Treating HIV early, when the immune system is stronger, lowers the risk of infection-related cancers such as Kaposi’s sarcoma (KS) and non-Hodgkin lymphoma. It is possible that early versus delayed treatment also lowers the risk of non-infection-related cancers.
The global START trial, published in 2015, included 4,685 people with HIV who started the study with more than 500 CD4 cells. They were randomized either to receive antiretroviral (ARV) treatment immediately or after their CD4s dropped below 350 or they experienced an AIDS-defining illness. The study found that immediate versus delayed HIV treatment lowered the risk of cancer by 64 percent.
Looking to parse the effect of immediate versus delayed treatment on infection-related and non-infection-related cancers, researchers conducted a subsequent analysis of the START data and published their findings in Clinical Infectious Diseases.
The infection-related cancers analyzed included KS (related to herpes), non-Hodgkin and Hodgkin lymphoma (related to Epstein-Barr virus) and anal and cervical cancer (related to human papillomavirus, or HPV). The numerous non-infection-related cancers included, among others, prostate, lung, testicular and breast cancer.
Those in the immediate treatment group experienced 14 cancers during the study follow-up period, including six infection-related and eight non-infection-related cancers. The members of the delayed treatment group experienced 39 cancers, including 23 infection-related and 16 non-infection-related cancers.
The researchers calculated that immediate HIV treatment reduced the risk of infection-related cancer by 74 percent, mostly on account of lower rates of KS and non-Hodgkin lymphoma. Immediate treatment reduced the risk of non-infection-related cancer by 51 percent. However, this latter finding was not statistically significant, meaning it may have been driven by chance.
After adjusting the data about the combined treatment groups for various factors, the study authors found that the following factors were independently associated with an increased likelihood of infection-related cancer by the following degrees: each 10 years of additional age increased the likelihood by 1.42-fold; each additional five kilograms of body weight divided by meters of height squared (greater BMI), 1.47-fold; living in a low- to middle-income region compared with a high-income region, 3.40-fold; each 10-fold greater viral load at the study’s outset, 2.01-fold; and each greater 200 CD8 cells at the study’s outset, 1.12-fold. The only factors independently associated with non-infection-related cancers were: each 10 additional years of age, 2.54-fold; higher initial CD8 count per 200 cells higher, 1.12-fold.
Adjusting the data for the most recent viral load had little impact on the apparent effect of immediate HIV treatment on infection-related cancer, but it did attenuate the apparent effect of immediate treatment on non-infection-related cancer.
To read the study abstract, click here.