2. CRC Screening

Question 1

What are the 2 broad categories of Health Screening?

Answer 1

1. Universal

2. Targeted

Question 2

What two factors will preclude the introduction of a screening programme?

Answer 2

No if there is no treatment

No if high rate of false negatives/positives (e.g. PSA screening)

Question 3

List the Wilson and Junger Screening Criteria

Answer 3

1. Important health problem?
2. Accepted treatment available?
3. Facilities for diagnosis and treatment should be available?
4. Recognised latent or early symptomatic stage?
5. Suitable test/exam?
6. Acceptable to population?
7. Natural history of disease understood?
8. Agreed policy on who to treat?
9. Cost of case-finding should be acceptable?
10. Case finding a continuous process

Question 4

What is the name given to the criteria for screening efficacy?

Answer 4

Wilson and Junger Screening Criteria

Question 5

What are the risk factors for Colorectal Cancer?

Answer 5

Age
20% of >50yo will have polyps

Family history of CR/polyps

Active Inflammatory Bowel Disease
o Specific ‘at risk’ conditions (5%)
o Lynch Syndrome
o Familial Adenomatous Polyposis (FAP)

Lifestyle factors (weaker than in smoking)
o	Obesity
o	Smoking (slight evidence of prevention)

Question 6

What are the 2 broad categories of CRC Screening Tools?

Answer 6

1. Stool Testing

2. Structural Assessment

Question 7

What are the two Stool Tests used in CRC screening, and what does it detect?

Answer 7

FOB and FIT

Fecal Occult Blood Test and Fecal Immunochemical Test

Question 8

What are the relative advantages of FIT v FOB testing?

Answer 8

FIT
•	Single sample (versus 3)
•	Specific to Human
•	No Diet Restrictions
•	Higher efficacy.

Question 9

What are the 3 types of structural Colorectal Assessment?

Answer 9

• Sigmoidoscopy
• Colonoscopy (US/Canada use for screening)
• CT colonography (used left often)

Question 10

Compare the efficacy of Colonoscopy versus FIT testing for CRC screening.

Answer 10

Colonoscopy is highly effective in screening and reducing mortality for CRC/Polyps
In average risk population
o 67% reduction in CRC
o 65% reduction in death
Polypectomy can prevent 80% of colorectal cancers

Better than Stool testing but lower uptake by population
Uptake 34% for FIT versus 24% for colonoscopy
Also cultural issues within different population groups/races

Question 11

What are the potential advantage of CRC Screening?

Answer 11

Lifetime reduction in the incidence of colorectal cancer by early detection and removal of polyps
Lifetime reduction in mortality (36%)
One of the most clinically effective and cost effective public health interventions

Question 12

Who is the target group for the National Bowel Screening Programme?

Answer 12

Target Group = 55-75yo

Question 13

What is the uptake rate, the positive testing rate and the number of cancers?

Answer 13

• 700,000 invited
• 400,00 participate in 2 years cycle
• 50-60% FIT test uptake = 200,000
• 5% positive FIT test =10,000
• 1,000 cancers.

Question 14

What are the 2 broad categories of Polyps that may be found on colonoscopy?

Answer 14

1. Pendunculated Polyps (Narrow Elongated Stalk)

2. Sessile Polyps (No Stalk)

Question 15

How are Sessile Polyps Removed?

Answer 15

Can perform a submucosal injection polypectomy
o Injection of saline to elevate submucosa
o Snare can remove raised polyp

Question 16

In terms of numbers of adenomatous polyps, what is considered low, intermediate and high risk for CRC?

Answer 16

1-2x <1cm or ≥3x ≥1cm = High