Viral Suppression in People With HIV Associated With Reduced Cancer Risk

Long-term HIV suppression resulting from sustained treatment with antiretroviral therapy (ART) reduces the incidence of AIDS-defining cancer (ADC) and non—AIDS-defining cancer (NADC), according to study results.

With compromised immune systems, people living with HIV have higher incidence than the general population of multiple comorbidities, including both ADCs—Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer—and NADCs. According to researchers, oncogenic viruses are the cause of ADCs and most NADCs that are common among people living with HIV.

While widely known that benefits of ART include a suppressed viral load—defined as an HIV RNA level less than 500 copies/mL—there is less consensus over the relationship between sustained ART and cancer risk.

Researchers collected and observed data from the Veterans Aging Cohort Study derived from Department of Veterans Affairs (VA) databases on demographics, vital status, inpatient and outpatient encounters, pharmacy, and laboratory results. These data were linked with the VA Central Cancer Registry and the VA Corporate Data Warehouse oncology registry. Median observation time was 7.4 years for HIV-positive participants and 10.1 years for uninfected participants.

A total of 42,411 people living with HIV were identified. Of these patients, 3821 developed 4169 cases of cancer. Among 104,712 uninfected participants, 7163 developed 7879 cases of cancer. During the 343,150 person-years observed in follow-up for those with HIV, 22% were categorized as unsuppressed, 27% were categorized as early suppression, 37% categorized as long-term suppression, and 14% were categorized as unknown.

For all cancer, there was a decrease in cancer risk for people living with HIV who were in early suppression (1475 cases per 100,000 person-years), and an even larger decrease for those with long-term suppression (1155 cases per 100,000 person-years) compared to those who were unsuppressed (1748 cases per 100,00 person-years).

These decreasing rates were consistent across both ADCs and virus NADCs. For ADC, incidence rates dropped from 474 cases per 100,000 person-years in unsuppressed participants, to 211 cases per 100,000 person-years in those with early suppression, to 56 cases per 100,000 person-years in those with long-term suppression. Similarly, for virus NADCs, incidence rates dropped from 320 cases per 100,000 person-years in unsuppressed participants to 280 cases per 100,000 person-years in those with early-suppression and to 253 cases per 100,000 person-years in those with long-term suppression.

Meanwhile, for nonvirus NADCs, incidence rates were comparable in unsuppressed participants (989 cases per 100,000 person-years) and those with early suppression (980 cases per 100,000 person-years). However, the incidence rate dropped to 863 cases per 100,000 person-years in those with long-term suppression.

“Future research should extend our sensitivity analysis to examine in more detail viral suppression thresholds less than 500 copies/mL, whether cancer risk continues to decrease with longer durations of long-term suppression, and the role of CD4⁺—CD8⁺ cell count ratio,” concluded the authors of the study.

Reference:

Park L, Tate J, Sigel K, et al. Association of viral suppression with lower AIDS-defining and non-AIDS-defining cancer incidence in HIV-infected veterans: a prospective cohort study [published online June 12, 2018]. Ann Intern Med. doi: 10.7326/M16-2094.