1. Colon polyps Peter Stanich, MD
Assistant Professor; Division of Gastroenterology, Hepatology & Nutrition
Director; Section of Intestinal Neoplasia and Hereditary Polyposis

2. Learning objectives:
Identify the characteristics of neoplastic disease of the colon, rectum, and anus incorporating the causes, epidemiology, clinical features, diagnosis, and management concepts
Define colon polyp. Describe the pathology and significance of: 1) tubular and tubulovillous adenoma; 2) villous adenoma; 3) hyperplastic polyp; 4) hamartomatous polyp.
List the types of colon polyps.
Describe the relationship between colon polyps and colon cancer.
Identify current screening recommendations for colon cancer.
Describe tests for screening and diagnosing colon polyps and colon cancer.
List the most common signs and symptoms of colon cancer. Explain why colon carcinoma should be excluded when there is onset of altered bowel habit in patients of age at risk.
Describe the epidemiology of adenocarcinoma of the colon.
List the risk factors for the development of colon cancer.
Explain staging of colon cancer and survival implications.

3. Neoplastic disease of the colon, rectum & anus
Colon or rectal polyp – Protuberance from the flat colonic mucosa - or - raised lesion seen at endoscopy. Much more to come…
Colorectal cancer (CRC) – Adenocarcinoma. Focus of second articulate module in series…
Definitions:
Dysplasia - Abnormality of growth and differentiation of cells
Neoplasia – Atypical proliferation of cell growth

4. Colon polyps
Asymptomatic, unusual but if large can cause microscopic blood loss or rarely small amount of rectal bleeding if distal location
There are multiple different histologic types of polyps

5. Colon polyps Colon polyp Hyperplastic Neoplastic * Most common
Non-neoplastic
Hamartoma
Inflammatory pseudopolyps
- Not classic polyps
Adenoma
Serrated
Submucosal
- Not classic polyps

6. Adenomatous colon polyps
2/3 of all colon polyps are adenomas
By definition, they are all dysplastic
- Even the small tubular adenomas that don’t have it mentioned on path reports

7. Adenomatous colon polyps
Classifications:
Endoscopic appearance
Sessile: Base is attached to the wall
Pedunculated: Mucosal stalk from polyp to wall
Pathology
Tubular (80% of adenomas)
Tubulovillous (mixed)
Villous (finger-like glands, higher risk)

8. Adenomatous colon polyps
Classifications:
Advanced adenomas:
High-grade dysplasia
> 1 cm size
Villous histology (ie. villous or tubulovillous)
These are higher risk for progression to CRC and development of future CRC
*3 or more adenomas at a single colonoscopy is also a risk factor

9. Adenomatous colon polyps
Risk factors for development of adenomas:
Age
Male sex
Obesity
African Americans are at higher risk for large adenomas
Family history
Forsberg et al. Prevalence of colonic neoplasia and advanced lesions in the normal population. Scandinavian Journal of Gastro

10. Adenomatous colon polyps
Colonoscopy and adenoma removal (polypectomy) reduces mortality from colorectal cancer (CRC)
Zauber et al. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. NEJM 2/23/12.

11. Adenoma to Carcinoma sequence
Colon Carcinogenesis and the Effects of Chemopreventive Agents.
Adenoma to Carcinoma sequence
Jänne PA, Mayer RJ. N Engl J Med 2000;342:
Figure 1. Colon Carcinogenesis. Colon cancers result from a series of pathologic changes that transform normal colonic epithelium into invasive carcinoma. Specific SOMATIC genetic events in tumor suppressor genes, shown by vertical arrows, accompany this multistep process.
The APC gene mutation will be discussed later in the context of germline mutation giving rise to familial adenomatous polyposis. P53 germline mutations lead to Li Fraumeni which has a multitude of young onset cancers associated with it. These are both tumor suppressor genes and thus loss of function leads to unchecked cell growth. KRAS is an oncogene so mutation leads to gain of function.
< 5% of polyps progress, takes 7-10 years

12. Colon cancer screening
Terminology review:
Screening: no personal history of cancer or precancerous lesions and no clinical signs
Surveillance: History of CRC or polyps
Diagnostic: Symptoms concerning for CRC

13. Colon cancer screening
Multiple societies have proposed them, but most/all are similar
Colonoscopy is preferred as diagnostic and PREVENTATIVE, other options discussed later only diagnostic

14. Colon cancer screening
Credit: Colonversation Colonoscopy animation
Colonoscopy movie plays in 24 seconds
in a separate browser
“Colonversation Colonoscopy animation” — Medical Illustration Copyright 2009 Nucleus Medical Art. All rights reserved.

15. Colon cancer screening
Average risk:
Colonoscopy at age 50
If no polyps, repeat in 10 years
Increased risk due to family history
Colonoscopy at age 40 or 10 years younger than earliest affected first degree relative
If no polyps, repeat every 5 years
Discuss what qualifies as family history: 1 FDR with CRC or advanced adenoma at < 60, 2 FDR with CRC or advanced adenoma at any age
FDR = first degree relative ie parent, sibling, child

16. Colon cancer screening options
Preferred (for all): Colonoscopy
Other options (only in average risk):
Every 5 years: Flexible sigmoidoscopy ± fecal occult blood test (FOBT), CT colonography or barium enema
Annual: Fecal immunochemical test (FIT), FOBT (out of favor)
Future of stool testing may be Fecal DNA (promising recent study)

17. Serrated colon polyps
Referred to as sessile serrated adenomas or sessile serrated polyps
Also includes the less common traditional serrated adenoma
Despite names, they are distinct from adenomas
Progress to CRC through a microsatellite instability pathway with BRAF mutation (likely similar risk to adenomas but still to be determined)
They are more common in the proximal colon and are often flat and difficult to spot
BRAF is an oncogene, thus similar to a somatic pathway of the germline Lynch syndrome

18. Serrated colon polyps
They can be very hard to see!

19. Serrated colon polyps
Malignant potential of these lesions is only recent realized
Thought to account for majority of interval cancers (which occur more commonly in right colon and likely to show microsatellite instability)

20. Hyperplastic colon polyps
Non-neoplastic, but have a serrated morphology
Most common non-neoplastic polyp
No known risk of progression to cancer
Very common in rectosigmoid, usually a small sample are biopsied to confirm or “optical biopsied” but not all need to be removed

21. Hamartomatous colon polyps
Hamartoma = Disorganized growths of native cells in native tissues
Can be difficult to distinguish pathologically, but juvenile polyps and Peutz-Jegher polyps are in this category
Can be sporadic if only a few, if multiple associated with specific hereditary syndromes (Peutz Jeghers, Juvenile polyposis, PTEN hamartoma tumor syndrome/Cowden syndrome) with high multi-organ cancer risks
Have increased risk of CRC, due to rarity can be difficult to quantify

22. Inflammatory pseudopolyps
Islands of intact colon mucosa that form secondary to bowel wall inflammation and regeneration
Most often seen with ulcerative colitis
Do not need to be resected and do not have malignant potential per se, but can complicate surveillance in IBD patients

23. Submucosal polyps/lesions
They arise from beneath the epithelium to create protuberance into lumen but the epithelium is normal
Although may technically fit the broadest definition of a polyp, most would consider a lesion or mass
Examples include lipoma (pictured), leiomyoma, carcinoid tumors
Surface biopsies unrevealing,
often need deeper biopsy for
diagnosis
These often arise from the MM, submucosa or MP
Copyright © 2011 John Wiley & Sons, Inc. All rights reserved. From

24. Key Points
Adenomas are most common neoplastic polyp and removal of them reduces the incidence and mortality of colorectal cancer
Sessile serrated adenomas/polyps are suspected as a cause of right-sided colon cancers
Colonoscopy preferred screening method as both preventative and diagnostic, but other methods exist and can be utilized if needed
Average risk CRC screening begins at age 50

25. Colon Polyps Quiz

26. Thank you
with questions/comments:

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