1b// GI Cancers Flashcards
What is the definition of cancer?
A disease caused by an uncontrolled division of abnormal cells in a part of the body
What does it mean a primary cancer?
Arising directly from the cells in an organ
What does it mean a secondary/ metastasis cancer?
Spread from another organ, directly or by other means (blood or lymph)
What are the three types of tissues/ cells that can be affected in the GI tract by cancer?
epithelial cells
neuroendocrine cells
connective tissue
Which epithelial cells in the GI tract become cancer and what type of cancer do they become?
Which neuroendocrine cells in the GI tract become cancer and what type of cancer do they become?
Which connective tissues in the GI tract become cancer and what type of cancer do they become?
What are the most common cancers of the GI tract?
adenocarcinoma
neuroendocrine tumours (NETs)
Where can GI cancers form/ NETs?
liver
oesophagus
gastric
pancreas
colon
NETs can be formed anywhere in the GI tract
Who does colorectal cancer generally affect?
patients older than 50 y/o
What are the forms of colorectal cancer?
sporadic
familial
hereditary syndrome
What is sporadic colorectal cancer?
Absence of family history, older population, isolated lesion
What is familial colorectal cancer?
Family history, higher risk if index case is young (<50years) and the relative
is close (1st degree)
What is hereditary syndrome 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 of colorectal cancer?
adenocarcinoma
Describe the mutation of colorectal cancer.
What are the risk factors for colorectal cancer?
What does the presentation of colorectal cancer depend on?
location of cancer
Where can colorectal cancers appear?
2⁄3 in descending colon and rectum
1⁄2 in sigmoid colon and rectum (i.e. within reach of flexible
sigmoidoscopy)
- caecal and right sided cancer
- left sided and sigmoid carcinoma
- rectal carcinoma
- bowel obstruction (late)
What is the clinical presentation of caecal and right sided cancer?
Iron deficiency anaemia (most common)
Change of bowel habit (diarrhoea)
Distal ileum obstruction (late)
Palpable mass (late)
What is the clinical presentation of left sided and sigmoid carcinoma?
PR bleeding, mucus
Thin stool (late)
What is the clinical presentation of rectal carcinoma?
PR bleeding, mucus
Tenesmus
Anal, perineal, sacral pain (late)
What is the clinical presentation of local invasion (late) colorectal cancer?
Bladder symptoms
Female genital tract symptoms
What is the clinical presentation of metastasis colorectal cancer (late)?
Liver (hepatic pain, jaundice)
Lung (cough)
Regional lymph nodes
Peritoneum
- Sister Marie Joseph nodule
What are the signs of primary colorectal cancer?
Abdominal mass
DRE: most <12cm dentate and reached by examining finger
Rigid sigmoidoscopy
Abdominal tenderness and distension – large bowel obstruction
What are the signs of metastasis and complications of colorectal cancer?
Hepatomegaly (mets)
Monophonic wheeze
Bone pain
What are the type of investigations for colorectal cancer?
Faecal occult blood
Blood Tests
Colonoscopy
CT colonoscopy/ colonography
MRI pelvis
CT chest/ abdo/ pelvis
What is tenesmus?
Want to go to loo, but can’t
What foecal occult blood investigations would be done for colorectal cancer?
Guaiac test (Hemoccult) – based on pseudoperoxidase activity of haematin
- Sensitivity of 40-80%; Specificity of 98%
- Dietary restrictions – avoid red meat, melons, horse-radish, vitamin C &
NSAIDs for 3 days before test
FIT (Faecal Immunochemical Test) - detects minute amounts of blood in faeces (faecal occult blood).
What blood tests would be done for colorectal cancer investigations?
FBC: anaemia, haematinics – low ferritin
Tumour markers: CEA which is useful for monitoring
* NOT diagnostic tool
What are colonoscopies useful for in colorectal cancer?
Can visualize lesions < 5mm
Small polyps can be removed
- Reduced cancer incidence
Are colonoscopies sedated?
yes usually
Why are CT colonoscopies/ colonography useful for colorectal cancer?
Can visualize lesions > 5mm
No need for sedation
Less invasive, better tolerated
If a lesion is identified with a colonography, what do you do for a diagnosis?
If lesions identified patient needs colonoscopy for diagnosis
Why do you perform a MRI pelvis for colorectal cancer, and what are the benefits of MRI pelvis?
For rectal cancer
Depth of invasion, mesorectal lymph node involvement
No bowel prep or sedation required
Help choose between preoperative chemoradiotherapy or straight to
surgery
Why is there CT of chest/ abdo/ pelvis in colorectal cancer?
staging prior to treatment
How is colon cancer primarily managed?
by surgery
How do you manage colorectal cancer?
stent (if not fit for surgery)/ radiotherapy/ chemotherapy/ surgery
What is the difference between right and left handed obstructing colon carcinoma?
right and transverse colon is safer because it has a good blood supply so good healing
left sided obstruction is more complicated
How do you treat a right and transverse colon obstructing colon carcinoma?
resection and primary anastomosis
How do you manage a left sided obstructing colon carcinoma?
Hartmann’s procedure
- Proximal end colostomy (LIF)
- +/- Reversal in 6 months
Primary anastomosis
- Intraoperative bowel lavage with primary anastomosis (10% leak)
- Defunctioning ileostomy
Palliative stent (if not fit for surgery e.g., too old)
Describe the colonic arterial supply and resection.