Anal cancer: Difference between revisions
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*[http://www.nci.nih.gov/cancertopics/pdq/treatment/anal/healthprofessional National Cancer Institute (U.S.): Anal Cancer: Information for Health Professionals] | *[http://www.nci.nih.gov/cancertopics/pdq/treatment/anal/healthprofessional National Cancer Institute (U.S.): Anal Cancer: Information for Health Professionals] | ||
*[http://www.plwc.org/anal People Living With Cancer (PLWC): Anal Cancer] | *[http://www.plwc.org/anal People Living With Cancer (PLWC): Anal Cancer] | ||
*[http://www.bidmc.org/YourHealth/ConditionsAZ.aspx?ChunkID=251634 Beth Israel Deaconess Medical Center: Anal cancer] | *[http://www.bidmc.org/YourHealth/ConditionsAZ.aspx?ChunkID=251634 Beth Israel Deaconess Medical Center: Anal cancer] | ||
Revision as of 14:32, 16 April 2009
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Overview
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WikiDoc Resources for Anal cancer |
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Articles |
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Most recent articles on Anal cancer Most cited articles on Anal cancer |
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Media |
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Powerpoint slides on Anal cancer |
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Evidence Based Medicine |
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Clinical Trials |
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Ongoing Trials on Anal cancer at Clinical Trials.gov Clinical Trials on Anal cancer at Google
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Guidelines / Policies / Govt |
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US National Guidelines Clearinghouse on Anal cancer
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Books |
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News |
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Commentary |
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Definitions |
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Patient Resources / Community |
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Patient resources on Anal cancer Discussion groups on Anal cancer Patient Handouts on Anal cancer Directions to Hospitals Treating Anal cancer Risk calculators and risk factors for Anal cancer
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Healthcare Provider Resources |
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Causes & Risk Factors for Anal cancer |
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Continuing Medical Education (CME) |
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International |
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Business |
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Experimental / Informatics |
Anal cancer is a type of cancer which arises from the anus, the distal orifice of the gastrointestinal tract. It is a distinct entity from the more common colorectal cancer. The etiology, risk factors, clinical progression, staging, and treatment are all different. Anal cancer is typically a squamous cell carcinoma that arises near the squamocolumnar junction.
Epidemiology
Incidence[1]
- In women and men who do not engage in anal intercourse with other men - 0.9/100,000
- In HIV negative men who engage in anal intercourse with other men - 35/100,000
- In HIV positive men who engage in anal intercourse with other men - (estimated) 60-70/100,000
Anal cancer is uncommon and accounts for only 4% of all cancers of the lower alimentary tract. There are estimated to be 4,650 new cases and 690 deaths from anal cancer in the United States in 2007.[2] Because it is rare and because it occurs in a body part that is rarely discussed, most people are unaware of its existence.
Risk factors
- Human papillomavirus (HPV) infection: An examination of squamous cell carcinoma tumor tissues from patients in Denmark and Sweden showed a high proportion of anal cancers to be positive for the types of HPV that are also associated with high risk of cervical cancer (90% of the tumors from women, 100% of the tumors from homosexual men, and 58% of tumors from heterosexual men).[3] In another study done, high-risk types of HPV, notably HPV-16, were detected in 84 percent of anal cancer specimens examined.[4]
- Sexual activity: Having multiple sex partners or having anal sex, due to the increased risk of exposure to the HPV virus.[5]
- Smoking: Current smokers are several times more likely to develop anal cancer compared with nonsmokers.[5]
- Immunosuppression, which is often associated with HIV infection.[5]
Prevention
Since many, if not most, anal cancers derive from Human Papilloma Virus infections, and since the HPV vaccine prevents infection by several strains of the virus, scientists surmise that HPV vaccination will prevent anal cancer. [6]
Screening
Anal pap smears similar to those used in cervical cancer screening have been studied experimentally for early detection of anal cancer in high-risk individuals.[7][8]
Treatment
Localized disease
Anal cancer is most effectively treated with surgery, and in early stage disease (i.e., localized cancer of the anus without metastasis to the inguinal lymph nodes), surgery is often curative. The difficulty with surgery has been the necessity of removing the anal sphincter, with concomitant fecal incontinence. For this reason, many patients with anal cancer have required permanent colostomies.
In more recent years, physicians have employed a combination strategy including chemotherapy and radiation treatments to reduce the necessity of debilitating surgery. This "combined modality" approach has led to the increased preservation of an intact anal sphincter, and therefore improved quality of life after definitive treatment. Survival and cure rates are excellent, and many patients are left with a functional sphincter. Some patients have fecal incontinence after combined chemotherapy and radiation. Biopsies to document disease regression after chemotherapy and radiation were commonly advised, but are not as frequent any longer. Current chemotherapy active in anal cancer includes cisplatin and 5-FU; mitomycin has also been used, but is associated with increased toxicity.
Metastatic or recurrent disease
Up to 10% of patients treated for anal cancer will develop distant metastatic disease. Metastatic or recurrent anal cancer is difficult to treat, and usually requires chemotherapy. Radiation is also employed to palliate specific locations of disease that may be causing symptoms. Chemotherapy commonly used is similar to other squamous cell epithelial neoplasms, such as platinum analogues, anthracyclines such as doxorubicin, and antimetabolites such as 5-FU and capecitabine.
Prognosis
See also
References
- ↑ Anal Carcinoma [1]
- ↑ National Cancer Institute: Anal Cancer [2]
- ↑ Danish Medical Bulletin. 2002 Aug;49(3):194-209
- ↑ New England Journal of Medicine. 1997 Nov 6;337(19):1350-8
- ↑ 5.0 5.1 5.2 American Cancer Society. "What Are the Risk Factors for Anal Cancer?"
- ↑ Template:Http://www.iht.com/articles/2007/01/31/healthscience/sncancer.php
- ↑ Cichoki, Mark. "Anal Papilloma Screening" on About.com
- ↑ Chiao EY, Giordano TP, Palefsky JM, Tyring S, El Serag H (2006). "Screening HIV-infected individuals for anal cancer precursor lesions: a systematic review". Clin. Infect. Dis. 43 (2): 223–33. doi:10.1086/505219. PMID 16779751.
External links
- Anal Warts, Anal Cancer, and Anal Pap Smears
- Anal Cancer and HPV in Men Who Have Sex With Men
- National Cancer Institute (U.S.): Anal Cancer: Information for Health Professionals
- People Living With Cancer (PLWC): Anal Cancer
- Beth Israel Deaconess Medical Center: Anal cancer
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