Correlation of HIV infection, CD4 cell count and the risk of anal cancer in Thai MSM
J. Barisri, T. Pankam, C. Pakam, P. Noysamdang, S. Pattanachaiwit, R. Wongkanya, S. Sirivichayakul, M. Kongpattanayothin, N. Theeratakulphisarn, P. Phanuphak
AIDS Research Center The Thai Red Cross, Bangkok, Thailand
Background: Human Papilloma Virus (HPV) is the causative agent of cervical cancer in women and anal cancer in men who have sex with men (MSM) with unprotected receptive anal intercourse. HIV-infected MSM have a two-fold higher chance in developing anal cancer than HIV-uninfected MSM. Anal PAP smear is a reliable screening test for early detection of anal cancer. We determine the correlation of HIV infection and the level of CD4 cell count in HIV-infected individuals with the degree of anal dysplasia as seen in anal Pap smear.
Methods: MSM who requested anal Pap smear at the Thai Red Cross Anonymous Clinic in Bangkok between 2007and 2008 were included in the analysis. Those who have never had an HIV test or those whose previous test was negative were counseled to have an anti-HIV test according to the provider-initiated counseling and testing (PICT) approach. The clients were classified as HIV-positive, HIV-negative and HIV-unknown for those who did not want to have a test. CD4 cell count was done in all HIV-positive individuals around the time of Pap smear.
Results: A total of 570 MSM volunteered for anal Pap smear during the study period. 365 (64%) were HIV-positive, 140 (24.6%) were HIV-negative. Mean age was 31 (range19-62). Pap smear was adequate in 557 specimens (97.7%). Abnormal Pap smear was found in 27% and 14% of HIV-positive and HIV-negative individuals, respectively (p< 0.05). Among HIV-infected MSM, abnormal Pap smear was found in 41%, 25% and 22% of those whose CD4 was < 200, 200-350 and >350 cells per cu.mm., respectively (p< 0.05 between CD4< 200 vs. >200).
Conclusions: Similar to the studies in the Western world, abnormal anal cytology was found twice higher in HIV-infected Thai MSM as compared to HIV-negative MSM (p< 0.05). Although level of immunodeficiency correlate significantly with abnormal anal cytology.