Primary effusion lymphoma in people with and without HIV infection in the United States.

Objective: Primary effusion lymphoma (PEL) is a rare non-Hodgkin lymphoma (NHL) subtype caused by Kaposi sarcoma (KS) herpesvirus. We describe PEL incidence and survival in people with HIV (PWH) and people without HIV in the US.

Design: Retrospective cohort study of PEL people with and without HIV.

Methods: PEL cases were identified in the HIV/AIDS Cancer Match (HACM) Study, a linkage of population-based cancer and HIV registries in 14 US regions. PEL incidence was examined using negative binomial regression and compared with the general population using a standardized incidence ratio. Survival was evaluated using Cox proportional hazard regression.

Results: During 2001-2019, 53% of 174 PEL cases identified in HACM data were among PWH. PWH had >700-fold higher PEL incidence than the general population. Compared to PEL cases without HIV, PWH were younger (median age: 44.8 vs. 77.7 years). Among PWH, prior KS was associated with 59-fold higher PEL incidence versus those without an AIDS diagnosis. PEL comprised 1.15% of the 8010 NHLs diagnosed among PWH in HACM during 2001-2019. HIV was not associated with mortality among PEL cases. Among PWH, Burkitt lymphoma and diffuse large B-cell lymphoma exhibited similar mortality to PEL but central nervous system lymphoma mortality was worse.

Conclusions: There are two distinct subgroups of PEL cases in the US: younger patients with HIV and older patients without HIV. The proportion of PEL cases among PWH is highly disproportionate to the size of the HIV population, reflecting the greatly elevated incidence of PEL among PWH.