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Anal Cancer

While anal cancer is fairly rare and much less common than colon or rectal cancer, the number of new cases in the United States has been on the rise for several decades.  For 2017, the American Cancer Society estimates about 8,000 new cases and 1,000 deaths due to anal cancer.


The majority of anal cancers consist of squamous cell carcinomas, which are the skin cells that line the lower anal canal and anal opening.  Anal cancer is different from rectal cancer, and there is often confusion due to the anatomic proximity.  However the two diseases and treatments are different.  The vast majority of anal cancer (more than 90%) is linked to human papilloma virus (HPV) infection.  HPV is a group of more than 150 related viruses (like cousins in a family) with the subtypes HPV-6, -11, -16 or -18 being most likely to cause anal cancer.  Other sub-types carry a high risk of cervical, vaginal, vulvar, penile, and throat cancers.


Both men and women can develop anal cancer, however, the risk of being diagnosed is slightly higher for women. 



Because the vast majority of anal squamous cancer is due to HPV infection, and because HPV is a sexually transmitted infection, there is significant anxiety and confusion surrounding this disease.  There are several risk factors which increase the risk of developing HPV related anal cancer, however it is important to note that HPV is so common that most men and women who have sex and intimate contact with another person are likely to have come into contact with HPV at some point in their lives.  It is a viral infection common within both the heterosexual and homosexual population.  It is also important to note that it is not necessary to have anal intercourse to have anal canal HPV infection.  Through the natural temperature and humidity environment of the anogenital region, the virus can spread throughout this region, from front to back and back to front.  The HPV virus may be able to persist in unseen locations such as the cervix and vagina in women and the anal canal in both men and women. Left un-diagnosed and untreated, HPV infection in these areas can mutate over time to cause anal squamous cell carcinoma. 

There are many resources available on the Internet that speak to both the subject of anal canal cancer and anogenital HPV infection.  One website that we like, and recommend as a good place to start, is The HPV and Anal Cancer Foundation .


The symptoms of anal cancer can also mimic the symptoms of hemorrhoids.  These symptoms include:

  • palpable anal mass,

  • pain,

  • bleeding,

  • anal itching,

  • pain during the bowel movement or

  • increasing difficulty having a bowel movement with a smaller sized stool. 


Any of these persistent symptoms should be evaluated by a physician.


As colon and rectal surgeons, we are often the doctors who make the initial diagnosis of anal cancer.  We become the "quarterback” who organize the additional diagnostic workup, provide referrals to medical and radiation oncologists, coordinate additional radiologic evaluations, and provide context and guidance both to the primary care physician and to patient and family.


Fortunately, there are excellent treatments for anal cancer, when caught early, that will avoid the need for permanent colostomy.  Radiation and chemotherapy are the mainstays of treatment with excellent cure and survival rates related to the initial stage of disease.  Through our affiliations with cancer oncologists such as the Rocky Mountain Cancer Center, and Cancer Centers of Colorado, we refer patients to experts and specialists familiar with treating this disease.  Importantly these oncology experts also participate in national clinical trials as we seek to improve the nonsurgical management of both local and metastatic disease.


Our participation as surgeons continues well beyond the initial diagnosis.  Following completion of initial nonsurgical chemoradiation management, we provide ongoing surveillance examination to ensure there is no persistence or recurrence within the anorectal region.  We consider our relationship with our patients to be a partnership, extending well into the future.




We firmly believe in the beneficial results of obtaining the HPV vaccine, especially for both boys and girls starting at age 11 or 12.


For persons who are older than age 11-12 and did not previously receive the vaccine, there may still be benefit. Please refer to the CDC website link above for details and information.


For those persons already infected with HPV, who have not previously obtained the vaccine, there still may be a benefit in obtaining the vaccine. We can offer you guidance and recommendations.


It is important that the embarrassment or anxiety of having a painful, itchy or palpable lump in the anal region not prevent you from seeking assessment and help. Please call our office for appointment.


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