Colorectal cancer: Difference between revisions

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imported>Robert Badgett
imported>Robert Badgett
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{{subpages}}
==Pathophysiology==
Colorectal cancer probably arises from colorectal polyps.<ref name="pmid17167138">{{cite journal |author=Levine JS, Ahnen DJ |title=Clinical practice. Adenomatous polyps of the colon |journal=N. Engl. J. Med. |volume=355 |issue=24 |pages=2551–7 |year=2006 |month=December |pmid=17167138 |doi=10.1056/NEJMcp063038 |url=http://content.nejm.org/cgi/content/full/355/24/2551 |issn=}}</ref> Adenomatous polyps convert to cancers at a rate of about 1% per year.<ref name="pmid3653628">{{cite journal |author=Stryker SJ, Wolff BG, Culp CE, Libbe SD, Ilstrup DM, MacCarty RL |title=Natural history of untreated colonic polyps |journal=Gastroenterology |volume=93 |issue=5 |pages=1009–13 |year=1987 |month=November |pmid=3653628 |doi= |url= |issn=}}</ref>
==Treatment==
==Treatment==
{{PDQ-treatment|http://www.cancer.gov/cancertopics/pdq/treatment/colon/HealthProfessional/page5}}
{{PDQ-treatment|http://www.cancer.gov/cancertopics/pdq/treatment/colon/HealthProfessional/page5}}
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;Cetuximab
;Cetuximab
Cetuximab, an I<sub>g</sub>G1 chimeric monoclonal antibody against epidermal growth factor receptor, may help according to a [[randomized controlled trial]].<ref name="pmid18003960">{{cite journal |author=Jonker DJ, O'Callaghan CJ, Karapetis CS, ''et al'' |title=Cetuximab for the treatment of colorectal cancer |journal=N. Engl. J. Med. |volume=357 |issue=20 |pages=2040–8 |year=2007 |pmid=18003960 |doi=10.1056/NEJMoa071834}}</ref>
Cetuximab, an I<sub>g</sub>G1 chimeric monoclonal antibody against epidermal growth factor receptor, may help according to a [[randomized controlled trial]].<ref name="pmid18003960">{{cite journal |author=Jonker DJ, O'Callaghan CJ, Karapetis CS, ''et al'' |title=Cetuximab for the treatment of colorectal cancer |journal=N. Engl. J. Med. |volume=357 |issue=20 |pages=2040–8 |year=2007 |pmid=18003960 |doi=10.1056/NEJMoa071834}}</ref>
==Prognosis==
{{Image|5-Year Colorectal Cancer Relative Survival Rates By Year Dx By Cancer Site All Ages, All Races, Both Sexes 1975-2000.jpg|right|350px|5-Year Colorectal Cancer Relative Survival Rates By Year Dx By Cancer Site All Ages, All Races, Both Sexes 1975-2000. From [http://www.cancer.gov/ National Cancer Institute], [http://seer.cancer.gov/faststats/selections.php?run=runit&series=cancer&paramSubSite=&data=4&statistic=6&year=200805&race=1&sex=1&age=1&output=2&cancer[]=40#Output SEER database].}}
===Staging information===
{{PDQ-staging|http://www.cancer.gov/cancertopics/pdq/treatment/colon/HealthProfessional/page4}}
==Screening==
{{main|colonic polyp}}
A [[clinical practice guideline]] by the [[US Preventive Services Task Force]] has addressed colorectal cancer:<ref name="pmid18838716">{{cite journal |author= |title=Screening for Colorectal Cancer: U.S. Preventive Services Task Force Recommendation Statement |journal=Annals of Internal Medicine |volume= |issue= |pages= |year=2008 |month=October |pmid=18838716 |doi= |url=http://www.annals.org/cgi/content/full/0000605-200811040-00243v1 |issn=}}</ref>
* "recommends screening for colorectal cancer using fecal  occult blood testing, sigmoidoscopy, or colonoscopy in adults,  beginning at age 50 years and continuing until age 75 years."
* "recommends against routine screening for colorectal  cancer in adults 76 to 85 years of age. There may be considerations  that support colorectal cancer screening in an individual patient."
* "recommends against screening for colorectal cancer in  adults older than age 85 years"
* "the evidence is insufficient to assess  the benefits and harms of computed tomographic colonography and  fecal DNA testing"
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
* 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.
==Prevention==
===Aspirin chemoprophylaxis===
A [[clinical practice guideline]] by the [http://www.ahrq.gov/clinic/uspstfix.htm U.S. Preventive Services Task Force (USPSTF)] recommended against taking [[aspirin]] ([http://www.ahrq.gov/clinic/3rduspstf/ratings.htm grade D recommendation]).<ref name="pmid17339621">{{cite journal |author= |title=Routine aspirin or nonsteroidal anti-inflammatory drugs for the primary prevention of colorectal cancer: U.S. Preventive Services Task Force recommendation statement |journal=Ann. Intern. Med. |volume=146 |issue=5 |pages=361-4 |year=2007 |id=pmid=17339621 |doi=}} PMID 17339621</ref> The Task Force acknowledged that aspirin may reduce the incidence of colorectal cancer, but "concluded that harms outweigh the benefits of aspirin and NSAID use for the prevention of colorectal cancer". A subsequent [[meta-analysis]] concluded "300 mg or more of aspirin a day for about 5 years is effective in primary prevention of colorectal cancer in randomised controlled trials, with a latency of about 10 years".<ref name="pmid17499602">{{cite journal |author=Flossmann E, Rothwell PM |title=Effect of aspirin on long-term risk of colorectal cancer: consistent evidence from randomised and observational studies |journal=Lancet |volume=369 |issue=9573 |pages=1603-13 |year=2007 |pmid=17499602 |doi=10.1016/S0140-6736(07)60747-8}} PMID 17499602</ref> However, long-term doses over 81 mg per day may increase bleeding events.<ref name="pmid17488967">{{cite journal |author=Campbell CL, Smyth S, Montalescot G, Steinhubl SR |title=Aspirin dose for the prevention of cardiovascular disease: a systematic review |journal=JAMA |volume=297 |issue=18 |pages=2018-24 |year=2007 |pmid=17488967 |doi=10.1001/jama.297.18.2018}} PMID 17488967</ref>
===Calcium===
A [[meta-analysis]] by the [[Cochrane Collaboration]] of [[randomized controlled trial]]s published through 2002  concluded "Although the evidence from two RCTs suggests that calcium supplementation might contribute to a moderate degree to the prevention of colorectal adenomatous polyps, this does not constitute sufficient evidence to recommend the general use of calcium supplements to prevent colorectal cancer.".<ref name="pmid16034903">{{cite journal |author=Weingarten MA, Zalmanovici A, Yaphe J |title=Dietary calcium supplementation for preventing colorectal cancer and adenomatous polyps |journal=Cochrane database of systematic reviews (Online) |volume= |issue=3 |pages=CD003548 |year=2005 |pmid=16034903 |doi=10.1002/14651858.CD003548.pub3}}</ref> Subsequently, one [[randomized controlled trial]] by the [[Women's Health Initiative]] (WHI) reported negative results.<ref name="pmid16481636">{{cite journal |author=Wactawski-Wende J, Kotchen JM, Anderson GL, ''et al'' |title=Calcium plus vitamin D supplementation and the risk of colorectal cancer |journal=N. Engl. J. Med. |volume=354 |issue=7 |pages=684-96 |year=2006 |pmid=16481636 |doi=10.1056/NEJMoa055222}}</ref> A second [[randomized controlled trial]] reported reduction in all cancers, but had insufficient colorectal cancers for analysis.<ref name="pmid17556697">{{cite journal |author=Lappe JM, Travers-Gustafson D, Davies KM, Recker RR, Heaney RP |title=Vitamin D and calcium supplementation reduces cancer risk: results of a randomized trial |journal=Am. J. Clin. Nutr. |volume=85 |issue=6 |pages=1586-91 |year=2007 |pmid=17556697 |doi=|url=http://www.ajcn.org/cgi/content/full/85/6/1586}}</ref>
==References==
<references/>

Revision as of 21:54, 24 December 2008

Treatment

Colorectal cancer treatment information from the National Cancer Institute's Physician Data Query


Medications

Cetuximab

Cetuximab, an IgG1 chimeric monoclonal antibody against epidermal growth factor receptor, may help according to a randomized controlled trial.[1]

  1. ↑ Jonker DJ, O'Callaghan CJ, Karapetis CS, et al (2007). "Cetuximab for the treatment of colorectal cancer". N. Engl. J. Med. 357 (20): 2040–8. DOI:10.1056/NEJMoa071834. PMID 18003960. Research Blogging.
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