Editing Colonoscopy (section)

===Colon cancer screening===
Colonoscopy is one of the colorectal cancer screening tests available to people in the US who are 45 years of age and older. The other screening tests include [[flexible sigmoidoscopy]], [[double-contrast barium enema]], [[virtual colonoscopy|computed tomographic (CT) colonography]] (virtual colonoscopy), [[stool guaiac test|guaiac-based fecal occult blood test]] (gFOBT), [[fecal immunochemical test]] (FIT), and [[multitarget stool DNA screening test]] (Cologuard).<ref>{{cite web | title=Colorectal Cancer Prevention and Early Detection | url=http://www.cancer.org/acs/groups/cid/documents/webcontent/003170-pdf.pdf | pages=16–24 | publisher=[[American Cancer Society]] | date=5 February 2015 | access-date=25 December 2015 | archive-date=16 November 2015 | archive-url=https://web.archive.org/web/20151116102751/http://www.cancer.org/acs/groups/cid/documents/webcontent/003170-pdf.pdf | url-status=live }}</ref>

Subsequent rescreenings are then scheduled based on the initial results found, with a five- or ten-year recall being common for colonoscopies that produce normal results.<ref>{{cite journal | vauthors = Rex DK, Bond JH, Winawer S, Levin TR, Burt RW, Johnson DA, Kirk LM, Litlin S, Lieberman DA, Waye JD, Church J, Marshall JB, Riddell RH | title = Quality in the technical performance of colonoscopy and the continuous quality improvement process for colonoscopy: recommendations of the U.S. Multi-Society Task Force on Colorectal Cancer | journal = The American Journal of Gastroenterology | volume = 97 | issue = 6 | pages = 1296–1308 | date = June 2002 | pmid = 12094842 | doi = 10.1111/j.1572-0241.2002.05812.x | s2cid = 26250449 }}</ref><ref name = "pmid28555630">{{cite journal | vauthors = Rex DK, Boland CR, Dominitz JA, Giardiello FM, Johnson DA, Kaltenbach T, Levin TR, Lieberman D, Robertson DJ | title = Colorectal Cancer Screening: Recommendations for Physicians and Patients from the U.S. Multi-Society Task Force on Colorectal Cancer | journal = The American Journal of Gastroenterology | volume = 112 | issue = 7 | pages = 1016–1030 | date = July 2017 | pmid = 28555630 | doi = 10.1038/ajg.2017.174 | publisher = Ovid Technologies (Wolters Kluwer Health) | s2cid = 6808521 }}</ref>

Among people who have had an initial colonoscopy that found no polyps, the risk of developing colorectal cancer within five years is extremely low. Therefore, there is no need for those people to have another colonoscopy sooner than five years after the first screening.<ref>{{cite journal | vauthors = Imperiale TF, Glowinski EA, Lin-Cooper C, Larkin GN, Rogge JD, Ransohoff DF | title = Five-year risk of colorectal neoplasia after negative screening colonoscopy | journal = The New England Journal of Medicine | volume = 359 | issue = 12 | pages = 1218–1224 | date = September 2008 | pmid = 18799558 | doi = 10.1056/NEJMoa0803597 | doi-access = free }}</ref><ref>[http://newswise.com/articles/view/544318/ No Need to Repeat Colonoscopy Until 5 Years After First Screening] {{Webarchive|url=https://web.archive.org/web/20181216032223/https://www.newswise.com//articles/view/544318/ |date=16 December 2018 }} Newswise, Retrieved on 17 September 2008.</ref>

Some medical societies in the US recommend a screening colonoscopy every ten years beginning at age 50 for adults without increased risk for colorectal cancer.<ref name="coloscreen">{{cite journal | vauthors = Winawer S, Fletcher R, Rex D, Bond J, Burt R, Ferrucci J, Ganiats T, Levin T, Woolf S, Johnson D, Kirk L, Litin S, Simmang C | title = Colorectal cancer screening and surveillance: clinical guidelines and rationale-Update based on new evidence | journal = Gastroenterology | volume = 124 | issue = 2 | pages = 544–560 | date = February 2003 | pmid = 12557158 | doi = 10.1053/gast.2003.50044 | doi-access = free }}</ref> Research shows that the risk of cancer is low for 10 years if a high-quality colonoscopy does not detect cancer, so tests for this purpose are indicated every ten years.<ref name="coloscreen"/><ref name="AGAfive">{{Citation|author1=American Gastroenterological Association |author1-link=American Gastroenterological Association |title=Five Things Physicians and Patients Should Question |publisher=[[American Gastroenterological Association]] |work=Choosing Wisely: an initiative of the [[ABIM Foundation]] |url=http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_AGA.pdf |access-date=17 August 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120809143636/http://choosingwisely.org/wp-content/uploads/2012/04/5things_12_factsheet_AGA.pdf |archive-date=9 August 2012 }}</ref>

Colonoscopy screening is associated with approximately two-thirds fewer deaths due to colorectal cancers on the left side of the colon, and is not associated with a significant reduction in deaths from right-sided disease. It is speculated that colonoscopy might reduce rates of death from colon cancer by detecting some colon polyps and cancers on the left side of the colon early enough that they may be treated, and a smaller number on the right side.<ref name="Baxter09">{{cite journal | vauthors = Baxter NN, Goldwasser MA, Paszat LF, Saskin R, Urbach DR, Rabeneck L | title = Association of colonoscopy and death from colorectal cancer | journal = Annals of Internal Medicine | volume = 150 | issue = 1 | pages = 1–8 | date = January 2009 | pmid = 19075198 | doi = 10.7326/0003-4819-150-1-200901060-00306 | doi-access = free | url = http://www.media.dssimon.com/taperequest/acp50_study.pdf | archive-url = https://web.archive.org/web/20120118213536/http://www.media.dssimon.com/taperequest/acp50_study.pdf | archive-date=18 January 2012 }}</ref>

Since polyps often take 10 to 15 years to transform into cancer in someone at average risk of colorectal cancer, guidelines recommend 10 years after a normal screening colonoscopy before the next colonoscopy. (This interval does not apply to people at high risk of colorectal cancer or those who experience symptoms of the disease.)<ref>{{cite web | work = Cancerconnect | url = http://news.cancerconnect.com/interval-between-colonoscopies-may-be-shorter-than-recommended/ | title = Interval between Colonoscopies May be Shorter than Recommended | archive-url = https://web.archive.org/web/20110807154552/http://news.cancerconnect.com/interval-between-colonoscopies-may-be-shorter-than-recommended/ | archive-date=7 August 2011 | access-date = 2 June 2011 }}</ref><ref name="goodwin">{{cite journal | vauthors = Goodwin JS, Singh A, Reddy N, Riall TS, Kuo YF | title = Overuse of screening colonoscopy in the Medicare population | journal = Archives of Internal Medicine | volume = 171 | issue = 15 | pages = 1335–1343 | date = August 2011 | pmid = 21555653 | pmc = 3856662 | doi = 10.1001/archinternmed.2011.212 | url = http://archinte.ama-assn.org/cgi/content/short/archinternmed.2011.212 | access-date = 30 May 2011 | url-status = dead | archive-url = https://web.archive.org/web/20110901031030/http://archinte.ama-assn.org/cgi/content/short/archinternmed.2011.212 | archive-date = 1 September 2011 }}</ref>

The large [[Randomized controlled trial|randomized]] [[pragmatic clinical trial]] NordICC was the first published trial on the use of colonoscopy as a screening test to prevent colorectal cancer, related death, and death from any cause. It included 84,585 healthy men and women aged 55 to 64 years in Poland, Norway, and Sweden, who were randomized to either receive an invitation to undergo a single screening colonoscopy (invited group) or to receive no invitation or screening (usual-care group). Of the 28,220 people in the invited group, 11,843 (42.0%) underwent screening. A total of 15 people who underwent colonoscopy (0.13%) had major bleeding after polyp removal.

None of the participants experienced a [[colon perforation]] due to colonoscopy. After 10 years, an [[Intention-to-treat analysis|intention-to-screen analysis]] showed a significant [[relative risk reduction]] of 18% in the risk of colorectal cancer (0.98% in the invited group vs. 1.20% in the usual-care group). The analysis showed no significant change in the risk of death from colorectal cancer (0.28% vs. 0.31%) or in the risk of death from any cause (11.03% vs. 11.04%). To prevent one case of colorectal cancer, 455 invitations to colonoscopy were required.<ref name="Bretthauer2022">{{cite journal | vauthors = Bretthauer M, Løberg M, Wieszczy P, Kalager M, Emilsson L, Garborg K, Rupinski M, Dekker E, Spaander M, Bugajski M, Holme Ø, Zauber AG, Pilonis ND, Mroz A, Kuipers EJ, Shi J, Hernán MA, Adami HO, Regula J, Hoff G, Kaminski MF | title = Effect of Colonoscopy Screening on Risks of Colorectal Cancer and Related Death | journal = The New England Journal of Medicine | volume = 387 | issue = 17 | pages = 1547–1556 | date = October 2022 | pmid = 36214590 | doi = 10.1056/NEJMoa2208375 | hdl-access = free | s2cid = 252778114 | hdl = 10852/101829 }}</ref><ref name="NordICC">{{ClinicalTrialsGov|NCT00883792|The Northern-European Initiative on Colorectal Cancer (NordICC)}}</ref>

As of 2023, the CONFIRM trial, a randomized trial evaluating colonoscopy vs. FIT is currently ongoing.<ref>{{cite web|url=https://clinicaltrials.gov/ct2/show/NCT01239082|title=Colonoscopy Versus Fecal Immunochemical Test in Reducing Mortality From Colorectal Cancer (CONFIRM) - Full Text View - ClinicalTrials.gov|website=clinicaltrials.gov|access-date=25 February 2019|archive-date=26 February 2019|archive-url=https://web.archive.org/web/20190226050032/https://clinicaltrials.gov/ct2/show/NCT01239082|url-status=live}}</ref>

In 2021, the US spent $43 billion on cancer screening to prevent five cancers, with colonoscopies accounting for 55% of the total.<ref>{{Cite journal |pmid=39102723 |date=2024 |last1=Halpern |first1=M. T. |last2=Liu |first2=B. |last3=Lowy |first3=D. R. |last4=Gupta |first4=S. |last5=Croswell |first5=J. M. |last6=Doria-Rose |first6=V. P. |title=The Annual Cost of Cancer Screening in the United States |journal=Annals of Internal Medicine |volume=177 |issue=9 |pages=1170–1178 |doi=10.7326/M24-0375 }}</ref> The death rate from colon cancer has been on a linear decline for 40 years, falling by nearly 50 percent from the 1980s (when few were screened) to 2024; however, the increase in screening did not accelerate the decline.<ref>{{cite news |last1=Kolata |first1=Gina |title=$43 Billion Price Tag on Cancer Screening Each Year Spurs Debate |url=https://www.nytimes.com/2024/08/05/health/cancer-screening-tests-cost.html |access-date=7 August 2024 |work=The New York Times |date=7 August 2024}}</ref> Therefore, resources devoted to cancer screening would be better directed toward ensuring widespread access to effective cancer treatment.<ref>{{Cite journal |pmid=39102720 |date=2024 |last1=Welch |first1=H. G. |title=Dollars and Sense: The Cost of Cancer Screening in the United States |journal=Annals of Internal Medicine |volume=177 |issue=9 |pages=1275–1276 |doi=10.7326/M24-0887 }}</ref>