1. 27th Annual Winter CME Conference
February 8-11, 2017
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2. Colorectal Cancer Screening - a review and update
Sean E. McGarr D.O., FACG
Therapeutic Endoscopist
Director Gastrointestinal
Oncology Services, HACCC
MaineGeneral Gastroenterology
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3. Outline The goal of this talk: What are colon polyps?
Colorectal cancer (CRC) statistics
Screening guidelines
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4. GI tract
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6. Colonic polyps Protuberance into the normally flat colonic mucosa
Asymptomatic
Classified as
sessile
pedunculated
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7. Colonic polyps Hyperplastic polyps Adenomatous polyps common (rectum)
indistinguishable from adenomatous polyps
Adenomatous polyps
nearly all colorectal cancers arise from adenomas
only minority of adenomas progress to cancer (1 in 20 or less)
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8. Serrated polyps
The term serrated has slightly different features seen with the microscope. Both types need to be removed from your colon.
These types of polyps are not cancer, but are precancerous and therefore, you have some increased risk of subsequently developing cancer of the colon.
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10. Distribution of colon polyps
15%
10%
25%
50%
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11. Genetics of colon cancer
Colon cancer arises as a series of histopathologic & molecular changes:
Normal epithelial cells
Small adenomatous polyp
Large adenomatous polyp
Colorectal carcinoma
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1 Janne, NEJM 2000;342:1960
2 Fearon, Cell1990;61:759

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16. CRC epidemiology U.S. statistics in 2012
143,460 new cases
51,690 deaths
3rd/2nd most frequent diagnosed cancer in men and women
3rd/2nd leading cause of cancer death
Maine statistics in 2012
750 new cases
260 deaths (preliminary)
74 cases with 21 deaths MGMC in 2011
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17. For average risk individual
6% lifetime risk for being diagnosed with colorectal cancer
2.5% chance of dying from it
Results in premature death
Average loss: 13 years of life
>90% of cases occur in patients > 50
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19. Rational for screening
CRC does not develop overnight
More than 80% of CRC arise from adenomatous polyp
Polyps < 1cm is size
<1% risk from cancer
Polyps > 1cm in size
10% risk for developing into cancer in 10 years
Removal of polyps
70 to 90% risk reduction for CRC
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20. Defining CRC risk groups
Average risk group
>50 years of age
No personal of family history of CRC
No history of inflammatory bowel disease
80% of CRC arises in this group
High risk group
Personal and/or family history of CRC or polyp
Long standing colitis
Genetic predisposition
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21. Screening guidelines for the average risk group
Begin screening at age 50
Asymptomatic
Annual Fecal Occult Blood Test (FOBT)
15-43% reduction in CRC mortality
3 consecutive stool samples annually
Can detect up to 92% of all cancers when repeated annually
Dietary restrictions
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22. Limitations of FOBT Sensitivity limitations Specificity limitations
Relatively insensitive detecting polyps compared to CRC
Specificity limitations
False positive rate
Necessitates additional procedures
Endoscopy
Stool DNA
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23. *Colonoscopy is the screening method that MaineHealth providers recommend for their patients.
Other Types of Screening Include:
Flexible Sigmoidoscopy
Fecal Occult Blood Test (FOBT) Physician’s Guidelines
Fecal DNA
Fecal Immunoassay (FIT test)
Double Contrast Barium Enema
CT Colonography (Virtual Colonoscopy)
Digital Rectal Exam is NOT considered beneficial in CRC screening and not recommended as a preferred screening choice
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25. Colonoscopy Benefits Most sensitive and specific screening tool
Definitive treatment
If polyps detected then proceed with polypectomy
Almost eliminates risk for progression to CRC
Lowers the risk for CRC development
Lowers the risk for CRC related death
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26. Colonoscopy Disadvantages “My rule of thousands”
Complications (perforation, bleeding, polypectomy syndrome, infection)
Overall routine risk 0.35%
Polypectomy risk 2.3%
Lifetime risk of CRC 6%
High costs
Bowel preparation
Public health capacity limitations
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27. Virtual Colonoscopy Reconstructed spiral CT images Non-invasive
No sedation
Allows visualization of the entire colon
Still require preparation
Uncomfortable VC CC
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28. Roberta Rietti: CT Colonography Master Thesis - YouTube
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29. Fecal immunochemical test (FIT)
The fecal immunochemical test (FIT) is a screening test for colon cancer
It tests for blood in the stool
FIT only detects human blood from the lower intestines
Medicines and food do not interfere with the test, so it tends to be more accurate and have fewer false positive results than other tests
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30. FIT vs. FOBT
Monoclonal/poly Ab to detect globin proteins which do not survive passage from the UGI
FIT true-positive
CRC 87% vs. 54%
Polyps >10mm 45% vs. 23%
No need to modify diet or ASA
Cost $75 vs $5
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31. After considering public comments and consulting with appropriate organizations, the Centers for Medicare & Medicaid Services (CMS) has determined that the evidence is sufficient to cover CologuardTM –
A multitarget stool DNA test – A colorectal cancer screening test for asymptomatic, average risk beneficiaries, aged 50 to 85 years. Therefore, Medicare Part B will cover the CologuardTM test once every three years for beneficiaries who meet all of the following criteria:
Age 50 to 85 years
Asymptomatic (no signs or symptoms of colorectal disease including but not limited to lower gastrointestinal pain, blood in stool, positive guaiac fecal occult blood test or fecal immunochemical test).
At average risk of developing colorectal cancer (no personal history of adenomatous polyps, colorectal cancer, or inflammatory bowel disease, including Crohn’s Disease and ulcerative colitis; no family history of colorectal cancers or adenomatous polyps, familial adenomatous polyposis, or hereditary nonpolyposis colorectal cancer).
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34. Surveillance colonoscopy
CRC screening
FOBT
Sigmoidoscopy
Colonoscopy
Virtual colon
Fecal markers
Colonoscopy
Surveillance colonoscopy
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36. High risk group 1 to 2 first-degree relatives with CRC or adenomas
1st degree relative with CRC <40 years of age
Hereditary CRC syndromes
Initial screening 40 or 10 years less
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37. High risk surveillance
National polyp study
15 to 25% probability of missed polyp
High risk for advanced polyp at follow up
3 or more polyps at initial colonoscopy
>60 years of age and family history CRC
Repeat exam at 3-5 years
Low risk for advanced polyp at follow up
Repeat exam at 5 years
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38. High risk surveillance
After complete removal of adenoma with invasive cancer (malignant polyp)
Repeat examination in 3 to 6 months
Repeat at 1 year
Extend to 3 – 5 years
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