1. SCREENING FOR
COLORECTAL CANCER
Presenter - Dr Tadesse H. (Colorectal surgery fellow)
Moderator - Professor Berhanu Kotisso
(Professor of General and Colorectal Surgery)
AAU,CHS April 5,2024 GC
4. Introduction
Third most common cancer worldwide(10%)
Second leading cause of cancer-related deaths worldwide.
It predominantly affects older individuals
Several lifestyle factors contribute to the development of colorectal
cancer
Diagnosed at advanced stages when treatment options are limited
5. Colorectal cancer statistics, 2023
CA A Cancer J Clinicians, Volume: 73, Issue: 3, Pages: 233-254, First published: 01 March 2023, DOI: (10.3322/caac.21772)
Risk factors
Screening
Treatment
46%
57%
long-term trends in colorectal cancer incidence and mortality
6. SCREENING RATIONALE
Natural history of colorectal cancer and colon polyps
Benefits of screening
Harms associated with screening
Cost and cost-effectiveness
• DOI: 10.1053/gast.1997.v112.agast970594
GASTROENTEROLOGY 1997;112:594 –642
7. Rationale of screening…
Removal of adenomatous
polyp
76-90% reduction in the
incidence of colorectal
cancer
• DOI: 10.1053/gast.1997.v112.agast970
594
9. Harms and associated with screening
One might consider three sources of harm:
• Harms attributable to the process of screening per se
• Harms directly attributable to the test
• Harms of managing individuals with a positive screening result
These harms can be psychological harms or physical harms
Colonoscopy risks-screening
• Cardiopulmonary risks-<1%
• Perforation 0.03-0.07%
• Bleeding after polypectomy- 0.5 %
• Death attributable to a colonoscopy- 1 in 15,000
Gastroenterology. 2016 May;150(5):1052-5. Epub 2016 Mar 24.
12. ASSESSING RISK FOR COLORECTAL CANCER
A "no"
response to all
of these
questions
generally
indicates
Average risk.
Have you ever had CRC or an adenomatous
polyp?
Have any biological family members had
CRC or a documented advanced polyp?
Do you have biological family members with
any of the known genetic syndromes that can
cause CRC?
Do you have inflammatory bowel disease
(ulcerative colitis or Crohn’s disease)?
Did you receive abdominal radiation for
childhood cancer?
JAMA. 2011;306(2):172.
13. Table - High-risk groups for the development of colorectal cancer
High risk group Lifetime risk of
colorectal cancer
Hereditary colorectal cancer >50%
Familial colorectal cancer 20-90%
Individual with a personal history of colorectal
cancer or colorectal adenoma
15-20%
Individual with other diseases (e.g., ulcerative colitis) 10-20%
18. SOCIAL FACTORS AND HEALTH EQUITY
• Several factors have been shown to contribute to disparities
• Disproportionate rates of exposure to risk factors
• Historical social injustices
• Barriers to access to screening and other preventive services
The USPSTF encouraged the development of delivery services to ensure
equitable access to high-quality care from screening through treatment.
19. SOCIAL FACTORS AND HEALTH EQUITY…
AVAILABILITYAND USE OF COLORECTAL CANCER
SCREENING
• Guidelines
• Policies
• Population based
• Opportunistic
• Programmed implementation
• Organization
• Target age range
• Screening strategy
• Quality assurance
• Participation
IARC (2019). Colorectal cancer screening. IARC Handb
Cancer Prev. 17:1–300. Available from:
http://publications.iarc.fr/573.
22. AGE TO INITIATE SCREENING…
Guideline by societies Minimum age of
recommendation
(Average risk)
US Preventive Services Task Force (USPSTF) Grade B- 45-year,
Grade A – 50 years
The American College of Gastroenterology (ACG) 2021
guidelines
45 years
American Cancer Society (ACS) 45 years
Canadian Task Force on Preventive Health Care
(CTFPHC)
European Council
The American Academy of Family Physicians (AAFP)
The American College of Physicians (ACP)
50 years
JAMA. 2021;325(19):1965.
Am J Gastroenterol. 2021;116(3):458.
23. AGE TO INITIATE SCREENING…
50 years
• Canadian Task Force on Preventive Health Care
(CTFPHC)
• European Council
• The American Academy of Family Physicians
(AAFP)
• The American College of Physicians (ACP)
• US Preventive Services Task Force (USPSTF)-
Grade A Recommendation
45 years
• US Preventive Services Task Force (USPSTF)- Grade B
Recommendation
• The American College of Gastroenterology (ACG) 2021
guidelines
• American Cancer Society (ACS)
Starting at age 45 when compared to starting at 50
4-8% decrease in the number of new CRCs
8-11% decrease in CRC deaths
12-17 % increase in the number of colonoscopies needed
JAMA. 2021;325(19):1965.
25. DISCONTINUING SCREENING
Individualized
based on shared
decision-making
• Risk for colorectal cancer (CRC)
• Prior screening history
• Personal values
• Patient's comorbid conditions
• Life expectancy
JAMA. 2022;327(12):1171.
Never been screened, one-time screening
Colonoscopy to age 83
years
Sigmoidoscopy to 84
years
Fecal immunochemistry
testing to 86 years
75 years for average-risk patients, life expectancy
is 10 years or greater.
Life expectancy is less than 10 years
26. CHOOSING SCREENING TEST
Advising patients about screening
Preferred tests
Other tests used
Tests that are less effective or lack sufficient evidence on
effectiveness
Resource-limited setting
Ann Intern Med. 2019;171(9):643
27. Advising patients about screening
After determining whether a patient is at average risk for CRC
• We use motivational interviewing
• Shared decision-making techniques to assess patient preferences
• Recommend screening
28. Barriers to screening
Fear and
embarrassment
Unpleasant of
tests
Transportation
Lack of
insurance/cost
Physician
recommendation
Lack of
symptoms
Health Education
29. Test options for colorectal cancer screening
Stool-based tests
Fecal immunochemical test (FIT)
every year
Guaiac-based fecal occult blood
test (gFOBT) every year
Multi-targeted stool DNA test with
fecal immunochemical testing (MT-
sDNA) every 3 years
Visual (structural) exams of
the colon and rectum
Colonoscopy every 10
years
CT colonography (virtual
colonoscopy) every 5 years
Sigmoidoscopy every 5
years
32. Tests that are less effective
DRE
Office-based gFOBT after DRE
Barium enema
CEA
33. Resource-limited settings
In a basic setting
• Highly sensitive gFOBT is recommended every one (preferred) to two years
• FIT as a suggested alternative every one (preferred) to two years.
In a limited setting with more resources
• Highly sensitive gFOBT yearly or sigmoidoscopy every five years
• FIT yearly or sigmoidoscopy every 10 years plus yearly FIT (preferred) or
yearly FOBT.
DOI: 10.1200/JGO.18.00213
An ASCO guideline, (Stratified recommendation) for average-risk patients aged
50 to 75 according to the availability of clinical resources in the patient’s setting.
35. If a stool-based test is positive, a second stool
test should not be done.
• Performing the colonoscopy promptly and within three
months is advised.
When a screening stool test is positive,
and colonoscopy is both complete and
without abnormality, patients should
return to the routine screening schedule.
FOLLOW-UP OF ABNORMAL RESULTS
37. PAMJ - Clinical Medicine. 2021;5:37.
[doi: 10.11604/pamjcm20.21.5.37.26398]
Results: the mean age of the participants was 43.5 years (SD=15.67) with a range of 15-84 years; 60.5% were
male participants. The vast majority (95.1%) of colonoscopy indications were judged as appropriate.
Evaluation for rectal bleeding (31.7%) and suspected colorectal cancer (15.2%) were the commonest
indication for colonoscopy. However, screening colonoscopy for asymptomatic subjects
was almost non-existent. The most common colonoscopy findings were hemorrhoidal diseases
(28.5%) and gross mass lesions (14.9%). The overall diagnostic yield was 74.1% being highest among patients
presenting with lower gastrointestinal bleeding and bowel habit changes. About 58.3% of bowel preparations
in this study were optimum but an excellent preparation was extremely low (13.3%).
Conclusion: our study revealed that colonoscopy procedures for symptomatic patients were performed for
appropriate indications for most of the cases. However, screening colonoscopy was extremely
low. The relatively high rate of abnormalities and malignant lesions in this finding calls for a
national strategy for early colonoscopy screening of high-risk populations.
39. Reference
Gordon and Nivatvongs’ Principles and Practice of Surgery for the Colon, Rectum, and Anus
4th ed.
Scott R. Steele, Tracy L. Hull, Neil Hyman, Justin A. Maykel, Thomas E. Read, Charles B.
Whitlow
IARC (2019). Colorectal cancer screening. IARC Handb Cancer Prev. 17:1–300. Available from:
http://publications.iarc.fr/573.
UpToDate
Common
Lethal
Preventable
Involve all of the colon with preferably ….
Lifetime risk of colorectal cancer is 5 %
A major risk factor for colon cancer is Failure to get screened
According to (CDC), only two-thirds of eligible patients in the United States have been screened for colorectal carcinoma.
primary prevention strategies such as adopting a healthy lifestyle, avoiding risk factors, and practicing early detection through screening.
Trends in colorectal cancer incidence (1975–2019) and mortality (1930–2020) rates by sex, United States. Because of changes in the International Classification of Diseases coding for mortality, numerator information has changed over time. Incidence rates exclude appendiceal cancer, are age‐adjusted to the 2000 US standard population, and adjusted for reporting delays. Source: Incidence: Surveillance, Epidemiology, and End Results Program, 2022; Mortality: National Center for Health Statistics, 2022.
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The various ways of screening for colorectal carcinoma, all have cost-effectiveness ratios comparable to those of other generally accepted screening tests.10,11
It is important to note that once the screening results are positive, a complete investigation of the entire colon and rectum is mandated to identify colorectal polyps or carcinomas.
At asymptomatic state
Screening for Sporadic CRC
Screening guidelines for CRC directly relate to the time that it takes for a polyp to become an adenocarcinoma and at what age does the risk of developing CRC increase to the point where screening is more efficacious than harmful. If an average-risk patient has a low risk of CRC based on finding no polyps on their initial screening colonoscopy, then another intervention is likely not needed for 10 years. However, when patients are found to have polyps, particularly when there are multiple lesions or high-risk lesions, the patient has proven that for genetic or environmental reasons, they are at increased risk and their screening interval should be shorter.
Most of the polyps don’t develop carcinoma
Fewer than 10% of all adenomas become cancerous. However, more than 95% of colorectal cancer develop from adenomas
Examining stage distribution and 5-year survival by stage highlights the potential benefits associated with early detection and treatment.
Cost, discomfort and consecutive colonoscopy
level of risk impacts screening and follow-up recommendations.
Have any biological family members had CRC or a documented advanced polyp?
were they first-degree relatives (parent, sibling, or child), and at what age was the cancer or polyp first diagnosed?
The USPSTF encouraged the development of delivery services to ensure equitable access to high-quality care from screening through treatment, particularly for people from groups that experience disproportionate incidence, late-stage diagnosis, and death from CRC.
Europe
Some guidelines recommend stopping screening for CRC when the patient's life expectancy is less than 10 years [34].
We continue to screen for CRC through age 75 years for average-risk patients, as long as their life expectancy is 10 years or greater.
For older adults who have never been screened, results of a modeling study suggest that one-time screening appears to be cost-effective up to an age that varies depending on the patient’s life expectancy, comorbidities, and the test used for screening [35].
colonoscopy was cost-effective to age 83 years, sigmoidoscopy to 84 years, and fecal immunochemistry testing (FIT) to 86 years.
Noninvasive screening tests such as FIT and multitarget stool deoxyribonucleic acid testing (MT-sDNA) can be mailed directly to patients to be completed in the comfort of their homes.
Health extension providers are our opportunities
Carcinoembryonic antigen (CEA), a tumor marker that may be used for surveillance of patients with CRC, is not a useful screening test for CRC.
Colonoscopy quality
High definition colonoscopy
Careful exam of the entire colon
At least 6 min( usually clos to 10 min)
> 95 % cecal intubation
Adenoma detection rate(ADR)
Lower limit- 20 % for women,30 % for men
An ASCO guideline, developed by a multinational panel, stratifies recommended and alternative CRC screening tests for average-risk patients aged 50 to 75 according to the availability of clinical resources in the patient’s setting [48,49].
We therefore do not recommend screening patients if there is no access to colonoscopy if the test is positive.
If a stool-based test is positive, a second stool test should not be done instead of a follow-up colonoscopy, because a subsequent negative stool test result does not mean that the first result was a false positive.
Colorectal cancer screening can save lives, but only if people get tested!
