Immediate initiation of combination ART can reduce the risk for infection-related cancers in newly diagnosed HIV patients, a recent analysis indicated.
“According to recent estimates, up to 40% of cancer cases among HIV-positive persons in the United States are infection-related; an attributable fraction 10 times as high as in the general population,” Álvaro H. Borges, MD, PhD, clinical associate professor at the University of Copenhagen, Denmark, and colleagues wrote. “HIV-positive persons also have an increased risk of infection-unrelated cancer. Reduced control of oncogenic viruses and impaired immune surveillance of malignant cells may facilitate carcinogenesis during HIV infection.”
To determine the impact of ART on these cancers, Borges and colleagues re-examined data from the Strategic Timing of Antiretroviral Treatment (START) trial. In the study, researchers randomly assigned 4,685 HIV patients from 35 countries to receive immediate or deferred combination ART. After a 3-year follow-up, they found improved CD4 counts among those given prompt therapy. Borges and colleagues identified cancer events among START participants, categorized each as infection-related and infection-unrelated, and they calculated the impact of ART initiation on cancer incidence.
The researchers identified 14 cancer events among HIV patients who received immediate ART, and 39 among those with delayed treatment. Patients receiving immediate ART were less likely to develop infection-related cancers (HR = 0.26; 95% CI, 0.11-0.64), although this association was weakened for infection-unrelated cancers (HR = 0.49; 95% CI, 0.21-1.15). Patients in the deferred group were more likely to develop cancer after 1 year of follow-up, whereas annual incidence in the immediate ART group remained stable. After adjustment, the researchers identified older age, higher BMI, residence in a low-middle income region, baseline HIV RNA and baseline CD8 count as independent predictors of infection-related cancer; older age and baseline CD8 count were the only predictors of infection-unrelated cancer.
The researchers noted that immediate ART’s protective effect was primarily driven by a reduction in cases of Kaposi sarcoma and non-Hodgkin’s lymphoma. Further, their adjustments of the analysis model for CD4 counts did not impact the effect of immediate ART on infection-related cancers, and adjustments for HIV RNA levels played only a minor effect.
“These findings suggest that the benefit of immediate [combination ART] in reducing cancer goes beyond HIV RNA suppression and immune status as assessed by CD4 counts and seems to likely to be also mediated by other mechanisms impacting coinfections with pro-oncogenic virus and immune surveillance,” the researchers wrote. “Further research is needed to identify mediators of the benefit of immediate [combination ART] initiation in reducing cancer risk.” – by Dave Muoio
Disclosure: Borges reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.