Background
People with HIV (PWH) have an increased risk of cancer compared to the general population, even under antiretroviral therapy (ART); however, specific data in young PWH are lacking. Aim of the study was to assess the cancer risk of PWH aged <50 years in Italy.
Methods
Observational study in the Icona cohort enrolling ART-naïve PWH. All participants <50 years at enrolment (Jan1997/Dec 2023) were included. Incident cancers (excluding non-melanoma skin cancers) were categorized as AIDS-defining (ADMs: Kaposi’s sarcoma, KS; non-Hodgkin’s lymphoma, NHL; invasive cervical cancer, ICC) or non AIDS-defining (NADM: virus and non-virus related). Standardized incidence ratios (SIRs) as risk estimate were calculated by multiplying the person-years (PYs) at risk in PWH by the corresponding specific incidence rates from all Italian cancer registries. SIRs were standardized by sex, age, residence, calendar period.
Results
14,060 PWH were included, contributing to 94,607 PYs of follow up. Overall, 78.7% were men, with a median age of 35 years (interquartile range, 29-41). Overall, 400 (2.8%) PWH developed at least one de novo cancer (229 ADMs, 177 NADMs) during follow-up. PWH had a 2.9-fold increased risk for all cancers compared with the general population (95% CI: 2.6-3.2, Table 1; SIR=3.5 in males and 1.7 in females). Significantly elevated SIRs were observed for ADMs overall (SIR=20.8) and for individual cancer: KS (SIR=186.9), NHL (SIR=6.6), and ICC (SIR=9.3). A 9.4-fold risk increase was noted for virus-related NADMs, particularly for anal cancer (SIR=71.7) and Hodgkin lymphoma (SIR=9.2). No evidence for a difference in risk was observed for non virus-related NADMs overall (SIR=0.9, 95% CI: 0.7-1.1), with decreased risks for leukaemia, bladder (SIR=0.5), skin melanoma, and thyroid cancer (SIR=0.6); a significant risk reduction was reported only for breast cancer (SIR=0.5). Conversely, a significant increased risk was observed for trachea/bronchus/lung cancer (SIR=3.2).
Conclusions
In PWH <50 years old, cancer risk is almost 3-times higher than in the comparable general population. Higher frequencies of coinfections, smoking and HIV-related chronic inflammation might explain these findings. A patient-centered approach that considers cancer risk factor common in PWH should guide the age cut-off when to start cancer screening, in order to reduce risk gap between young people with and without HIV.
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