Colorectal cancer Flashcards
What is the 5 year survival for colorectal cancer?
50%
What percentage of colorectal cancers occur on the left side?
> 60%
Where do colonic cancers arise from?
Mostly from polyps and this means people can have synchronous lesions (multiple cancers in multiple polyps)
What type of cancers are found in the colon and rectum?
Adenocarcinomas
What type of cancers are found in the anus?
Squamous cell carcinomas
How long does it take for a polyp to become a cancer?
3-5 years
Why is a rectal exam important if a patient presents with Blood in stool?
38% of all colorectal cancers are found in the rectum and may be palpated on rectal examination
Where are colorectal metastasis often found?
Liver and lung
What is transcoelomic spread of cancer?
A route of tumour metastasis across a body cavity, such as the pleural, pericardial, or peritoneal cavity.
Peritoneal in colorectal cancer
WHat are the risk factors for colorectal cancer?
IBD (esp UC)
Family history of colorectal cancer or colorectal polyps.
Familial adenomatous polyposis- FAP or lynch syndrome
How does cororectal cancer present?
Emergency - bowel obstruction/bleeding.
Chronic- 3-6 month history of change in bowel habit, Colicky abdominal pain, Iron deficiency anaemia (unexplained), rectal bleeding, weight loss and abdominal mass.
If someone presents with unexplained iron deficiency anaemia, what should you do?
Suggestive of GI bleed somewhere.
They need a OGD and colonoscopy referral. Both at the same time to prevent a delay in diagnosis
Do you get bleeding PR with a cancer in the caecum?
Maybe- would be black.
May not notice any change but may be anaemic.
What is tenesmus?
A felling of incomplete evaculation- common in colorectal cancer.
Do patients with colorectal cancer usually get pain on deffication?
Not normally unless anal or distal rectal cancer
What investigations would you do if you suspect colorectal cancer?
Flexible Colonoscopy (gold standard) Sigmoidoscopy (only to the splenic flexure) if bright red blood. Barium enema- uncommon, radiation, unable to get biopsy. CT colongraphy
When are barium enemas useful?
For strictures, diverticular disease. If not fit fro colonoscopy then the patient is probably not fit for Ba enema either
If you find a cancer on a Sigmoidoscopy what is your next step?
Full colonoscopy as they may have synchronous lesions
When is a CT colonography used?
Staging of bowel cancer.
Detection. Sometimes if the patient has had a hysterectomy or previous abdominal surgey and there is lots of scar tissue preventing colonoscopy. Still requires bowel prep and air being pmped into the bowel.
How large does a lesion need to be to be detected on CT?
> 5mm