Results of a study published in Clinical Infectious Diseases found that rates of infection-unrelated cancers were higher than infection-related cancers among older adults with HIV infection.
Data for this study were sourced from the South African HIV Cancer Match (SAM) study, a nationwide cohort conducted among individuals with HIV infection. Using data collected between 2004 and 2014, infection-related and -unrelated cancer rates were modeled as a function of age among HIV-positive participants.
The study population comprised 5,222,827 participants (women, 69%), representing 15,376,297 person-years of follow-up.
A total of 29,580 participants developed cancer, of whom 19,749 had infection-related and 8764 had infection-unrelated cancer. The most common cancers were cervical cancer (n=7418), Kaposi sarcoma (n=6380), and breast cancer (n=2748).
Among younger (age, <40 years) men and women, the incidence of infection-related cancers was significantly higher than infection-unrelated cancers. Beginning at 40 years of age, the incidence of infection-unrelated cancers began to increase until surpassing the incidence of infection-related cancers by 55 years of age.
Significant age- and sex-based interactions were observed for all infection-related cancers, with the exception of bladder cancer. No such interactions were observed for infection-unrelated cancers.
Although the incident rates for the majority of infection-unrelated cancers began to increase at 40 years of age, breast cancer began to increase at 30 years. In both HIV-positive men and women, leukemia incidence was lowest at 37 years of age. For colorectal, lung, esophageal, and prostate cancers, incidence rates were stable among older participants.
Significant interactions between age and CD4+ cell count were observed for non-Hodgkin lymphoma, non-AIDS defining human papillomavirus-related cancers, and stomach cancer, in which lower CD4+ cell counts were associated with higher cancer rates. No such interactions were observed for infection-unrelated cancers.
The results of this study may have been biased as only pathology-based cancer diagnoses were included.
“Over time, the prevention and early detection of infection-unrelated cancers will become increasingly important to reduce cancer-related morbidity and mortality among PWH [people with HIV infection],” the researchers concluded.
Ruffieuz Y, Muchengeti M, Olago V, et al. Age and cancer incidence in 5.2 million people with HIV: the South African HIV Cancer Match study. Clin Infect Dis. Published online December 3, 2022. doi:10.1093/cid/ciac925