BACKGROUND: We analysed associations between immunodeficiency and cancer incidence in a nationwide cohort of people living with the human immunodeficiency virus (HIV) in South Africa.
METHODS: We used data from the South African HIV Cancer Match study built on HIV-related laboratory measurements from the National Health Laboratory Services and cancer records from the National Cancer Registry. We evaluated associations between time-updated CD4 cell count and cancer incidence rates using Cox proportional hazards models. We reported adjusted hazard ratios (aHR) over a grid of CD4 values and estimated the aHR per 100 CD4 cells/µl decrease.
RESULTS: Of 3,532,266 people living with HIV (PLWH), 15,078 developed cancer. The most common cancers were cervical cancer (4,150 cases), Kaposi sarcoma (2,262 cases), and non-Hodgkin lymphoma (1,060 cases). The association between lower CD4 cell count and higher cancer incidence rates was strongest for conjunctival cancer (aHR per 100 CD4 cells/µl decrease: 1.46, 95% confidence interval [CI] 1.38-1.54), Kaposi sarcoma (aHR 1.23, 95% CI 1.20-1.26), and non-Hodgkin lymphoma (aHR 1.18, 95% CI 1.14-1.22). Among infection-unrelated cancers, lower CD4 cell counts were associated with higher incidence rates of oesophageal cancer (aHR 1.06, 95 CI 1.00-1.11), but not breast, lung, or prostate cancer.
CONCLUSIONS: Lower CD4 cell counts were associated with an increased risk of developing various infection-related cancers among PLWH. Reducing HIV-induced immunodeficiency may be a potent cancer prevention strategy among PLWH in sub-Saharan Africa, a region heavily burdened by cancers attributable to infections.