21. Colorectal Cancer Flashcards
What does the word emaciated mean
Abnormally thin or weak; especially because of illness or lack of food
What are the common causes of fresh blood in the stool
o Haemorrhoids
o Acute anal fissure (following trauma or severe constipation) – small tear in the lining of the anus
o Colo-rectal neoplasms
o Acute proctitis- inflammation of lining of the inner rectum
o Inflammatory bowel disease
what does fresh bleeding usually suggest
The rectum or the anal Canal is the source of the bleeding
If there is bleeding from further up the GI tract (colon, small intestine or stomach) what does the stool look like
blood is mixed in with the stool and presents as melaena
what is an acute anal fissure
there is a break in the skin of the anal canal and associated with severe pain
- usually when passing hard faces sometimes with bright red anal bleeding
Which direction do fissures usually extend and why
usually extend from anal opening and usually directed posteriorly in the midline probably because the anal wall is poorly supported posteriorly
How common is colorectal cancer
3rd most common cancer after breast and lung
2/3rd in the colon and a 1/3rd in the rectum
What is the most common area of the colon to be affected by cancer
recto-sigmoid colon is most common
caecum is the second most common
What does -stomy mean
this is an operation which creates ‘stomas’ or an artificial opening into a hollow organ
What is the difference between an ileostomy and a colostomy
ileostomy is an opening into the small bowel
colostomy is an opening into the large bowel
What aerate risk factors fro colorectal cancer
FH other cancers age IBD diet (red meat, low fibre)
what are the symptoms of colorectal cancer
- Change in bowel habit (usually to more loose and frequent stools)
- Weight loss
- PR bleeding
- Tenesmus (feeling of full rectum even after opening bowels)
- Iron Deficiency Anaemia (microcytic anaemia with low ferritin)
- Bowel obstruction
Why does IDA on its own without any other explanation (ie menstruation) indicate a 2 week wait referral
GI malignancies such as colorectal cancer can cause microscopic bleeding (not visible one stools) that eventually lead to IDA
what is the gold standard investigation for colorectal cancer
colonoscopy which can include biopsy or tattooing (to mark for surgery) of suspicious lesions
What is the use of carcinomembryonic antigen (CEA)
it is a tumour marker blood test for bowel cancer
not. useful in screening
useful in predicting relapse of previously treated bowel cancer
if a patient is less fit for colonoscopy what alternative is there
CT colonography which is where they have a CT with bowel prep and contrast to visualise the colon
In the Dukes classification of colorectal cancer what does Dukes A mean
confined to mucosa and part of the muscle of the bowel wall
In the Dukes classification of colorectal cancer what does Dukes B mean
extending through the muscle of the bowel wall
In the Dukes classification of colorectal cancer what does Dukes C mean
lymph node involvement
In the Dukes classification of colorectal cancer what does Dukes D mean
metastatic disease
Dukes is being replaced by the TNM classification:
- what does TX mean
unable to assess size
Dukes is being replaced by the TNM classification:
- what does T1 mean
submucosal involvement (non further than inner layer of the bowel)
Dukes is being replaced by the TNM classification:
- what does T2 mean
involvement of muscularis propria (grown into the muscle layer of the bowel wall)
Dukes is being replaced by the TNM classification:
- what does T3 mean
involvement of the subserosa (outer lining of the bowel waal or into organs or body structures next to the bowel)
Dukes is being replaced by the TNM classification:
- what does T4 mean
spread directly to other tissues / peritoneum (other parts of the bowel, other organs or body structures near the bowel, or broken thorugh the membrane covering the outside of the bowel)
Dukes is being replaced by the TNM classification: what does the following mean; Nx N0 N1 N2
- NX – unable to assess nodes
- N0 – no nodal spread
- N1 – spread to 1-3 nodes
- N2 – spread to >3 nodes
Dukes is being replaced by the TNM classification:
what does the following mean;
M0
M1
- M0 – no metastasis
* M1 – metastasis
Treatment of colorectal cancer is taken by MDT meeting and is based on clinical condition, general health, staging radiography, histology and patient wishes;
give some options
• Options are surgical resection, chemotherapy, radiotherapy and palliation in any combination
Tell me about the principles of bowel cancer resection
- what is the purpose of a colectomy
- why is laparoscopic procedures preferred
- what does a resection involve
- Colectomy can be curative or palliative
- Laparoscopic approaches give better recovery and fewer complications
- Involves removing the tumours and creating an end to end anastomosis (chopping out bowel and sewing the remaining bits together)
What is a covering loop ileostomy
- how long is it usually left before being reversed
- where is it usually located
- A temporary ileostomy created to protect a distal anastomosis
- Typically left for 6-8 weeks to allow healing of the anastomosis, after which is it reversed
- “Loop” refers to it being the two ends (proximal and distal) of a section of small bowel being brought out onto skin
- Proximal end (the productive side) has turned inside out to form a spout to protect the surrounding skin
- Usually located lower right side of abdomen
What are the complications of bowel cancer resection
- Bleeding / infection / pain
- Damage to nerves, bladder, ureter or bowel
- Post op ileus
- Anaesthetic risks
- Conversion to open
- Anastomotic leak / failure
- Requirement for a stoma
- Failure to remove the tumour
- DVT/PE
- Hernias
- Adhesions
What is a right hemicolectomy used to remove (ie which location)
used to remove tumours of the caecum, ascending and proximal transverse colon
what is a left hemicolectomy used to remove (ie which location)
used to remove tumours of the distal transverse and descending colon
what is a sigmoid colectomy used to remove
tumours of the sigmoid colon
what is an anterior resection used to remove and what does it preserve
Anterior Resection is used to remove tumours of the low sigmoid colon or higher rectum
– autonomic nerves preserved
What is an abdominoperineal resection (APR) used to remove and what does this surgery involve
used to remove tumours of the lower rectum. It requires removing the rectum and anus (plus or minus the sigmoid colon) and suturing over the anus. It leaves the patient with a permanent colostomy
Once a patient has had surgery to cure their disease they are followed up with the following at what intervals;
- CT TAP
- colonoscopy
- CEA
CT TAP at 1 and 2/3 years
colonoscopy at 1 and 5 years
CEA 6 monthly for 3 years
Explain an ileostomy or colostomy to a patient
look at page 4 of notes
give some differentials of rectal bleeding
o Fissure in ano o Haemorrhoids o IBD o Gastroenteritis o Other causes of anaemia o Malabsorption (pancreatic insufficiency, coeliac) o Sexually transmitted infections o Other masses eg bladder, uterus, ovary o Anal cancer o Other causes mass in rectum (eg cervix/prostate)
tell me about the CRC national screening programme
- based on faecal occult blood test (FOBT) and colonoscopy
- done if you are between 60-74 every 2 years
- may not have CRC but could have polyps which have potential to turn into CRC
- an additional one off test called a bowel scope screening is being introduced in England and is offered to men and women at the age of 55
What is one of the key genes responsible for bowel cancer
APC gene mutation and there is a genetic condition called FAP (familial adenomatous polyposis)
- other mutations are in the K ras gene and P53 which is a tumour suppressor gene
What is hereditary non-polyposis colorectal cancer (HNPCC)
inherited mutation in MMR gene and this is an issue with the spell checking and so the replication errors aren’t fixed
- This leads to an earlier onset 30s-50s and has a rapid adenoma-carcinoma progression
o This is why family history is important
Tell me about an ileostomy
- is it spouted or not
- are they often in the RIF or LIF
- is there continuous effluent or periodic function
- is the production liquid or solid
Ileostomy: spouted, often RIF, continuous effluent, liquid
Tell me about an Colostomy
- is it spouted or not
- are they often in the RIF or LIF
- is there continuous effluent or periodic function
- is the production liquid or solid
Colostomy: not spouted, often LIF, periodic function, solid
what is the following colonic cancer prognosis for Dukes A-D
- Dukes A: 90%
- Dukes B: 70-80%
- Dukes C: 50-60%
- Dukes D: 5-10%
what is the premalignant condition where patients have polyps in the colon which have a high probability of undergoing malignant transformation
• Familial polyposis coli (FPC)
- may occur as a result of the mutation in APC gene which is autosomal dominant
- will have parent with similar condition
mutation in which gene may also predispose someone to similar condition of FPC however this one is inherited via an autosomal recessive nature
MUTYH gene
what are the typical features of a malignant ulcer in the colon
fleshy/everted edges
what does a malignant adenoma look like under histology
dysmorphic/polymorphic nuclei
