Colorectal cancer screening

1. COLORECTAL CANCER SCREENING
Updated guidelines
Dr. PHẠM THIÊN TÁNH
Department: GI-ENDOSCOPY

2. OUTLINE
• WHY
• WHO
• HOW
• WHEN

3. WHY SCREEN PTS FOR CRC?

4. FACTS ABOUT COLORECTAL CANCER IN VIETNAM

6. Where does CRC come from?
Most CRC develop over years from
adenomatous or serrated polyps.
• Polyps are very common and
increase with age, but very few
progress to cancer.
• Polyps that are larger or have
dysplasia or villous histology ->
higher cancer risk
• Estimate of polyp dwell time from a
< 1 cm adenomatous polyp to an
invasive cancer is at least 10 years.

7. The value of early detection thru
screening
Detection and removal of
clinically significant polyps
Incidence
Mortality
Detection and treatment of
early-stage CRC
Mortality

8. Who are the candidates for screening?
Need to know patient’s:
• Risk level
• Screening and surveillance history
• Age
• Comorbidities
• Preferences

9. Risk stratification
• Average Risk
• No signs or symptoms of CRC.
• None of the risk factors below.
• Increased Risk
• Family history of CRC or adenomas in a first-degree relative or CRC in two
second-degree relatives.
• Personal history of adenomas, certain serrated polyps, or CRC.
• High Risk
• Inflammatory bowel disease: chronic ulcerative colitis or Crohn’s colitis.
• Highest Risk
• Confirmed or suspected genetic syndromes (FAP, HNPCC).

10. Screening for Colorectal Cancer:
AVERAGE RISK

11. Ages to Screen
• The ACS recommends people at average risk of colorectal
cancer start regular screening at age 45.
• People who are in good health and with a life expectancy
of more than 10 years should continue regular colorectal
cancer screening through the age of 75.
• For people ages 76 through 85 -> person’s preferences,
life expectancy, overall health, and prior screening history.
• People over 85:

12. Screening for Colorectal Cancer: 2021 US Preventive Services Task Force Recommendation Statement

14. HOW
• We recommend colonoscopy and FIT as the primary
screening modalities for CRC screening.
Strong recommendation; low-quality evidence
• We suggest consideration of the following screening tests for
individuals unable or unwilling to undergo colonoscopy or FIT:
flexible sigmoidoscopy, multitarget stool DNA test, CT
colonography or colon capsule.
Conditional recommendation; very low-quality evidence
ACG Guidelines 2021

15. SCREENING INTERVALS
Stool-Based Tests
Highly sensitive gFOBT every year
FIT every year
FIT-DNA every 3 years
Visualization Tests
Colonoscopy 10 years
CT colonography every 5 years
Flex Sig every 5-10 years
Flex Sig with FIT Flex sig every 10 years + FIT every year

16. COLONOSCOPY
PROS:
• It allows for not only the
detection of early-stage cancers
but also the detection and
removal of polyps.
• Long-term reduction in CRC
incidence 31%–71% and CRC
mortality 65%–88% from
observational studies.
• Infrequent repeat interval (q10
years) possible

17. COLONOSCOPY
CONS:
• Operator dependent
• Requires bowel preparation and sedation
• Risk of complications 4–8 in 10,000

18. COLONOSCOPY
SOLUTIONS:
We recommend that all endoscopists performing
screening colonoscopy should measure their individual
cecal intubation rates (CIRs), adenoma detection rates
(ADRs), and withdrawal times (WTs)
• CIR ≥ 95%
• ADR ≥ 25%
• WT ≥ 6 mins
ACG Guidelines 2021

19. FECAL OCCULT BLOOD TEST

20. gFOBT
FOOD/ DRUGS AVOID
Red meat, like beef, lamb, and pork, and
other foods like broccoli, turnips,
horseradish, and cauliflower
3 DAYS
Vitamin C supplements, juices, fruit that
will give you more than 250 mg of
vitamin C per day
3-7 DAYS
Iodine supplements, colchicine 3-7 DAYS
NSAIDS, Aspirin 7 DAYS

21. FECAL IMMUNOCHEMICAL TEST
YOUR TITLE PLACE HERE
• 79% sensitivity and 94% specificity for CRC
Pros Cons
Noninvasive Positive results require
colonoscopy
No risk of complications Needs to be repeated annually
Can be done at home Low sensitivity for advanced
adenomas
Programmatic screening possible Does not detect serrated lesions

22. • FDA-approved, combines a FIT with a stool DNA test (Assay for mutant
KRAS, methylated BMP3, methylated NDRG4)
• 92% sensitivity and 87% specificity for CRC
• Long-term reduction in CRC incidence and mortality is unknown
• Higher single-test cancer and polyp detection than FIT alone
• Lower specificity than FIT alone, resulting in more false-positive results
and more diagnostic colonoscopy.
• Insufficient evidence on the appropriate follow-up of positive findings
after a negative colonoscopy.
• May lead to overly intense surveillance due to concerns over the DNA
component.
MULTITARGET STOOL DNA TEST (FIT-DNA)

23. CT colonography
• Requires bowel preparation.
• Sensitive for polyps ≥ 6mm and cancer, poor sensitivity for flat
lesions and sessile serrated lesions.
• Positive results require colonoscopy
• Follow-up may be required for extracolonic findings
• Limited availability of trained radiologists.

24. Screening for Colorectal Cancer:
INCREASED RISK
• If patient has either:
• CRC or advanced polyp in 01
first-degree relative (FDR)
diagnosed at age < 60 OR
• CRC or advanced polyp in 02 FDR
with CRC at any age
• If patient has either:
• CRC or advanced polyp in 01 FDR
at age > 60
• Two second-degree relatives
with CRC
Colonoscopy every 5 years
starting at age 40, or 10 years
before the youngest affected
relative, whichever comes first.
Begin screening at age 40 or 10
years before the youngest
affected relative and then
resuming average-risk screening

25. • Patients with inflammatory bowel disease (IBD): chronic
ulcerative colitis or Crohn’s colitis
Refer to a center with experience in IBD surveillance and
management
Screening for Colorectal Cancer:
HIGH RISK

26. Screening for Colorectal Cancer:
HIGHEST RISK
Patients with family history of or suspected Hereditary
NonPolyposis Colon Cancer (HNPCC), Familial
Adenomatous Polyposis (FAP), or other syndrome:
• Refer for genetic counseling and testing.
• Obtaining a complete family history is critical.
• Testing may begin in late teens and 20s, so family
history must be known early.

27. Hereditary Non-polyposis Colorectal Cancer
(HNPCC)
3-2-1 rule to identify patients with Lynch Syndrome
(HNPCC) – meeting Amsterdam Criteria
• 3 closely related relatives with CRC or Lynch-related
cancers*
• 2 generations involved (at least)
• 1 person < age 50 at time of developing the cancer

28. Familial Adenomatous Polyposis (FAP)
• Multiple adenomas
• Polyps not present at birth
but appear during 2nd and
3rd decades
• Risk of colorectal cancer
~100% by age 40
• Autosomal dominant

29. TAKE HOME MESSAGE
• Provide Colonoscopy or FIT for average risk patients (no
signs or symptoms, no sig risks) starting from 45 yrs of
age and ending in 85 yrs of age. Screening intervals:
Colonoscopy: 10 yrs, FIT: every year
• Increased risk patients: starting at age 40, or 10 yrs
before the youngest affected relative.
• High or highest risk patients -> specialist referral
• Surveillance of patients with adenomas at prior
Colonoscopy -> specialist referral

30. References
• CDC- Colorectal Cancer Screening Continuing Education
• ACG Clinical Guidelines: Colorectal Cancer Screening 2021
• Screening for Colorectal Cancer: 2021 US Preventive Services Task
Force Recommendation Statement
• Colorectal cancer screening for average‐risk adults: 2018
guideline update from the American Cancer Society
• Screening and Surveillance for the Early Detection of Colorectal Cancer and
Adenomatous Polyps, 2008: A Joint Guideline from the American Cancer
Society, the US Multi-Society Task Force on Colorectal Cancer, and the
American College of Radiology