Immediate Access to ART Reduces Infection-Related Cancer in HIV

Immediately starting patients on combination antiretroviral therapy (cART) reduced the risk of infection-related cancer in patients with human immunodeficiency virus (HIV), particularly cases of Kaposi sarcoma and non-Hodgkin lymphoma, according to a study published in Clinical Infectious Diseases.¹

The 4685 participants from 35 countries enrolled in the START trial (NCT00867048) were randomly assigned to either receive cART immediately or after a deferral period. All participants had a CD4 count over 500 cells/mm³ and were permitted to remain in the deferred arm until their CD4 counts dropped below 350 cells/mm³ or they developed an AIDS defining illness.

The researchers noted that there were 14 cancers in the immediate cART arm (6 infection-related and 8 infection-unrelated) and 39 cancers in the deferred arm (23 infection-relation and 16 infection-unrelated). Cancer due to the following infectious agents were defined as infection-related cancer: human herpesvirus 8 (Kaposi sarcoma), Epstein-Barr virus (non-Hodgkin lymphoma, Hodgkin lymphoma), and human papillomavirus (anal cancer, cervical cancer).  Any malignancies outside of these were classified as infection-unrelated cancer.

Immediately beginning antiretroviral therapy reduced the risk of infection-related cancer by 74% (hazard ratio [HR] = 0.26, 95% confidence interval [CI] 0.11 to 0.64, P =.003) and infection-unrelated cancer by 51% (95% CI 0.21 to 1.15, P =.103). Older age, higher body mass index, low-middle income region, HIV RNA level, and baseline CD8 count were independent predictors of infection-related cancer.  Older age and baseline CD8 count were the only independent predictors of infection-unrelated cancer.

“These findings suggest that the benefit of immediate cART in reducing cancer goes beyond HIV RNA suppression and immune status as assessed by CD4 counts and seems likely to be also mediated by other mechanisms impacting co-infections with pro-oncogenic virus and immune surveillance,” the researchers wrote.

The following were listed as important limitations in their findings:

• This data was derived from post hoc analysis with a limited follow-up period.
• Definitive infectious origin was not established by tissue analysis.
• The number of cancer events was relatively small.

Reference

1.      Borges AH, Neuhaus J, Babiker AG, et al for the INSIGHT START Study Group. Immediate antiretroviral therapy reduces risk of infection-related cancer during early HIV infection. Clin Infect Dis. 2016; doi: 10.1093/cid/ciw62.