Abstract 6751: Provisional prognostic score for primary effusion lymphoma
Authors: Haddad Philip A. , Gupta Supriya , Graham Christopher 
Published: April 2023

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. Survival remains poor, and an optimal regimen has yet to be identified. However, the disease presents a diverse spectrum of survival outcomes. We conducted this study to develop a provisional PEL prognostic score (PPS) for this rare disease.

Methods We used our constructed PEL database, which contains retrospective data on 302 cases. Such data included demographics such as sex, age, and race. It also included disease presentation symptoms, duration of symptoms before diagnosis, site(s) of the disease, blood counts, coexisting comorbidities, disease immunohistochemical and molecular phenotype, types of treatment, and survival outcomes. Of the 302 cases, only 238 had complete survival and outcomes data, the sample chosen for this study. Cox proportional-hazards model and Log-rank tests were used to assess the influence of clinicopathologic factors on overall survival (OS). Due to the relatively small training cohort, we included factors that statistically impacted OS and those that numerically trended that way.

Results The median OS of the cohort was 6.5 months. The following dichotomous variables were identified as impactful prognostic factors in this cohort: the absence of constitutional symptoms (5 vs. 18 months), cavitary effusion disease (6 vs. 66 months), peritoneal cavity disease (3.5 vs. 11 months), transplant context (4 vs. 7 months), male sex (6 vs. 40 months), and detectable HHV8 viremia (7 vs. 66 months). A prognostic model was devised using these variables to identify different levels of risk. Each variable was assigned a score of 1 when present, except for peritoneal cavity disease and transplant context, which were assigned 2 points as they had the highest hazard ratio of all the other variables. In this exploratory cohort, low risk was assigned a score of 0-1, intermediate risk a score of 2-3, and high risk a score of 4-8. This prognostic score system led to our cohort's most optimal risk discriminatory model, where low, intermediate, and high risk had a median OS of 66, 28, and 4 months, respectively (p&lt;0.0001).

Conclusion This PPS is a promising new tool for risk-stratifying patients with PEL. However, it still needs prospective validation.

Citation Format: Philip A. Haddad, Supriya Gupta, Christopher Graham. Provisional prognostic score for primary effusion lymphoma. [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 6751.