Cancer: the effects of HIV and antiretroviral therapy, and implications for early antiretroviral therapy initiation

Purpose of review As the immune status of people with HIV has improved, non-AIDS-defining malignancies have become proportionately much more important as causes of morbidity and mortality in this population. This review examines whether the incidence and mortality from cancer is associated with impaired immunity and whether effective antiretroviral therapy (ART) may reduce risk of cancer. Recent findings The incidence of non-Hodgkin's lymphoma and Kaposi's sarcoma is substantially and rapidly reduced by effective ART. Nevertheless, the incidence of each appears to remain raised somewhat in people receiving ART. Study of other cancer types has been hampered by their relatively infrequent occurrence, but there is emerging evidence that a large range of around 20 cancer types are associated with immune deficiency. There are insufficient data on individual cancer types to definitively conclude whether ART may decrease risk, but emerging data from cohort studies suggest that ART does reduce the overall risk of cancer. Summary Cancer is increasingly being recognized as an important cause of morbidity and mortality in people with HIV and at least some of the excess risk in people with HIV may be reversible by earlier ART. More data are needed from large-scale prospective cohorts and from randomized controlled trials of ART therapy on current CD4 cell count as a predictor of cancer risk.