Annual anal PAP smears can help identify HIV-positive individuals who develop abnormal anal cytology, according to a US study presented to the 45th Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington DC last month. The investigators, from Rochester New York, found that being gay or bisexual and a history of anal intercourse were predictive of developing abnormal anal cytology. However, neither CD4 cell count nor use of antiretroviral therapy was associated with abnormal anal findings.
A second study presented to the conference found, however, that in HIV-positive women with human papilloma virus (HPV) infection, decreasing CD4 cell count increased the risk of developing abnormal cells in the cervix or anus.
Rochester study
Studies have suggested that there are excess rates of anal cancer in HIV-positive individuals. The value of using PAP smears to detect pre-cancerous cell changes in the anus has not been determined.
Therefore investigators from an HIV outpatient clinic conducted a retrospective review of the records of individuals who underwent anal PAP smears on two consecutive years between 2002 and 2004. The demographic, physical and laboratory characteristics of the individuals who developed abnormal anal cytology between the first and second smears were compared to patients whose findings remained normal.
Out of a total clinic population of 800, some 597 patients had at least one anal PAP smear and 150 individuals had two consecutive smears. Of these, 38 individuals developed abnormal anal cytology between the first and second smears.
The overwhelming majority (91%) of these patients were male, the average age was 45 years, and the average duration of HIV infection was twelve years. Just under two-thirds (63%) of individuals were Caucasian and 59% of men said that they were gay or bisexual.
Analysis indicated that Caucasian race (p = 0.03), gay of bisexual orientation (p = 0.03), a history of anal intercourse (p = 0.005) and not smoking (p = 0.02) were all significantly associated with developing abnormal anal cytology.
The investigators also found that there was a trend of borderline statistical significance (p = 0.055) for individuals developing abnormal cytology to have symptoms on examination (tags and condylomata).
However a CD4 cell count below 200 cells/m3 and CDC HIV disease stage were not predictive of developing abnormal anal cytology, but the use of antiretroviral therapy was not protective.
HIV-positive women with HPV infection
The results of anal or cervical PAP smears or biopsies obtained from 161 HIV-positive women with HPV infection in San Francisco between 2000 and 2004 were retrospectively analysed.
The investigators wished to determine if there was an association of time between age, CD4 cell count, HIV viral load, the use of antiretroviral therapy and the risk of developing abnormal cells in the cervix or anus.
In total 33% of women with a CD4 cell count below 200 cells/mm3 had low or high grade abnormal abnormal cells in either their cervix or anus compared to 21% of women with a CD4 cell count between 201 - 350 cells/mm3, 4% of women with a CD4 cell count between 351 - 500 cells/mm3 and 10% of women with a CD4 cell count above 500 cells/mm3.
“In general, increasing atypia as measured by cervical PAP smears was significantly associated with decreasing CD4 cells. The implications of this observation on antiretroviral therapy initiation and immune recovery among women with HPV disease warrant further investigation”, conclude the investigators.
Greenberg LG et al. Risk factors for abnormal anal PAP smear conversion in HIV-positive patients. 45th Interscience Conference on Antimicrobial Agents and Chemotherapy, abstract H-1490, Washington DC, 2005.
Young TP et al. CD4 cell count and viral load associations with abnormal cervical and anal PAP smears in HIV-infected women. 45th Interscience Conference on Antimicrobial Agents and Chemotherapy, abstract H-1491, Washington DC, 2005.