Abstract 1913: Population-based analysis of primary mediastinal B-cell lymphoma: a look at Hispanic outcomes
Authors: Boyle Lauren Diaz , Toro-Velez Esteban , Duque Adolfo Enrique Diaz 
Published: April 2023

Abstract
Background: Primary Mediastinal B-cell Lymphoma (PMBL) is a rare, aggressive Non-Hodgkin Lymphoma (NHL) accounting for approximately 2-5% of all NHL (PMID: 34330673). Due to its rarity, there is scarce literature on the demographic features of PMBL. Moreover, there is little to no research on outcomes of ethnic minority groups, particularly in Hispanics (HI) (PMID: 27399089.) Thus, there is a need for further investigation of disease characteristics to advance treatment options for the future. This is a national scale population-based analysis examining disparities in HI vs Non-Hispanics (NH) and its impact on survival outcomes in patients with PMBL.
Material and Methods: Data was analyzed on PBML patients in the United States reported to the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2018. SEER contains the most comprehensive population-based cancer information in the U.S., covering approximately 27% of the total US population, and up to 36% of Hispanics alone. Racial groups analyzed included non-Hispanic whites, Hispanic whites, blacks, and Asians/PIs (Pacific Islanders). Patient characteristics, age-adjusted incidence rate, and survival rate were compared across ethnic groups, Hispanics (HI) vs Non-Hispanics (NH). Stratification by age, gender, and stage at diagnosis was considered. Kaplan-Meier and Cox regression analyses were used to compare overall survival (OS) between HI and NH. Multivariate analysis and propensity score matching were performed with adjustment for age, stage and B-symptoms.
Results: Of 1,014 PMBL patients, 15% were HI, and 85% were NH. PMBL affects mostly women in both HI and NH (66% and 60% p=0.215). HI were diagnosed at a younger median age, 30 y.o vs 36 y.o (p=0.001), compared to NH. The majority of HI and NH were diagnosed under 40 years old (p=0.010). Both groups were mostly diagnosed between 2015-2018 (44% vs 41%) (p=0.768). The majority of both groups did not receive radiation, however it was noted that HI received less radiation compared to NH (72% vs 66%) (p=0.180). The median survival time was not reached indicating a favorable prognosis. On survival analysis; the survival probability of HI vs NH at 2 years was 0.87 vs 0.86, at 5 years 0.85 vs 0.85, and 10 years 0.83 vs 0.82. and there was not an OS difference favoring HI/NH (p = 0.94). On multivariate analysis, when adjusting for age, those who were older than 80 y.o and between 60 to 80 y.o, had worse OS compared to those younger than 60 y.o with HR 9.3 (95% CI: 4.3 - 20) and 8.8 (95% CI: 4 - 19).
Conclusions: Our study analysis shows that the demographic variables between HI and NH were generally homogenous. In patients with PMBL, HI were diagnosed younger compared to their NH counterparts, however this did not affect OS. In conclusion, HI and NH patients with PMBL had similar treatment and outcomes showing that, when there is equity in health, favorable prognosis is possible with the current standard of care.
Citation Format: Lauren Diaz Boyle, Esteban Toro-Velez, Adolfo Enrique Diaz Duque. Population-based analysis of primary mediastinal B-cell lymphoma: a look at Hispanic outcomes [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 1913.