Colorectal Carcinoma Flashcards
Common type of patient who gets colorectal cancer?
60+ western male
What are the benign precursors to colorectal cancer?
Colonic adenomas
What is the main characteristic of a colonic adenoma?
Dysplastic epithelium
Large bowel polyps can bleed leading to…
Iron deficiency anaemia
What are the three types of colonic adenoma?
Tubular
Villous
Tubulovillous
What does APC stand for?
Adenomatous polyposis coli
What is APC’s role in cancer?
breaks down beta-catenin, so mutation of APC gene = increased beta-catenin = promotes cell proliferation
Name two other genes involved in colorectal cancer
KRAS
p53
What two dietary factors contribute to an increased risk of colorectal cancer?
low fibre
high refined sugars
What disease increases your risk of colorectal cancer?
IBD
What are your chances of dveloping colorectal cancer if you have a 1st degree relative with it?
1/10
compared to 1/50 with no relative
What commonly used drug is thought to be protective from colorectal cancer?
Aspirin 300mg/day
What are 95% of colorectal cancers?
Adenocarcinomas
Others: lymphoma, GIST, carcinoid
Where do the majority of colorectal cancers occur?
Rectum 35% Sigmoid 25% Caecum and ascending colon 20% Transverse 10% Descending 5%
What are the 5 main presentations of LEFT colorectal cancer
Altered bowel habit PR Mass (60%) Obstruction (25%) Bleeding/mucous PR Tenesmus
What are the 3 main presentations of RIGHT colorectal cancer
Anaemia
Wt Loss
Abdo Pain
What three blood tests would you want to perform in ?colorectal cancer
FBC: Hb
LFT’s: AFP(mets)
Tumour marker: CEA
What types of imaging/scopes would be used in ?colorectal cancer
CXR: lung mets
US liver: mets
CT and MRI: staging
Endoanal US: for staging rectal tumours
Ba/gastrograffin enema: apple-core lesion
Flexi sig(65% of tumours accessible)/colonoscopy
What is the name of the staging criteria used for colorectal cancer
Dukes
What is a Dukes A, and what is its % 5yr survival rate?
Confined to bowel wall - 90% 5yr survival
What is a Dukes B, and what is its % 5yr survival rate?
Through bowel wall but no lymph nodes - 60% 5yr survival
What is a Dukes C, and what is its % 5yr survival rate?
Regional lymph nodes - 30% 5yr survival
What is a Dukes D, and what is its % 5yr survival rate?
Distant mets - <10% 5yr survival
What sort of management do colorectal cancer patients need
MDT
What percentage of colorectal cancer patients are amenable to radical surgery
60%
What test is used to screen for CRC?
Faecal occult blood testing
+ve test -> colonoscopy
What age group qualifies for screening and how often are they tested
60-75
every 2 years
What other screening tests are used for CRC, how often are they used and what age group qualifies?
Flexi sig
Once only
55-60
