Colonic polyp: Difference between revisions

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In [[medicine]], '''colonic polyps''' are "discrete tissue masses that protrude into the lumen of the [[colon]]. These [[polyp]]s are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base."<ref>{{MeSH}}</ref>
In [[medicine]], '''colonic polyps''' are "discrete tissue masses that protrude into the lumen of the [[colon]]. These [[polyp]]s are connected to the wall of the colon either by a stalk, pedunculus, or by a broad base."<ref>{{MeSH}}</ref> Colonic polyps may become [[colorectal cancer]].


==Classification==
==Classification==
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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> Similar numbers have been reported by other studies.<ref name="pmid18941093">{{cite journal |author=Pickhardt PJ, Hassan C, Laghi A, ''et al'' |title=Clinical management of small (6- to 9-mm) polyps detected at screening CT colonography: a cost-effectiveness analysis |journal=AJR Am J Roentgenol |volume=191 |issue=5 |pages=1509–16 |year=2008 |month=November |pmid=18941093 |doi=10.2214/AJR.08.1010 |url=http://www.ajronline.org/cgi/pmidlookup?view=long&pmid=18941093 |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>
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> Similar numbers have been reported by other studies.<ref name="pmid18941093">{{cite journal |author=Pickhardt PJ, Hassan C, Laghi A, ''et al'' |title=Clinical management of small (6- to 9-mm) polyps detected at screening CT colonography: a cost-effectiveness analysis |journal=AJR Am J Roentgenol |volume=191 |issue=5 |pages=1509–16 |year=2008 |month=November |pmid=18941093 |doi=10.2214/AJR.08.1010 |url=http://www.ajronline.org/cgi/pmidlookup?view=long&pmid=18941093 |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==
A [[clinical practice guideline]] jointly written by the [[American Cancer Society]] and other groups recommends one of:<ref>Levin, B., Lieberman, D. A., McFarland, B., Smith, R. A., Brooks, D., Andrews, K. S., et al. (2008). [http://caonline.amcancersoc.org/cgi/content/full/CA.2007.0018v1 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}}.</ref>
* Flexible sigmoidoscopy every 5 years
* Barium enema every 5 years
* [[Computed tomographic colonography|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:<ref name="pmid16697750">{{cite journal |author=Winawer SJ, Zauber AG, Fletcher RH, ''et al'' |title=Guidelines for colonoscopy surveillance after polypectomy: a consensus update by the US Multi-Society Task Force on Colorectal Cancer and the American Cancer Society |journal=Gastroenterology |volume=130 |issue=6 |pages=1872–85 |year=2006 |month=May |pmid=16697750 |doi=10.1053/j.gastro.2006.03.012 |url=http://www.gastrojournal.org/article/S0016-5085(06)00561-0/fulltext |issn=}}</ref>
* 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:<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>
* 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==
==References==
<references/>
<references/>

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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] Colonic polyps may become colorectal cancer.

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] The rate of progression to invasive cancer among polyps of at least 10 mm size is about 1% per year.[5]

High risk colonic polyps are defined as either:[6]

  • 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] Similar numbers have been reported by other studies.[7] The risk of recurrence of future high risk histology is also correlated with size.[8]

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. Stryker SJ, Wolff BG, Culp CE, Libbe SD, Ilstrup DM, MacCarty RL (November 1987). "Natural history of untreated colonic polyps". Gastroenterology 93 (5): 1009–13. PMID 3653628[e]
  6. 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.
  7. Pickhardt PJ, Hassan C, Laghi A, et al (November 2008). "Clinical management of small (6- to 9-mm) polyps detected at screening CT colonography: a cost-effectiveness analysis". AJR Am J Roentgenol 191 (5): 1509–16. DOI:10.2214/AJR.08.1010. PMID 18941093. Research Blogging.
  8. 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]