Colonic polyp: Difference between revisions

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imported>Robert Badgett
imported>Robert Badgett
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==Prognosis==
==Prognosis==
{| class="wikitable" align=right
{| class="wikitable" align=right
|+ Risk depends on polyp size (adapted from Table 2 in Butterly<ref name="pmid16527698">{{cite journal |author=Butterly LF, Chase MP, Pohl H, Fiarman GS |title=Prevalence of clinically important histology in small adenomas |journal=Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association |volume=4 |issue=3 |pages=343–8 |year=2006 |month=March |pmid=16527698 |doi=10.1016/j.cgh.2005.12.021 |url= |issn=}}</ref>)
|+ Risk depends on polyp size (adapted from Table 2 in Butterly<ref name="pmid16527698">{{cite journal |author=Butterly LF, Chase MP, Pohl H, Fiarman GS |title=Prevalence of clinically important histology in small adenomas |journal=Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association |volume=4 |issue=3 |pages=343–8 |year=2006 |month=March |pmid=16527698 |doi=10.1016/j.cgh.2005.12.021 |url= |issn=}}</ref> and Johnson<ref name="pmid18799557">{{cite journal |author=Johnson CD, Chen MH, Toledano AY, ''et al'' |title=Accuracy of CT colonography for detection of large adenomas and cancers |journal=The New England journal of medicine |volume=359 |issue=12 |pages=1207–17 |year=2008 |month=September |pmid=18799557 |doi=10.1056/NEJMoa0800996 |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=18799557&promo=ONFLNS19 |issn=}}</ref>)
! Polyp size !! Cancer<br>% ([[confidence interval]])!! Villous histology or<br>high-grade dysplasia<br>% ([[confidence interval]])!! Total<br>% ([[confidence interval]])
! Polyp size !! Cancer<br>% ([[confidence interval]])!! Villous histology or<br>high-grade dysplasia<br>% ([[confidence interval]])!! Total<br>% ([[confidence interval]])
|-
|-
| <u><</u> 4 mm || align=center|0 (0–.36)||align=center| 1.68 (.87–2.49) ||align=center| 1.68 (.87–2.49)
| <u><</u> 4 mm || align=center|0 (0–.36)||align=center| 1.68 (.87–2.49) ||align=center| 1.68 (.87–2.49)
|-
|-
| 5–10 mm ||align=center| 0.87% (.26–1.48)||align=center| 9.23 (7.32–11.14) ||align=center| 10.10 (8.11–12.08)
| 5–9 mm ||align=center| 0.87% (.26–1.48)||align=center| 9.23 (7.32–11.14) ||align=center| 10.10 (8.11–12.08)
|-
| <u>></u> 10 mm ||align=center| 5%||align=center| &nbsp; ||align=center| &nbsp;
|}
|}


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* villous histology or high-grade dysplasia
* villous histology or high-grade dysplasia


The risk of [[dysplasia]] depends on the size of the polyp (see table).<ref name="pmid16527698">{{cite journal |author=Butterly LF, Chase MP, Pohl H, Fiarman GS |title=Prevalence of clinically important histology in small adenomas |journal=Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association |volume=4 |issue=3 |pages=343–8 |year=2006 |month=March |pmid=16527698 |doi=10.1016/j.cgh.2005.12.021 |url= |issn=}}</ref>
The risk of current [[dysplasia]] depends on the size of the polyp (see table).<ref name="pmid16527698">{{cite journal |author=Butterly LF, Chase MP, Pohl H, Fiarman GS |title=Prevalence of clinically important histology in small adenomas |journal=Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association |volume=4 |issue=3 |pages=343–8 |year=2006 |month=March |pmid=16527698 |doi=10.1016/j.cgh.2005.12.021 |url= |issn=}}</ref> The risk of recurrence of future high risk histology is also correlated with size.<ref name="pmid18347350">{{cite journal |author=Laiyemo AO, Murphy G, Albert PS, ''et al'' |title=Postpolypectomy colonoscopy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years |journal=Ann. Intern. Med. |volume=148 |issue=6 |pages=419–26 |year=2008 |month=March |pmid=18347350 |doi= |url=http://www.annals.org/cgi/content/full/148/6/419 |issn=}}</ref>


==Screening==
==Screening==

Revision as of 10:12, 27 October 2008

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Colonic polyp
Colonic polyp.jpg

Colonic polyp
ICD-9 V12.72
OMIM 175100
MeSH D003111

In medicine, colonic polyps are "discrete tissue masses that protrude into the lumen of the colon. These polyps are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base."[1]

Classification

In a study of 2531 volunteers 50 years of age or older:[2]

  • 1629 (64%) had no polyps
  • 902 (36%) had polyps
    • 512 (57% of the 902) had polyps with the largest being less than 5 mm in size
    • 258 (29% of the 902) had 392 polyps with the largest being 5 mm - 9 mm in size
      • 246 (63% of the 392 polyps) were adenomatous
      • 146 (27% of the 392 polyps) were non-adenomatous such as hyperplastic polyps and lipomas
    • 132 (15% of the 902) had 155 polyps with the largest being 10 mm or larger in size
      • 121 (78% of the 155 polyps) were adenomatous
      • 7 (5% of the 155 polyps) were carcinomas
      • 27 (17% of the 155 polyps) were non-adenomatous

Hyperplastic polpys

Adenomatous polyps

Adenomatous colonic polyps are common and are present in 25% of men and 15% of women undergoing screening colonoscopy.[3]

Tubular adenomas
Tubulovillous adenomas
Villous adenomas

Prognosis

Risk depends on polyp size (adapted from Table 2 in Butterly[4] and Johnson[2])
Polyp size Cancer
% (confidence interval)
Villous histology or
high-grade dysplasia
% (confidence interval)
Total
% (confidence interval)
< 4 mm 0 (0–.36) 1.68 (.87–2.49) 1.68 (.87–2.49)
5–9 mm 0.87% (.26–1.48) 9.23 (7.32–11.14) 10.10 (8.11–12.08)
> 10 mm 5%    

Adenomatous colonic polyps may progress to colorectal cancer; however, less than 10% do so.[3]

High risk colonic polyps are defined as either:[5]

  • 3 or more synchronous adenomas
  • adenomas ≥1 cm in diameter
  • villous histology or high-grade dysplasia

The risk of current dysplasia depends on the size of the polyp (see table).[4] The risk of recurrence of future high risk histology is also correlated with size.[6]

Screening

A clinical practice guideline jointly written by the American Cancer Society and other groups recommends one of:[7]

  • Flexible sigmoidoscopy every 5 years
  • Barium enema every 5 years
  • Virtual colonography (a noninvasive test based on computed tomography) every 5 years
  • Colonoscopy every 10 years

When polyps are found, a clinical practice guideline jointly written by the American Cancer Society and other groups states:[5]

  • High risk polyps are 1) 3 or more synchronous adenomas, 2) adenomas ≥1 cm in diameter, or 3) villous histology or high-grade dysplasia.
  • High risk polyps should have follow-up colonoscopy in 3 years
  • Low risk polyps should have repeat colonoscopy in 5 to 10 years
  • If no adenomas are found, follow-up evaluation should be at 10 years

A validation of these guidelines found:[6]

  • High risk adenomas - 9% of an advanced adenoma at 4 years of follow-up.
  • Low risk adenomas - 5% of an advanced adenoma at 4 years of follow-up.

Thus, the criteria for high risk identified 60% of the subsequent high risk recurrences.

References

  1. Anonymous (2024), Colonic polyp (English). Medical Subject Headings. U.S. National Library of Medicine.
  2. 2.0 2.1 Johnson CD, Chen MH, Toledano AY, et al (September 2008). "Accuracy of CT colonography for detection of large adenomas and cancers". The New England journal of medicine 359 (12): 1207–17. DOI:10.1056/NEJMoa0800996. PMID 18799557. Research Blogging.
  3. 3.0 3.1 Levine JS, Ahnen DJ (December 2006). "Clinical practice. Adenomatous polyps of the colon". The New England journal of medicine 355 (24): 2551–7. DOI:10.1056/NEJMcp063038. PMID 17167138. Research Blogging.
  4. 4.0 4.1 Butterly LF, Chase MP, Pohl H, Fiarman GS (March 2006). "Prevalence of clinically important histology in small adenomas". Clinical gastroenterology and hepatology : the official clinical practice journal of the American Gastroenterological Association 4 (3): 343–8. DOI:10.1016/j.cgh.2005.12.021. PMID 16527698. Research Blogging.
  5. 5.0 5.1 Winawer SJ, Zauber AG, Fletcher RH, et al (May 2006). "Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society". Gastroenterology 130 (6): 1872–85. DOI:10.1053/j.gastro.2006.03.012. PMID 16697750. Research Blogging.
  6. 6.0 6.1 Laiyemo AO, Murphy G, Albert PS, et al (March 2008). "Postpolypectomy colonoscopy surveillance guidelines: predictive accuracy for advanced adenoma at 4 years". Ann. Intern. Med. 148 (6): 419–26. PMID 18347350[e]
  7. Levin, B., Lieberman, D. A., McFarland, B., Smith, R. A., Brooks, D., Andrews, K. S., et al. (2008). 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. CA Cancer J Clin, CA.2007.0018. DOI:10.3322/CA.2007.0018.