Colorectal Cancer Flashcards
What are the risk factors for colorectal carcinoma?
Diet- High in fats and low in fibre
IBD- ulcerative colitis
Genetics- HNPCC, FAP, Gardner’s
How common is colorectal cancer?
2nd most common cancer in the uk
What is the most common histologic type of colorectal carcinoma?
Adenocarcinoma- 90-95%
Mucous/signet ring
Others include: Squamous cell Carcinoid GIST Primary malignant lymphoma
Where are colorectal carcinomas most commonly located?
Rectum- 40%
Sigmoid colon-20%
Caecum - 6%
Remaining colon- 34%
How does colorectal cancer spread?
Local invasion
Lymphatic
Venous
Transcoelomic
Where does colorectal cancer tend to spread?
Hepatic metastases most common
What tests might be used as a screening test for colorectal cancer?
Faecal occult blood
What is the occult presentation of colorectal cancer?
Iron deficiency anaemia in colorectal cancer located in the right side of colon and caecum
What is the dukes staging system for CRC?
A- invades mucosa and sub mucosa
B- penetrates muscularis mucosa
C- lymph nodes
D- metastases
Investigations for CRC?
Rectal exam - detects 75%! Rigid sigmoidoscopy - up to 25cm Flexible sigmoidoscopy Colonoscopy Double contrast barium enema CT - staging Carcinoembryonic antigen - monitoring
When is surgery used in CRC?
In early stage - usually curative, standard choice due to unsuspected nodal mets
In advanced disease- resection of liver metastases, resection of local reoccurrence
Palliative - surgery/colonic stunting for obstructive lesions
When is radiotherapy used in CRC?
In rectal carcinomas as less risk to other organs
For local recurrence or treatment of metastatic bone disease
When is chemotherapy used in CRC
Adjuvant for high risk cases, dukes c+
Oxaliplatin, irinotecan, 5FU
What is the prognosis of the different dukes stages of CRC
A- 80% five year survival
B- 50%
C- 15-40%
D- 5%
