Anal Cancer Screening Warranted for Heterosexuals With HIV, Not Just MSM
Heterosexual HIV-infected men and women have a high prevalence of markers associated with anal cancer, such as infection with high-risk human papillomavirus (hr-HPV) and cytological abnormalities, according to study results presented at IDWeek 2013. These data suggest that anal cancer screening should be conducted for all HIV-infected patients, not only men who have sex with men (MSM).
Previously, abnormal anal cytology (AC) and hr-HPV were found to be highly prevalent among HIV-infected MSM. Data on seropositive women and men who have sex with women (MSW), however, are limited. The reported prevalence of abnormal AC and HPV in HIV-infected women varies from 10.5% to 38% and from 16% to 90%, respectively; while in MSW, it ranges from 20% to 36% and from 15% to 59%, respectively.
To gather more information on the prevalence of these two markers, as well as to evaluate the performance of hr-HPV and abnormal AC in detecting high-grade anal dysplasia (AIN2+), Sumanth Gandra, M.D., M.P.H., and colleagues from the University of Massachusetts Medical School performed a retroactive cohort study with all of the HIV-infected patients of the university clinic who underwent routine screening for anal cancer between Jan. 1, 2011, and Jan. 31, 2013. It included the results of the HPV and anal cytology tests, as well as a review of the medical records of patients who underwent high-resolution anoscopy (HRA) because of abnormal AC or a positive hr-HPV.
Of the total cohort of 221 individuals, 67% were men (of whom 73% were MSM and 27% were MSW) and 33% were women. Infection with hr-HPV was detected in 43% (54% MSM, 28% MSW, 27% women) and cytological abnormalities were found in 39% (48% MSM, 28% MSW, 34% of women).
Of the 117 patients (53%) with abnormal screening tests, 27% had both hr-HPV infection and abnormal AC, 14% had only hr-HPV infection and 13% had only abnormal AC. The cytology results were normal in 50%, non-diagnostic in 10%, ASCUS (atypical cells of undetermined significance) in 23%, LSIL (low-grade squamous intraepithelial lesion) in 14% and HSIL (high-grade squamous intraepithelial lesion) in 2%.
HRA, an examination routinely used to detect anal cancer precursor lesions, was performed in 68 patients due to either abnormal cytology or hr-HPV infection. Of these, 22 patients displayed AIN2+ (17 were MSM) and all had hr-HPV. None of the 14 patients who were negative for hr-HPV, and who underwent HRA for abnormal cytology, had AIN2+. The data gathered from the 68 patients who underwent HRA suggest that hr-HPV is a better correlate to AIN2+ when compared with anal cytology (rs = 0.35 vs. -0.03).
Gandra and his group state that the prevalence of abnormal AC in MSW and women in their cohort is within the previously reported range, but the prevalence of hr-HPV infection in both groups is lower than previously reported. They theorize this difference could result from the use of a different diagnostic test (in this case, polymerase chain reaction [PCR]) and the inclusion of non-oncogenic strains of the virus in other studies.
The researchers also advocate caution when interpreting the correlation between hr-HPV and AIN2+, since HRA was only performed in patients with abnormal screening tests. Still, they consider HRA a cost-effective strategy for anal cancer screening among HIV-infected MSM.
For non-MSM patients, Gandra and his group conclude that the screening test used in the study, Hybrid Capture 2 (HC-2), merits further exploration.
Their final conclusion is that the prevalence of abnormal AC and hr-HPV infection in HIV-infected MSW and women warrants more study and a broadening of routine anal cancer screening for all HIV patients, not only MSM.
Fred Furtado is a science writer based in Rio de Janeiro, Brazil.
Follow Fred on Twitter: @Patchlord.