An update on bowel cancerscreening and polyp surveillance

Dr Pran Yoganathan

Gastroenterologist

Does Bowel Cancer Screening work?

Does Bowel Cancer Screening work?

• Yes

• Unfortunately bowel cancer is not rare in Australia.

• It currently kills around 80 Australians/week.

• But, if detected early, the number of people dying from bowel cancer can be reduced.

• If caught early, up to 90% of cases can be successfully treated

Should every asymptomatic 50 year (and older) have a colonoscopy?

After 50 years of age, should you have a colonoscopy 3 to 5 yearly?

Is colonoscopy being overdone?

Is Medicare sustainable?

Principles for population screening (WHO)

• The cost of screening (including diagnosis and treatment of patients diagnosed) should be economically balanced in relation to possible expenditure on medical care as a whole

iFOBT vs. Colonoscopy

• iFOBT is the most economically viable test, not colonoscopy.

• Colonoscopy, at around $3000 per service vs. $30 FOBT kit

• Colonoscopy is inappropriate screening tool in asymptomatic people

• iFOBT• 85% sensitivity/90% specificity

• NPV-98%

• Colonoscopy• Sensitivity 95%

Success of any screening program

• Only 9% of the population would comply with colonoscopy for screening

• iFOBT current NBCSP participation is 35%• Predicated to rise to 60-80% by 2040

• Success of a screening program = Accuracy x Participation

Colonoscopy in Sydney's Eastern suburbs

• 30 times higher than the area with the lowest rate and double the national average.

• People in poorer areas are not having them done. • Lack of awareness about symptoms of disease• Low participation rates in NBCSP• Shortage of services in some regions• High private insurance in certain areas means, there is financial incentive

for proceduralist

Overtreatment is costing $30 billion/yr.

• Implementation of possible screening programs will be influenced by consideration of the equal distribution of limited resources across the whole community for maximum benefit.

• Resources allocated to a screening program will lower resources available for other health needs.

“Practice variation"

• Rates of diagnostic colonoscopy per cancer detected across one Australian state over a five-year period we found a more than tenfold variation in rates between suburbs.

• This was even after adjusting for differences in patient age, chronic disease and risk factors such as diet and smoking.

• Cancer survival rates were no better for those suburbs with very high rates of colonoscopy than those with low rates

We need adherence to guidelines.

NHMRC Guidelines

• “ Average risk, Australians aged 50 and over should be screenedonce every 2 years for bowel cancer”

NBCSP Participation

Important point from this talk

1. The ideal screening strategy for the family physician

2. Polyp surveillance, an update on the new guidelines

The ideal screening strategy for the family physician

How to assess an asymptomatic patients CRC risk

History

• Age

• Family history

• Hx of adenomas

• History of IBD

• Smoking

• Poor diet and/or lifestyle

Physical examination

Risk categories

1. Average risk

2. Slightly above average risk

3. Moderately increased risk

4. High risk

Case 2

• 50yr old male

• Checkup visit

• Fit & healthy

• No GI symptoms

• No meds

• No FHx

What’s the best diagnostic tool?

• Reassurance

• FOBT

• CT Colonography

• Colonoscopy

Age as a risk factor

Case 2

• 50yr old male

• Checkup visit

• Fit & healthy

• No GI symptoms

• No meds

• No FHx of bowel cancer / polyps

• Average risk

• Risk of bowel cancer in the next 5yrs • 1/300

Screening recommendation

• Average risk population

• FOBT, 2 yearly from the age of 50

• No requirement for a colonoscopy

Patient insistent on colonoscopy?

• Should get one for reassurance, risk stratification and then appropriate counseling from the Endoscopist

Case 3

• Asymptomatic

• No GI symptoms

• No previous history of adenomas, CRC or IBD

• FHx of CRC

• Father died aged 62 yrs of age from metastatic bowel cancer

What’s the best diagnostic tool?

• Reassurance

• FOBT

• CT Colonography

• Colonoscopy

Slightly above average risk

• 1st degree relative with CRC > age 55

Or

• 2nd degree relative with CRC > age 55

Age as a risk factor

Slightly above average risk

• 1st degree relative with CRC > age 55

• Risk is doubled

• 1/150 (over the next 5yrs)

• 2nd degree relative with CRC > age 55

• Risk is increased 1.5 fold

• 1/200 (over the next 5yrs)

Screening recommendation

• In slightly above average risk population

• FOBT, 2 yearly from the age of 50

• No requirement for a colonoscopy

Case 4

• 46yr old male

• Fit & healthy

• No GI symptoms

• Mother died of CRC at age 54

What’s the best diagnostic tool?

• Reassurance

• FOBT

• CT Colonography

• Colonoscopy

Moderate risk

• 1 first-degree relative with CRC < 55yrs

• 2 first-degree relatives, with CRC at any age

• 1 first and 1 second-degree relatives with CRC at any age

***Same side of the family*****

Moderate risk

• Relative risk in these two situations is increased 3 to 6 fold

Age as a risk factor

Moderate Risk

• Over the next 5yrs after the age of 50

• Risk in this group is 1/50

Screening recommendation

• In the moderate risk population, FOBT vs. Colonoscopy

• The at risk relative should be referred for a colonoscopy at 5-yearly intervals, starting at age 50

• Or 10 years younger than the age of the earliest diagnosis of cancer in the family

Case 4

• 46yr old male

• Fit & healthy

• No GI symptoms

• Mother died of CRC at age 54

• Start screening at 44yrs of age

• Colonoscopy Not FOBT

Case 5

• 34yr old male

• Fit & healthy

• Family history of CRC, father 48, brother 29, paternal grandfather 62, paternal uncle 44, Asymptomatic

What’s the best diagnostic tool?

• Reassurance

• FOBT

• CT Colonography

• Colonoscopy

High risk

• Relative risk of ~4–20

• Bowel cancer will occur in 1/10

• Refer to Gastroenterologist to plan appropriate surveillance and genetic screening

• Familial cancer syndromes, FAP, HNPCC, MUTHY, Serrated polyposis syndrome

Ideal screening strategy & Role of GPs

1. GPs play a key role in ensuring that program participants progress through the screening pathway.

2. Encourage those who are sent a screening test and for whom the test is clinically relevant, to participate

3. Positive result refer them for colonoscopy to someone who has an interest in bowel cancer screening

4. Manage individuals in accordance with the NHMRC Guidelines.

5. Inform individuals at “average risk” that the NHMRC Guidelines recommend screening at least once every two years from the age of 50.

NHMRC guidelines for polyp surveillance

Case 6

Dear Family Physician

Thank you for sending this 72 year old man who had a few polyps 10 years ago and has had 3 normal colonoscopies since. There is no family history of bowel cancer. I would like to see him again in 3 years for another colonoscopy.

Signed,

Your local Gastroenterologist/Surgeon.

”All polyps needs a surveillance colonoscopy every 3 years”

Polyp to Carcinoma sequence10 to 15 years

”All polyps needs a surveillance colonoscopy every 3 years”

• Incorrect

• Wasteful

• This concept does not adhere to evidence or guidelines

Adenomas

• Patients who have adenomatous polyp removed at colonoscopy• Above-average risk for further adenomas and bowel cancer

• When compared to the general population

• If no adenoma on subsequent surveillance (and no family history): • Then consider stopping endoscopic surveillance

• Suggest stool based screening

Low risk adenomas

• Number• < 2 adenomas on colonoscopy

• Histopathology• Tubular adenomas

• Size• Smaller than 10mm

Low risk adenomas: Surveillance

• The 1st surveillance colonoscopy should be performed at 5 years

• If that colonoscopy is normal, then individual is average risk for CRC

• Options for subsequent surveillance• FOBT every 2 years (Australia/NHMRC guidelines)

• 10 yearly colonoscopy (USA guidelines)

High risk adenomas

• Number• 3 or more adenomas on

colonoscopy

• Histopathology• Tubulovillous or Villous

adenomas

• High grade dysplasia

• Size• Larger than 10mm

High risk adenomas

• 3 yearly colonoscopy

• Stop after a normal colonoscopy and revert to stool based screening • Till the “stopping rule” applies

Distal hyperplastic polyps

• Should be distinguished from adenomas

• Left sided hyperplastic polyps confer no increased risk of bowel cancer

• Require no endoscopic follow-up

• 2 yearly FOBT

Questions?