beta catenin signalling= mucosa at risk- methylation abnormalities

Question 10

where is APC gene located

Answer 10

APC at 5q21

Question 11

gene involved in formation of adenoma in adenocarcinoma sequence

Answer 11

1. kRAS-oncogene

Question 12

genes involved in formation of adenocarcinoma

Answer 12

TP53
LOH
SMAD 2 and 4- tumour suppressor

Question 13

gene involved in additional mutations

Answer 13

telomerase

Question 14

m:f for colon and rectum cancer

Answer 14

f>m for colon

m>f for rectum

Question 15

age peak for colorectal cancer

Answer 15

75-79

Question 16

what number is it for cancer causes of death

Answer 16

2nd

Question 17

risk factors for colorectal cancer

Answer 17

western diet
-red meat
-high fat
-low in fibre
lifestyle
-smoking 
-exercise 
-beer (rectal cancer)
IBD
-pan UC 30% at 30 yrs
-CD
genetic disposition
-HNPCC
-FAP
-PJS
-JPS

Question 18

what is FAP and inheritance

Answer 18

autosomal dominant with penetrance
-inactivating mutation of APC gene (5q21) adenomatous polyposis coli gene
-benign adenomas but risk malignancy
1% population

Question 19

amsterdam criteria for HNPCC

Answer 19

hereditary non polyposis colorectal cancer

• > 3 family members with histologically proven colorectal cancer
• one relative a first degree relative to the other two
• > 2 generations affected
• age at onset <50 in at least one family member
• uterine cancer in one or more relatives acceptable as part of a 3 member family

Question 20

mutations in dna mismatch repair gene

Answer 20

msh2
mlh1
msh6
pms2

Question 21

lifetime risk for mismatch mutation repair genes

Answer 21

80 males

30% females

Question 22

hnpcc genetics

Answer 22

autosomal dominant
1.microsatellite instability
-defect in MLH1 promoter
-cells accumulate 
-keep the repeating defect
often in CAT cytosine adenine tandem microsatellite gene

Question 23

types of microsatellite mutations

Answer 23

missense: diff protein
nonsense: stop
insertion
deletion
duplication
frameshift: non functional
repeat expansion: nucleotide repeats

Question 24

colorectal cancer presentation

Answer 24

obstruction
perforation
bleeding
localised pain
altered bowel habits
rectal bleeding
colicky pain
anaemia
anorexia
weight loss
malaise
flactulence

Question 25

where abouts in the colon is colorectal cancer found commonly

Answer 25

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

Question 26

screening for colorectal cancer and investigations

Answer 26

• fobt faecal occult blood test at 50
• colonoscopy
• surveillance hnpcc, ibd, fap
• enema
• x-ray
• ct
• dre

Question 27

main tumour marker for colorectal cancer

Answer 27

CARCINOEMBYRONIC ANTIGEN

Question 28

what is harmann’s procedure

Answer 28

resection of the rectosigmoid colon with closure of the anorectal stump and formation of end colotomy

Question 29

surgical options for colorectal cancer

Answer 29

segmental excision
-colectomy and ileorectal anastomosis
-then either a restorative rectal excision or colonic pouch
hartmann’s procedure

• right hemicolectomy
• extended right hemicolectomy
• left hemicolectomy
• anterior resection down to rectum

Question 30

3 macroscopic types of colorectal cancer

Answer 30

• stenosing
• ulcerating
• proliferative

Question 31

Duke’s cancer staging A-D

Answer 31

a=limited to bowel wall
b=through full thickness of bowel wall
c1=regional lymph nodes
c2=apical lymph nodes
d=distant metastasis

Question 32

dukes staging survival meaning for a and d

Answer 32

a=95%

d=<5%

Question 33

what drug is used for colorectal cancer chemotherapy and what is it

Answer 33

capecitabine (thymidylate synthase inhibitor) changes in fluorouracil in the body

Question 34

2nd line chemo colorectal agents 3

Answer 34

cetuximab
bevacizumab
temozolomide

Question 35

colonic cancer maker

Answer 35

carcinoembryonic antigen

Question 36

screening test for bowel cancer and what age in Scotland is it offered between

Answer 36

faecal immunochemical test

50-74

Question 37

stats from colonoscopy first time after positive fit

Answer 37

• 5 out of 10 at colonoscopy normal colonoscopy
• 4 out of 10 have polyps removed premalignant
• 1 out of 10 have cancer