Anal cancer

For cancer of the colon or rectum, see Colorectal cancer.
Anal cancer

Diagram showing stage 1 anal cancer
Classification and external resources
Specialty Oncology
ICD-10 C21
DiseasesDB 31467
MeSH D001005

Anal cancer is a cancer (malignant tumor) which arises from the anus, the distal opening of the gastrointestinal tract. It is a distinct entity from the more common colorectal cancer.

Anal cancer is typically an anal squamous cell carcinoma that arises near the squamocolumnar junction, often linked to human papillomavirus (HPV) infection. It may be keratinizing (basaloid) or non-keratinizing (cloacogenic). Other types of anal cancer are adenocarcinoma, lymphoma, sarcoma or melanoma. From data collected 2004-2010, the relative five year survival rate in the United States is 65.5%, though individual rates may vary depending upon the stage of cancer at diagnosis and the response to treatment.[1]

Signs and symptoms

Symptoms of anal cancer can include pain or pressure in the anus or rectum, a change in bowel habits, a lump near the anus, rectal bleeding, itching or discharge. Bleeding may be severe.[2][3]

Risk factors


Most anal cancers are squamous cell carcinomas (epidermoid carcinomas), that arises near the squamocolumnar junction. It may be keratinizing (basaloid) or non-keratinizing (cloacogenic).

Other types of anal cancer are adenocarcinoma, lymphoma, sarcoma or melanoma.


Since many, if not most, anal cancers derive from HPV infections, and since the HPV vaccine before exposure to HPV prevents infection by some strains of the virus and has been shown to reduce the incidence of potentially precancerous lesions,[14] scientists surmise that HPV vaccination may reduce the incidence of anal cancer.[15]

On 22 December 2010, the U.S. Food and Drug Administration approved Gardasil vaccine to prevent anal cancer and pre-cancerous lesions in males and females aged 9 to 26 years. The vaccine has been used before to help prevent cervical, vulvar, and vaginal cancer, and associated lesions caused by HPV types 6, 11, 16, and 18 in women.[16]


Anal Pap smears similar to those used in cervical cancer screening have been studied for early detection of anal cancer in high-risk individuals.[17] In 2011, the HIV clinic at Jackson Memorial Hospital implemented a program to enhance access to anal cancer screening for HIV-positive men. Nurse practitioners perform anal Papanicolaou screening, and men with abnormal results receive further evaluation with high-resolution anoscopy. The program has helped identify many precancerous growths, allowing them to be safely removed.[18]


Localised disease

Localised disease (carcinoma-in-situ) and the precursor condition, anal intraepithelial neoplasia (anal dysplasia or AIN) can be ablated with minimally invasive methods such as Infrared Photocoagulation.[19]

Previously, anal cancer was treated with surgery, and in early stage disease (i.e., localised 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 internal and external anal sphincter, with concomitant fecal incontinence. For this reason, many patients with anal cancer have required permanent colostomies.

Current gold-standard therapy is chemotherapy and radiation treatment to reduce the necessity of debilitating surgery.[20] 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 consists of continuous infusion 5-FU over four days with bolus mitomycin given concurrently with radiation. 5-FU and cisplatin are recommended for metastatic anal cancer.[21]

Metastatic or recurrent disease

10 to 20% of patients treated for anal cancer will develop distant metastatic disease following treatment.[22] 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. J.D. Hainsworth developed a protocol that includes Taxol and Carboplatinum along with 5-FU. Median survival rates for patients with distant metastases ranges from 8 to 34 months.[22]



The American Cancer Society estimated that in 2014 about 7,060 new cases of anal cancer would be diagnosed in the United States (4,430 in women and 2,630 in men) .[23] It is typically found in adults, average age early 60s.[23]

In the United States, an estimated 800 to 900 people die of anal cancer annually.[23]


Anal cancer accounts for less than 1% of all cancer cases and deaths in the UK. Around 1,200 people were diagnosed with the disease in 2011, and around 310 people died in 2012.[24]


Worldwide in 2002 there were an estimated 30,400 new cases of anal cancer.[6] With approximately equal fractions in the developing (15,900) and developed (14,500) countries.[6] An estimated 90% (27,400) were attributable to Human papillomavirus (HPV).[6]

See also


  1. "SEER Stat Fact Sheets: Anal Cancer". NCI. Retrieved 22 December 2014.
  2. National Cancer Institute. Anal Cancer Treatment (PDQ) Patient Version. Archived July 14, 2009, at the Wayback Machine. 13 June 2008. Accessed 26 June 2009.
  3. Stanley, Margaret A; Winder, David M; Sterling, Jane C; Goon, Peter KC (2012). "HPV infection, anal intra-epithelial neoplasia (AIN) and anal cancer: current issues". BMC Cancer. 12 (1): 398. doi:10.1186/1471-2407-12-398. ISSN 1471-2407.
  4. Frisch M (August 2002). "On the etiology of anal squamous carcinoma". Danish Medical Bulletin. 49 (3): 194–209. PMID 12238281.
  5. Frisch M, Glimelius B, van den Brule AJ, et al. (November 1997). "Sexually transmitted infection as a cause of anal cancer". N. Engl. J. Med. 337 (19): 1350–8. doi:10.1056/NEJM199711063371904. PMID 9358129.
  6. 1 2 3 4 Parkin DM (2006). "The global health burden of infection-associated cancers in the year 2002". Int. J. Cancer. 118 (12): 3030–44. doi:10.1002/ijc.21731. PMID 16404738.
  7. 1 2 3 "Anal Cancer". American Cancer Society. Retrieved 2014-12-22.
  8. 1 2 3 "Fred Hutchinson Cancer Research Center, Changing Trends in Sexual Behavior May Explain Rising Incidence of Anal Cancer Among American Men and Women". Fred Hutchinson Cancer Research Center ( 2004-07-06. Retrieved 2010-04-21.
  9. "STD Facts – HPV and Men". Archived from the original on 14 September 2007. Retrieved 2007-08-17.
  10. Natia Esiashvili; Jerome Landry; Richard H. Matthews (2007). "Carcinoma of the Anus Management". Armenian Health Network, Archived from the original on 5 February 2008. Retrieved 2008-01-22.
  11. Lin AY, Gridley G, Tucker M (1995). "Benign anal lesions and anal cancer". The New England Journal of Medicine. 332 (3): 190–1. doi:10.1056/NEJM199501193320314. PMID 7695719.
  12. Saleem AM, Paulus JK, Shapter AP, Baxter NN, Roberts PL, Ricciardi R (2011). "Risk of anal cancer in a cohort with human papillomavirus-related gynecologic neoplasm". Obstetrics and Gynecology. 117 (3): 643–9. doi:10.1097/AOG.0b013e31820bfb16. PMID 21343768.
  13. Sink JD, Kramer SA, Copeland DD, Seigler HF (1978). "Cloacogenic carcinoma". Annals of Surgery. 188 (1): 53–9. doi:10.1097/00000658-197807000-00009. PMC 1396653Freely accessible. PMID 666378.
  14. ""Gardasil, Merck's Cervical Cancer Vaccine, Demonstrated Efficacy in Preventing HPV-Related Disease in Males in Phase III Study: Pivotal Study Evaluating Efficacy of Gardasil in Males in Preventing HPV 6, 11, 16 and 18-Related External Genital Lesions".". Merck Research and Development News. ( Archived from the original on 15 December 2008. Retrieved 2008-11-15.
  15. Tuller, David (2007-01-31). "HPV vaccine may help to prevent anal cancer". International Herald Tribune. Retrieved 2014-12-22.
  16. US approves anal cancer vaccine
  17. 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.
  18. "Hospital HIV Clinic Offers Convenient, Proactive Screening for Anal Cancer, Enabling Identification and Treatment of Precancerous Lesions". Agency for Healthcare Research and Quality. 2013-04-10. Retrieved 2013-05-10.
  19. Goldstone SE, Kawalek AZ, Huyett JW (2005). "Infrared coagulator: a useful tool for treating anal squamous intraepithelial lesions". Diseases of the Colon and Rectum. 48 (5): 1042–54. doi:10.1007/s10350-004-0889-0. PMID 15868241.
  20. National Comprehensive Cancer Network. "NCCN Clinical Practice Guidelines in Oncology: Anal Carcinoma. V 1.2013" (PDF).
  21. Ghosn M, Kourie HR, Abdayem P, Antoun J, Nasr D (2015). "Anal cancer treatment: current status and future perspectives". World J. Gastroenterol. 21 (8): 2294–302. doi:10.3748/wjg.v21.i8.2294. PMC 4342904Freely accessible. PMID 25741135.
  22. 1 2 Dewdney A, Rao S (2012). "Metastatic squamous cell carcinoma of the anus: time for a shift in the treatment paradigm?". ISRN Oncology. 2012: 756591. doi:10.5402/2012/756591. PMC 3352602Freely accessible. PMID 22619735.
  23. 1 2 3 "Detailed Guide: Anal Cancer What Are the Key Statistics About Anal Cancer?". Archived from the original on 10 October 2008. Retrieved 2008-11-18.
  24. "Anal Cancer Statistics". Cancer Research UK. Retrieved 27 October 2014.

External links

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