Abstract 6750: Primary effusion lymphoma descriptors and clinicopathologic determinants of survival: Analysis of a pooled database
Authors: Gupta Supriya , Graham Christopher , Haddad Philip A. 
Published: April 2023

Abstract
Background Primary effusion lymphoma (PEL) is a rare and aggressive type of B-cell non-Hodgkin lymphoma presenting primarily as lymphomatous effusions in body cavities and less often as solid extracavitary masses. It is typically associated with human herpesvirus 8 (HHV8) infection and occasionally with Epstein-Barr virus (EBV) co-infection. It is commonly seen in immunocompromised states, such as human immunodeficiency virus (HIV) infection, organ transplantation, immunosuppressive therapy, or advanced age. Due to our limited understanding of this disease, we conducted this pooled database analysis to delineate key clinicopathological characteristics, prognostic indicators, and treatment modalities that affect survival in this rare and unique lymphoma subtype.
Methods To study the demographic characteristics, molecular and immunohistochemical signatures, therapeutic interventions, survival, and prognostic factors, we compiled a pooled database of 303 cases of PEL. All cases with an unequivocal expression of CD19 and CD20 expression were excluded. Kaplan-Meier survival curves were constructed. Cox proportional hazards model and Log-rank tests were used to assess the influence of demographic and clinicopathologic factors on overall survival (OS).
Result A total of 304 patients with confirmed PEL were identified. The median age was 49, with a peak incidence between 42 and 56 years. There was a male preponderance with M:F of 10. The majority (71%) was associated with HIV infection, with a median CD4 count of 108. Sixty-eight percent were cavitary with the pleural, pericardial, and peritoneal cavities involved in 56%, 20%, and 30%. The median duration of symptoms before diagnosis was 1.5 months. Patients presented with constitutional symptoms, hepatosplenomegaly, lymphadenopathy, and bone marrow involvement in 31%, 10%, 20%, and 16%. The median OS of the whole group was 6.5 months. Presentation with constitutional symptoms (p=0.026), extracavitary/solid tumors (p=0.03), and normal platelet counts (p=0.04) were associated with better median OS. Cavitary disease with effusions restricted to the thoracic cavity had also better median OS (p&lt;0.0001). PEL occurrence in the context of immunosuppression due to transplantation had poor median OS (p=0.004). While having Kaposi sarcoma tended to impact OS negatively (p=0.08), Castleman’s disease did not. Compared to no treatment, combination chemotherapy alone, chemotherapy with anti-retroviral therapy, and stem cell transplant were statistically superior with a median OS of 1.5, 8, 30, and 16 months, respectively (p&lt;0.0001).
Conclusion This study presents updated clinicopathologic data from a pooled cohort of patients with PEL. It identifies the type of clinical setting contributing to immunodeficiency, disease presentation, the primary location of cavitary disease, and treatment approach as key determinants of OS.
Citation Format: Supriya Gupta, Christopher Graham, Philip A. Haddad. Primary effusion lymphoma descriptors and clinicopathologic determinants of survival: Analysis of a pooled database. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6750.