Colorectal cancer Flashcards
Which environmental factor plays a major role in the aetiology of colorectal cancer?
Diet
What % of colorectal cancers are associated with a genetic predisposition syndromes for example FAP or HNPCC (lynch syndrome)?
<8%
What pathology are the majority of colorectal cancers?
Adenocarcinoma
In rectal cancer, what is there a propensity for the tumour to do?
For it to infiltrate laterally into the peri-rectal fat and lymph nodes
What is the main curative therapy for colorectal cancer?
Surgery
What is required pre-operatively to resection of colorectal cancer? (5)
- Knowledge of precise site and extent of tumour
- Full colonoscopy and air-contrast barium enema
- CT/US liver
- MRI of pelvis to stage rectal cancer
- Peri-operative antibiotics and thromboembolic prophylaxis are mandatory
In a primary resection, what needs to be removed?
Bowel segment and its lymphatic field
If resecting rectal cancer, what need to be removed?
Total excision of the mesorectum (TME)
How many cases of colorectal cancer are there each year in the UK?
41,200
How many deaths are there per year due to colorectal cancer?
16,000
How do colorectal cancers develop?
From polyps - adenomatous polyps
If polyps are found, why are they removed?
To prevent later development of cancer
Colorectal cancer can present as rectal bleeding, but what are the other causes of rectal bleeding? (5)
- Haemorrhoids
- Anal fissures
- Gastroenteritis
- Trauma
- Anticoagulants
Of all the people who present to GP with rectal bleeding, what % have colorectal cancer?
3.6%
What are the red flag symptoms for colorectal cancer? (6)
- Change in bowel habits
- Weight loss
- Rectal bleeding
- Abdominal pain
- Mucous/blood PR (DRE)
- Anorexia
What 4 key questions need to be asked when taking a history about change in bowel habits?
- Do they get up at night to open their bowels? (this is highly unusual)
- Are they incontinent?
- Is it stopping them from doing things?/interfering with their everyday life?
- Associated with any other symptoms e.g. bleeding/mucous/pain
What should you look out for on examination in suspected colorectal cancer? (4)
- Loss of weight
- Signs of anaemia
- Abdominal mass
- Mass on rectal examination
If patients are suspected of having colorectal cancer, with clear red flag symptoms, what test/investigations are they referred for? (1)
Colonoscopy/flexible sigmoidoscopy
If the patient is unfit/unwell, multiple co-morbidities, or their symptoms aren’t red flags - what will the referral be for?
To be seen by a colorectal surgeon or gastroenterologist within 14 days
What should a GP do before referring directly in suspected CRC? (3)
- Blood tests (FBC, ferritin)
- Examination
- DRE
When is screening for CRC offered?
Every 2 years for men and woman aged between 60-74
What does the CRC screening test comprise of?
An invitation letter and kit with 3 separate samples need to be given for faecal occult blood (FOB) with results 2 weeks later
What does an emergency presentation of CRC normally refer to? (4)
A&E presentation with:
- Obstruction
- Perforation
- Bleeding
- Abdominal pain
What is the distribution of occurrence of CRC within the colon?
1/3 in the rectum
1/3 on the left side
1/3 remainder of the colon
What is the difference in terms of treatment for colon and rectal cancer?
Colon cancer: local recurrence uncommon, neo-adjuvant treatment is currently experimental but generally patients do not receive this, and go straight to surgery e.g. hemicolectomy
Rectal cancer: local recurrence is more common, so neoadjuvant treatment is required unless the patient is low risk. If the patient is moderate risk, they will receive radiotherapy alone and then surgery, whereas if they are high risk they will receive radiotherapy and chemotherapy and then surgery.
In TNM staging, there is also a V and R stage, what do these refer to?
V = vascular R = completeness of surgical resection
A patient with T3, N2, V1, R0, is classed as high risk, whats treatment will they hopefully benefit from?
Chemotherapy
What will the staging look like for a patient with moderate risk staging/CRC?
T3, N0, V1, R0
Which drug is used in chemotherapy for treated CRC?
5FU given with Folinic acid (given for 3 months)
What is CEA?
carcinoembryonic antigen
What is CEA use as in CRC?
It is a marker used to determine if there is a recurrence of the disease, however it can also be raised in smokers or people with alcoholic liver disease
If patients have isolated metastatic disease within the liver, what is the first-line treatment choice?
Surgery - 40% chance of resection of the liver mets, as long as there is a single site and low volume disease
What side effects do patients have to live with, even with cure of the cancer?
Bowel: 1. Diarrhoea 2. Urgency 3. Frequency 4. Incontinence (anterior bowel disorder) Bladder: 1. Frequency 2. Incontinence Sexual: 1. Impotence 2. Vaginal stenosis Infertility: 1. Premature menopause Psychological: 1. Living with a stoma 2. Sexual 3. Anxiety Financial 1. Loss of job 2. Loss of earnings
