Title: Detection of Anal Dysplasia through Anal Pap Testing in the HIV-infected Individuals

Written by: Nancy Chow, RN, BScN
Immunodeficiency Clinic, Burrard Building
St.Paul's Hospital, 1081 Burrard Street
Vancouver, BC V6Z 1Y6
(T) 604-806-9303 (F) 604-806-9311
nchow@providencehealth.bc.ca

Background: Anal cancer is infrequent in the general population; currently at the rate of approximately one per 100,000 (Chiao, et al.,2005). However, the incidence of anal cancer in HIV-infected men who have sex with men (MSM) has been increasing at rates of 60-160 per 100,000 (Salit, et al., 2010). Rates of anal cancer among HIV-infected MSM are comparable to rates of cervical cancer in women prior to the initiation of routine screening for cervical dysplasia. Most of the literature pertainng to HPV disease has focused on cervical abnormalities, but anal infections are actually more common. Several studies have also shown that anal cancer is increasing in HIV-infected individuals with the advent of highly active anti-retroviral therapy, probably because of the prolonged life span due to therapy.

What is Anal Dysplagia? It refers to abnormal structural changes in the cells that can happen to the cells that make up the lining (mucosa) of the anal canal. Similar to cervical dysplasia, it is a pre-cancerous condition where abnormal cells clustered together to form a lesion. Anal dysplasia occurs mainly in two places: in the "junction," where the anal canal meets the rectum; and in the peri-anal skin, just outside of the anal opening. These cells may then progress from low-grade lesions to high-grade lesions.

What causes Anal Dysplagia? It is most commonly linked to human papillomavirus (HPV), the same virus that causes warts and the most common sexually transmitted disease (Salit, 2010). HPV is a common virus with at least 70 strains, many of which can be transmitted sexually.

Under normal circumstances our cells make certain proteins that help prevent dysplasia and cancer. HPV can shut off these proteins, allowing dysplasia to develop. People with HIV, including women, are at increased risk for anal dysplasia. HIV seems to interact with HPV to make these changes more likely. Furthermore, anal dysplasia has been clearly associated with HIV and particularily with a decrease in CD4+ cell count.

Risk factors for Anal Dysplasia: Individual that are at risk for anal dysplagia include but are not limited to the following:

  • Men and women who have receptive anal intercourse (RAI). Studies show that the rates of anal cancer are much higher in men who have anal sex with men (MSM) and are HIV positive, which leads to up to the next point.
  • HIV infection: those who are HIV+ are especially at risk because they are at higher risk for persistent HPV infection. And unlike other sexually transmitted diseases, condoms are not effective in preventing HPV infection.
  • CD4 count < 200cells/L. Those with a CD4 count lower than 200 have a low immune system and abnormal cell changes can occur with no or little resistance.
  • Individuals with a history of anal warts are at risk of getting anal cancer.
  • Having multiple sex partners increases the likelihood of getting anal HPV.
  • High grade cervical/vulvar dysplasia women with high grade cervica/vulvar dsyplasia have a higher chance.
  • Lastly, cigarette smoking is another risk factor for anal dysplasia.