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
What is the typical picture of cancer on a barium enema?
Apple coring
What medication can be given to relax the bowel for CT or colonoscopy?
Buscapan
What is the toblerone sign?
A sign that you are in the transverse colon
What causes the pain for patients at colonoscopy?
Stretching of the bowel wall as it has stretch receptors. You must pump air int the bowel to see it .
You find a polyp or suspicious lesion at colonoscopy. Where do you take your biopsy from?
Edges as the middle will be full of necrosis
What is the Haggitt level?
A classification system for pedunculated polyps. Level 0 (cancer in the very top of the polyp) -4 (cancer in the mucosa) Level 3-4 there is a 25% chance of cancer in lymph nodes and they will need surgery.
Why do you tattoo distal to the site where the polyp was removed?
So that you can identify where the polyp was incase histopathology find cancer and then you need to do surgery to remove some of the bowel
You identify a colorectal cancer at colonoscopy. WHat next?
Tell the patient.
CT for staging of disease.
Histopathology confirmation in 2-3 weeks.
MDT
Surgery and follow up depending on what is found at surgery and pathology.
How is colon cancer staged?
CT chest/abdo/pelvis
How is rectal cancer staged?
Rectal MRI- the mesorectal facia is full of lymph nodes.
What is the plan if the patient has liver or lung mets?
Fit and healthy patient.
Have chemo/radiotherapy to down stage the metastasis and then operate later to remove the cancer.
This can also be done in rectal cancer to down stage the disease.
What is HIPEC?
Hyperthermic intra-peritoneal chemotherapy
How is HIPEC used?
Pour chemotherapy into the peritoneum for 45-60 minutes if removing liver mets and this should help prevent recurrence of the cancer
So you need to surgically remove a cancer. What determines how much of the bowel is removed?
Blood supply- SMA and IMA
What is APR surgery?
Abdominoperineal resection- left with a permanent colostomy bag.
What are the advantages of laproscopic surgery?
Less scarring and fistulas and adhesions inside. You can operate again if needed.
Quicker recovery for the patient and less chance of infection
Can see more and get into more places.
What is TME surgery?
Total mesorectal excision- this is to remove all rectal cancers and all the lymph nodes in the mesorecal fascia
What is the follow up for patients cured of colorectal cancer?
CT at 1 and 2 years
Regular colonoscopy
Would you ever offer a liver transplant to a patient with liver mets?
No- to much of a raik the new liver will get cancer.
What is the CEA blood test used for?
Taken before cancer removed and regularly during follow up. The CEA is raised in some colorectal cancers but can also be raised in other things eg smoking and pregnancy.
What is a benign neoplasia in the bowel called?
Ademoma
What are the types of polyps?
Inflammatory,
Hamartomatous
Metaplastic
Neoplastic
What is often the first gene mutation in colorectal carcinoma?
And then the ones that follow
APC gene
kRAS
p53
18q loss
What are the two most common types of adenoma?
Villous and tubular
What is dukes stage A, B, C and D?
A = Tumour confined to mucosa
B = Tumour growth into the muscularis propria (1) or through muscularis propria (2)
C = Tumour spread to 1-4 regional lymph nodes (1) or 5+ (2)
d) Distant metastasis
In TNM staging for bowel cancer, What is T1-4?
1 = Submucosa only 2 = Into muscularis mucosa 3 = through muscularis mucosa 4 = Adjacent structure invasion (organs/peritoneum)
In TNM staging for bowel cancer, What is N0-2?
0 = no lymph node involvement 1 = <4 lymph nodes 2 = 4+ lymph nodes
What is the mutation in FAP?
Mutation in APC gene
What is the mutation in lynch syndrome?
Mutation in DNA mismatch repair gene
What is Faecal Occult Blood Testing (FOBT) used for?
Bowel cancer screening.
All 50-75 years olds in scotlant invited to take part every 2 years- completed at home. If positive they will be offered colonoscopy
