November 6, 2013
HIV-infected individuals rarely receive proper screening for colorectal cancer (CRC) in the U.S., making an accurate assessment of CRC prevalence extremely challenging, according to research presented at IDWeek 2013.
CRC within the HIV-infected population has not yet been explored to the same extent as a number other non-AIDS-defining cancers, such as anal cancer. Nonetheless, research has indicated a higher prevalence of CRC among people with HIV, highlighting the value of additional data exploring CRC risk and screening.
To wit, Florence Momplaisir, M.D., of Temple University Hospital in Philadelphia, and colleagues conducted a cohort study of HIV-infected patients continuously enrolled in Medicaid programs within California, Florida, New York, Ohio or Pennsylvania between 1999 and 2007. These 55,439 individuals were age- and sex-matched with 277,195 randomly sampled Medicaid enrollees in the same state. CRC screening rates were compared across groups, as were CRC diagnosis rates in 2006 specifically.
This was, as might be expected, an extremely diverse cohort. The mean age of all the patients was roughly 50; approximately a third of the patients were female; and a majority of the patients were non-white (though the HIV-infected patients were considerably less likely to be white and more likely to be black than the HIV-uninfected patients).
After adjusting for baseline comorbidities (which were much more common among the HIV-infected population) and age, Momplaisir et al found that in 2006, CRC incidence was similar between HIV-infected and HIV-uninfected Medicaid patients, though there appeared to be a non-significant trend toward greater incidence among patients with HIV. In total, 94 of the HIV-infected patients (0.2%) were diagnosed with CRC in 2006, compared to 271 of the HIV-uninfected patients (0.1%).
CRC screening, meanwhile, told a different story: The data indicated that receipt of CRC screening was less likely among HIV-infected patients (35.8%) than HIV-uninfected patients (33.7%), a relatively small but statistically significant difference, Momplaisir said.
"There's been multiple studies where ... they found, compared to HIV-negative individuals, HIV-positive individuals were significantly less likely to get colorectal cancer screening," she added. "I think there's a lot of bias, still, in that providers may think that the life expectancy of HIV-positive patients doesn't necessarily justify cancer screening." The time range of the study data corresponds with the period before research began to solidly indicate near-normal life expectancy among HIV-infected patients who receive potent antiretroviral therapy.
Of course, as this study starkly noted, CRC screening rates overall were quite low among this cohort of Medicaid enrollees, which can undermine attempts to accurately assess incidence and prevalence. Momplaisir suggested that Medicaid enrollees -- particularly those with HIV -- may be especially in danger for missed CRC screening opportunities, due at least in part to the challenges of administering the standard CRC screening method, colonoscopy.
"There are a lot of barriers, especially in the low-income community, to get that test done," Momplaisir explained. "It requires a day off of work; someone must bring you to the site to get the test done, because you can't drive back after anesthesia. ... It's possible that those factors are overamplified in the HIV population, and people are less inclined to get colorectal cancer screening."
Myles Helfand is the editorial director of TheBody.com and TheBodyPRO.com.
Follow Myles on Twitter: @MylesatTheBody.