colorectal cancer and screening Flashcards
1
Q
What are the genereal risk factors of colorectal cancer?
A
- Most (85%) are sporadic with no familial/genetic influence
- 10% have a familial risk
- Inheritable conditions: HNPCC (5%), FAP (<1%), other CRC syndromes
- 1% associated with underlying Inflammatory Bowel Disease (IBD)
2
Q
What are the risk factors of sporadic cases?
A
- Age
- Male gender
- Previous adenoma/CRC
- Environmental influences:
- Diet (low in fibre, low in fruit & veg, low in calcium, high in red meat, high in alcohol,)
- Obesity
- Lack of exercise
- Smoking
- Diabetes Mellitus
3
Q
Describe colorectal polyps
A
- The majority of colorectal cancers arise from pre-existing polyps
- protuberant growths
- variety of histological types
- epithelial or mesenchymal
- benign or malignant
4
Q
What is the presentation of colorectal cancer?
A
- Rectal bleeding
- Altered bowel opening- diarrhoea
(Each symptom on its own, investigate if age >60yrs; combined symptoms, investigate age >40yrs) - Iron Deficiency Anaemia men of any age and non-menstruating women (more likely to have right sided colonic malignancy)
- Palpable rectal or right lower abdominal mass
- Acute colonic obstruction if stenosing tumour
- Systemic symptoms of malignancy: Weight loss, Anorexia
5
Q
What are the modalities for screening colorectal cancer?
A
- Faecal occult blood test (FOBT)
- Faecal immunochemical test (FIT)
- Flexible Sigmoidoscopy
- Colonoscopy
- CT Colonography
6
Q
What is the population screening for colorectal cancer?
A
- Age 50-74 years
- FOBT every 2 years
- If FOBT positive-> colonoscopy
- Stage shift in detected cancers (48% Dukes A v 11% in non-screened)
- ~15%reduction in the relative risk of colorectal cancer mortality
7
Q
Who are the high risk groups that are screened for colorectal cancer?
A
- Heritable conditions
- FAP (familial adenomatous polyposis)
- HNPCC (hereditary non-polyposis colorectal cancer)
- Inflammatory bowel disease
- Familial risk
- Previous adenomas/Colorectal cancer
