Who’s most at risk of getting Kaposi sarcoma? New research gives insights
People who had low recent CD4 counts, high recent viral loads, or who had higher average viral loads over time had the highest risk of developing Kaposi sarcoma, according to a study published this month in JAIDS. By analyzing medical data from thousands of people living with HIV across many years, a team of researchers were able to develop a mathematical model of factors independently associated with Kaposi sarcoma (KS, an opportunistic cancer characteristic of AIDS).
They found that a person’s most recent CD4 count, their most recent viral load count, and a cumulative measure of viral load over time were independent risk factors for developing KS. Previous research has identified associations between CD4 count, viral load and KS risk, but this is one of the only studies to make conclusions about risk based on a comprehensive examination of both recent and cumulative measures and a relatively large sample size.
The researchers included data from 77,696 people from the U.S. and Canada in the North American AIDS Cohort Collaboration on Research and Design, who were followed between 1996 and 2009. The majority of people in the study were male (85%).
People with recent CD4 counts less than 50 cells/uL were 12 times more likely to develop KS than people with CD4 counts equal to or over 500. People with recent viral loads over 100,000 copies/mL were about four times more likely to develop KS than people with viral loads less than or equal to 500 copies/mL. People with an average viral load over 100,000 copies/mL were two and a half times more likely to develop KS than people with an average viral load less than 500 copies/mL.
“The most interesting—and most novel—finding from the study was the cumulative viral load finding,” said lead author Robert Dubrow, MD, PhD. “This isn’t something that’s been found before. For people living with HIV—and in terms of patient care—it speaks to the importance of people starting HIV treatment right away. This minimizes the amount of time they spend with an elevated viral load and therefore, our results indicate, should decrease their risk of KS.”
In addition to reducing risk for KS, early antiretroviral therapy increases life span and reduces the risk of developing other AIDS-related infections like tuberculosis and non-AIDS related conditions like cancer.
Many people know KS as the AIDS-related cancer that produces red, purple or brown lesions on the skin. Currently in the U.S., about 2,500 cases of KS occur yearly. At the beginning of the AIDS epidemic nearly half of men who have sex with men with AIDS developed KS. People living with HIV, who are also infected with the KS-causing virus (KSHV), may develop KS as an opportunistic cancer when HIV has sufficiently damaged the immune system. (The prevalence of KSHV among HIV-positive men who have sex with men is between 30% and 60%.)
An outstanding question the study did not answer, said Dubrow, is how long the effect of having an elevated cumulative viral load raises KS risk after a person suppresses their viral load.
“In other words, if a person had an elevated viral load for seven or eight years before they were diagnosed and treated with antiretroviral therapy, but then suppressed their viral load, how long might this person still be at an elevated risk of developing KS? If they’ve been on ART and been virally suppressed for five years, are they still at elevated KS risk because of that period in the past? Or does that effect dissipate over time?”
Future research is needed to answer these questions, and to replicate the findings of the current study, said Dubrow. “This was a relatively novel finding about cumulative viral load effects [on KS risk], and it’s important for other investigators to try to confirm this.”
Read more about the importance of starting HIV therapy early in this BETA article by Joanna Eveland, MD, and how San Francisco’s RAPID program is ensuring that people newly diagnosed with HIV are immediately linked to care and are able to reach viral suppression more quickly.
Dubrow, R. and colleagues. Association of CD4+ T-cell Count, HIV-1 RNA Viral Load, and Antiretroviral Therapy With Kaposi Sarcoma Risk Among HIV-infected Persons in the United States and Canada. JAIDS, August, 2017.