Colorectal Tumors Flashcards
4th most common cancer affecting men and women in the world
Large bowel cancer
Patients more at risk of large bowel cancer
Older patient
Risk factors colorectal ca
Diet - red meat, processed meat, alcohol
Obesity
Smoking
Lack of physical activity
Inflammatory bowel disease (CD, UC)
Inherited genetic disorders (familial adenomatous polyposis , hereditary non polyposis colon ca)
Old age
Male sex
Percentage of people with colorectal cancer that have little to no genetic risk
75-95%
Type of Cell involved in colorectal ca
Epithelial cells lining of colon or rectum
Cell mutated in colorectal ca
Intestinal crypt stem cell
Most commonly mutated gene in colorectal cancer
APC gene
What is function of APC gene and how does it lead to cancer
Produce APC protein which prevents accumulation of B catenin
Without APC , B catenin accumulates and bind DNA and activated transcription of protooncogenes
Name of mutation that affect b catenin itself and block its own breakdown
CTNNB1
Other genes mutated in colorectal ca
P53 - tumor suppressor
BAX - tumor suppressor
Mismatch repair deficient tumors (MMR proteins)
Clinical features of colorectal ca
Worsening constipation
Blood in stool
Decreased stool thickness
Loss of appetite
Loss of weight
Nausea
Vomiting
No symptoms - 50%
Rectal bleeding
Anemia
Change in bowel habit
Abdominal pain
Tiredness
Lethargy - anemia
Investigations
Blood tests
Stool tests
Proctoscopy
Rigid/flexible sigmoidoscopy
Colonoscopy
CT colonography
CT scan
MRI scan
Ultrasound
PET scan
Radiology xray
Endoscopic
Microscopy
Histopathology
Most common form of colon cancer
Adenocarcinoma 95-98%
Rare types of colon cancer
Lymphoma
Adenosquamous ca
Squamous cell ca
How to stage colorectal cancer
Local invasion
Degree of lymph node involvement
Distant metastasis
