Characteristics and outcomes of plasmablastic lymphoma in a predominantly Hispanic population.

Abstract

e19079 Background: Plasmablastic lymphoma (PBL) is a rare subtype of diffuse large B-cell lymphoma and is frequently associated with immunosuppression. PBL displays immunoblastic morphology and a plasma cell immunophenotype. Data regarding patient characteristics, outcomes, and optimal treatment for this disease is limited. The reported prognosis of patients with PBL has been historically poor, with median overall survival ranging from 6 to 18 months. A recent publication of the SEER/NCDB database found a significantly improved OS in the Hispanic population (HR 0.7, p=0.014). This study investigates demographic, treatment, and survival outcomes for a primarily Hispanic PBL population. Methods: We identified 42 cases of pathologically confirmed PBL at two high volume tertiary care centers in Southern California between March 2010 and June 2023. Chart review was used to collect data on clinical presentation, treatment, and outcomes. Results: Median age of patients at diagnosis was 46 years (range 17-91 years) and 90% were male. Hispanic patients represented 81% of the total cohort. Predisposing immunosuppression was identified in 60%, and 50% of the total cohort were HIV-positive. Pathologic analysis showed EBV positivity by EBER in situ hybridization in 67%. 76% of patients presented with advanced disease (Stage III/IV). The most common regimens were EPOCH (27%) and V-EPOCH (49%). Response rates and CR rates were 63% and 50% respectively. Median follow-up was 10.5 months. OS was 72% at 1-year and 60% at 2-years. Conclusions: Our cohort demonstrated a 1-year OS of 72% compared to the 56% 1-year OS for PBLs in the SEER/NCDB database. There was no statistically significant difference in survival between the Hispanic and Non-Hispanic cohorts in our study. However, this is likely due to the small sample size in the latter. Notably, our patient population had more advanced disease at presentation (76% Stage III/IV) than the SEER/NCDB cohort (60% Stage III/IV). This improved survival is likely multifactorial, but could represent ethnic differences in PBL biology, high EBV positivity, and the frequent utilization of higher intensity regimens (EPOCH/V-EPOCH = 76%). Further studies are needed to better characterize this disease in the Hispanic population. [Table: see text]