Age and cancer incidence in 5.2 million people with HIV: the South African HIV Cancer Match study

BACKGROUND: Old age is an important risk factor for developing cancer, but few data exist on this association in people with HIV (PWH) in sub-Saharan Africa. METHODS: The South African HIV Cancer Match study is a nationwide cohort of PWH based on a linkage between HIV-related laboratory records from the National Health Laboratory Services and cancer diagnoses from the National Cancer Registry for 2004-2014. We included PWH who had HIV-related tests on separate days. Using natural splines, we modelled cancer incidence rates as a function of age. RESULTS: We included 5,222,827 PWH with 29,580 incident cancer diagnoses - most commonly cervical cancer (n = 7418), Kaposi sarcoma (n = 6380), and breast cancer (n = 2748). In young PWH, the incidence rates for infection-related cancers were substantially higher than for infection-unrelated cancers. At age 40 years, the most frequent cancer was cervical cancer in female and Kaposi sarcoma in male PWH. Thereafter, the rates of infection-unrelated cancers increased steeply, particularly among male PWH, where prostate cancer became the most frequent cancer type at older age. While Kaposi sarcoma rates peaked at 34 years (101/100,000 person-years) in male PWH, cervical cancer remained the most frequent cancer among older female PWH. CONCLUSIONS: Infection-related cancers are common in PWH in South Africa, but rates of infection-unrelated cancers overtook those of infection-related cancers after age 54 years in the overall study population. As PWH in South Africa live longer, prevention and early detection of infection-unrelated cancers becomes increasingly important. Meanwhile, control strategies for infection-related cancers, especially cervical cancer, remain essential.