1B GI cancers Flashcards
What are GI tract squamous cell cancers called?
Squamous cell carcinoma (SCC)
What are GI tract glandular epithelium cell cancers called?
Adenocarcinoma
What are GI tract enteroendocrine cell cancers called?
Neuroendocrine tumours (NETs)
What are GI tract interstitial cells of Cajal cancers called?
Gastrointestinal stromal tumours (GISTs)
What are GI tract smooth muscle cell cancers called?
Leiomyoma/leiomyosarcoma
What are GI tract adipose tissue cell cancers called?
Liposarcoma
Which age group does colorectal cancer affect most?
> 50 years (more than 90% of cases)
What is lifetime risk for colorectal cancer in men and women?
- 1 in 10 for men
- 1 in 14 for women
What are the three forms of colorectal cancer?
- Sporadic
- Familial
- Hereditary
What are the criteria of sporadic colorectal cancer?
- Absence of family history
- Older pop
- Isolated lesion
What are the criteria for familial colorectal cancer?
- Family history
- Higher risk if index case is young (<50 years) and the relative is close (1st degree)
What are the criteria for hereditary colorectal cancer?
- Family history
- Younger age of onset
- Specific gene defects
- e.g. Familial adenomatous polyposis (FAP), hereditary nonpolyposis colorectal cancer (HNPCC or Lynch syndrome)
What is the histopathology (type of cancer) for all colorectalcancers?
Adenocarcinoma
Describe the progression of colorectal cancer
What does the progression of colorectal cancer mean for people who have 1 polyp?
- They get repeat colonoscopies to check for new polyps developing
- It’s straightforward to endoscopically take polyps away before they become cancer- prophylactic endoscopic polyp/adenoma resections
What does aspirin do?
Protects against the development of the progression of polyps in colorectal cancer
What are the three types of risk factors for colorectal cancer?
- Past history
- Family history
- Diet/environmental
What should past history look like for patients with colorectal cancer?
- Colorectal cancer
- Adenoma (polyps), ulcerative colitis, radiotherapy-treated patients
What should family history include for patients with colorectal cancer?
- 1st degree relative <55 years
- Relatives with identified genetic predisposition e.g.
- FAP
- HNPCC
- Peutz-Jegher’s syndrome (increases risk of polyp development and cancer)
What are dietary/environmental risk factors for patients with colorectal cancer?
- Smoking
- Obesity
- Socioeconomic status
- Carcinogenic foods
What are the locations of colorectal cancer?
- 2/3 in descending colon (left colon) and rectum
- 1/2 in sigmoid colon and rectum (i.e. within reach of flexible sigmoidoscopy)
How do caecal and right sided colorectal cancer patients present?
- Iron deficiency anaemia (most common)
- Change of bowel habit (diarrhoea)
- Distal ileum obstruction (late sign)
- Palpable mass (late sign)
How do left sided and sigmoid carcinoma colorectal cancer patients present?
- PR (rectal) bleeding, mucus
- Thin stool (late sign)
How do rectal carcinoma colorectal cancer patients present?
- PR bleeding, mucus
- Tenesmus- the feeling of needing to open bowels but nothing comes out when you try
- Anal, perineal, sacral pain (late sign)
What is a late sign of bowel cancer?
Bowel obstruction
What kind of signs show local invasion of colorectal cancer?
These are late signs
- Bladder symptoms
- Female genital tract symptoms
Where can colorectal cancer metastasise to (late sign) and how can these present?
- Liver (hepatic pain, jaundice)
- Lung (cough)
- Regional lymph nodes
- Peritoneum (Sister Mary Joseph nodule is metastasis in umbilicus- image below)
What are the signs of primary colorectal cancer and how do we find these signs?
- Abdominal mass
- Abdominal tenderness and distension- large bowel obstruction
- DRE: most <12cm from dentate line and reached by examining finger
- Rigid sigmoidoscopy
What are the signs of metastasis and complications?
- Hepatomegaly
- Monophonic wheeze
- Bone pain
What investigations are done for colorectal cancer?
- Faecal occult blood
- Blood tests
- Colonoscopy
- CT colonoscopy/colonography
- MRI pelvis
- CT chest/abdo/pelvis
What are the two types of faecal occult blood?
-
Guaiac test (Haemoccult)- based on pseudoperoxidase activity of haematin
- 40-80% sensitivity and 98% specificity
- Dietary restrictions- avoid red meat, melons, horse-radish, vitamin C and NSAIDs for 3 days before test
- FIT (faecal immunochemical test)- detects minute amounts of blood in faeces (faeces occult blood)
What blood tests are done for colorectal cancer?
- FBC: anaemia, haematinics- low ferritin
- Tumour markers: CEA (carcinoembryonic antigen) which is useful for monitoring evidence of recurrence but not as a diagnostic tool
What does a colonoscopy do?
- Visualise lesions <5mm
- Small polyps can be removed- reduced cancer incidence
How can small polyps be removed using colonoscopy?
Pedunculated polyp (with a stalk) → we put wire around it and use heat to cut it and to close wound to prevent bleeding
Usually performed under sedation
How does a CT colonoscopy compare with normal colonoscopy?
- Can visualise lesions >5mm
- No need for sedation
- Less invasive, better tolerated
- If lesions identified then patient needs colonoscopy for diagnosis
When is MRI pelvis performed?
If you have a tumour that you think is relatively advanced
What is looked at in MRI pelvis?
- Depth of invasion, mesorectal lymph node involvement- to see whether we can do an R0 resection (take all of cancer out with good margin)
- No bowel prep or sedation required
- Help choose between preop chemoradiotherapy to reduce tumour size or go straight to surgery
Why is CT chest/abdo/pelvis done for colorectal cancer?
Staging prior to treatment to exclude liver or lung metastases
What is the primary management for colorectal cancer?
Surgery
What can you do to give yourself time to plan surgery for colorectal cancer?
Put a stent in or use radio or chemo
What do you do with a right and transverse colon obstructing carcinoma?
- Usually they don’t obstruct because there’s more leeway for carcinoma to expand
- If it is obstructing, we can resect and join up straight away with primary anastomosis because blood supply is good so it won’t leak
Why do you have to be more careful with a left sided obstruction?
The blood supply on left colon isn’t as good
We can put in a palliative stent
What is a Hartmann’s procedure?
Remove the tumour but then instead of joining proximal bowel and rectum, we bring proximal bowel up to skin and do a colostomy (leaving a stoma)- called a proximal end colostomy (LIF)
We can reverse in 6 months if patient is fine
What’s the difference between a stoma on the left or right side of a patient?
- left side means colostomy (large bowel)
- right side means ileostomy (small bowel)
If patient has left sided obstruction, we can do a primary anastomosis (joining up proximal bowel and rectum). Why is this not the safest?
- We would do an intraoperative bowel lavage with primary anastomosis
- However there’s a 10% chance of leak because the blood supply isn’t the best
What are the important right sided arteries?
- Ileocolic
- Right colic
- Middle colic
What are the important left sided arteries?
- Left colic
- When we get to pelvis, sigmoid arteries are important
What is a right hemicolectomy?
Remove right colon then anastomose terminal ileum to transverse colon
What is an extended right hemicolectomy?
Take around 2/3 of large bowel out- right colon and part of transverse
Then do ileocolic anastomosis
What is a left hemicolectomy?
Resect left colon then anastomose remaining colon parts