Anal Cancer Screening Uncommon Among HIV-Positive MSM in Care
Anal cancer screening was uncommon -- at only 11% -- among a study of HIV-positive men who have sex with men (MSM) receiving HIV care, despite this community being at a significantly higher risk for anal cancer, according to a study presented by Mark S. Freedman, M.P.H., at IDWeek 2016 in New Orleans.
Anal pap testing is a non-invasive method of screening for anal cancer, particularly among those who may be at a higher risk. No studies show strong data to support the use of an anal cancer-screening program, Freedman noted. Furthermore, there are no population-based estimates on anal pap testing among MSM living with HIV, and these data are needed to better understand screening practices.
The incidence of anal cancer among HIV-positive men who have sex with men has increased over the last 30 years, with 83% of excess anal cancers occurring among this population. What's more alarming, the rates of anal cancer are 37 times higher among HIV-positive MSM than HIV-negative MSM. Despite these numbers, there are no national guidelines recommending anal cancer screening for this group by either anal cytology or high-resolution anoscopy (HRA), according to Freedman. Part of the hesitation is because previous studies show mixed results on the clinical benefit, cost-effectiveness and reduction in morbidity and mortality of anal cancer from using anal cytology as a primary screening tool. Moreover, not many providers are trained to perform HRA.
The study sought to estimate the prevalence of anal pap testing among HIV-positive MSM receiving HIV care and to answer the following questions:
- Are there differences among HIV-positive MSM who do get tested?
- Are HIV-positive MSM with established risk behaviors for anal cancers being tested?
- Are there provider factors that are associated with testing?
The researchers used 2009-2012 data from the Medical Monitoring Project (MMP), which is a surveillance system describing the clinical and behavioral characteristics of adults receiving HIV medical care in the United States. During this time, the MMP collected data by conducting in-person or telephone interviews and by abstracting data from medical records from 8,514 HIV-positive MSM in care. The response rates varied. Among facilities, the response rate was between 76% and 85%; and among patients, the response rate was between 49% and 53%.
Receipt of anal pap testing was defined as having medical record documentation of an anal pap test with valid results. Participants were asked whether they had been tested within the year prior to the interview.
Overall, the prevalence of anal pap testing among study participants was 11%, with the other 89% either not having tested or not having documented testing with results. Looking at select characteristics of the study population, the researchers found that African Americans were less likely to test, with only 7% having done so, compared with 13% of white participants (P < .0001).
Some of the known anal cancer risk factors were associated with anal pap testing. Those who reported any receptive anal sex were more likely to test, at 13%, compared with 10% of those who did not report receptive anal sex (P < .0001). Interestingly, current smokers were less likely to test, at 10%, versus 12% of those who did not smoke (P = .006).
Among the subgroup of 1,234 study participants who had been tested for sexually transmitted infections (STIs), those who had been diagnosed with an STI were more likely to get an anal pap test, at 19%, compared with 14% who were not diagnosed with an STI (P = .1).
Freedman pointed out that some of these behaviors may have been underreported during interviews because of social desirability bias, which is a limitation of self-reported information.
The study found no statistically significant differences in testing prevalence based on health care coverage status or time since HIV diagnosis.
In terms of provider factors associated with anal pap testing, participants who received care from facilities that had a patient load (estimated number of patients during the first four months of each year) over 400 were more likely to get tested, at 14%, compared with 4% of those who received care from facilities with a patient load below 50 (P < .0001). Additionally, participants who were tested for any STIs were more likely to receive an anal pap test, at 14%, versus 7% of those who were not given STI testing (P < .0001).
The researchers conclude that the adoption of anal cancer screening guidelines may reduce morbidity and mortality, particularly because anal pap testing in higher risk groups, such as HIV-positive MSM, has been shown to be feasible and acceptable. By comparison, the screening guidelines for cervical cancer, which is similar to anal cancer, have reduced morbidity and mortality in HIV-positive women, Freedman concluded.