Abstract 6208: Impact of primary site in hepatobiliary and pancreatic lymphomas on overall survival: analysis of SEER database

Abstract Introduction: Primary hepatobiliary and pancreatic lymphomas (PHBPL) are a rare and aggressive subset of lymphomas, comprising <0.5% of pancreatic cancers and 1% of extranodal lymphomas; due to limited data on their clinicopathological features and treatment, we used the SEER database to compare overall survival (OS) of PHBPL with those of primary nodal disease. Methods: We used the SEER database to extract demographic and disease data on patients diagnosed with lymphoma from 2010-15. Primary site was classified into three categories: primary hepatic lymphoma (including biliary tract, gallbladder, liver), primary pancreatic lymphoma (including ampulla of Vater), and primary nodal lymphoma (lymph nodes and spleen). Ann Arbor stages I-II were grouped as early-stage disease, while III-IV were grouped as late-stage. Patient cases were also divided into three distinct groups based on the histologic subtype: aggressive NHL (DLBCL, Burkitt lymphoma, MCL, T-cell lymphoma), indolent NHL (FL, marginal zone lymphoma), and Hodgkin's lymphoma. Summary statistics were used to analyze demographic and disease data. Our outcome of interest was OS defined as time in months from diagnosis to death from any cause. Cox-proportional hazards models and Kaplan-Meier method were used to perform univariate analysis. Multivariate analysis was also performed to control for age, Ann Arbor stage, race, and income. Primary nodal lymphoma was the comparison group for both. Statistical significance was defined using a 95% confidence interval and a p-value < 0.05. Results: A total of 55, 115 cases were included. The most common primary disease site was primary nodal lymphoma (54, 454 cases, 98.8%) followed by primary hepatic lymphoma (435 cases, 0.79%) and primary pancreatic lymphoma (226 cases, 0.41%). The median age at diagnosis was 63 years old with majority of patients identifying as male and Caucasian (56.26% and 70.4% respectively). Late-stage lymphoma represented 62.69% of the cohort while early-stage lymphoma represented 37.31%. Primary hepatic lymphoma was associated with worse OS when compared to nodal lymphoma (HR = 2.077, p < 0.0001). This finding remained statistically significant even after controlling for age, race, income, and stage (HR = 1.836, p < 0.0001). Primary pancreatic lymphoma was also associated with worse OS (HR = 1.226, p = 0.0349). This association persisted on multivariate analysis though statistical significance was not met (HR= 1.1182, P = 0.0841). Conclusions: Hepatic and pancreatic lymphomas have respectively significantly and slightly worse OS than their nodal counterparts. This association persisted on multivariate analysis, though multivariate findings for primary pancreatic lymphoma did not meet statistical significance. These results warrant validation in future prospective studies, including those using risk-adapted approaches to guide therapeutic decisions. Citation Format: JOSEPH SPEAR, Carmen Lessani, Olivia Davis, Silas Day, Noha Soror, Taha Mahdi Salih Al-Juhaishi. Impact of primary site in hepatobiliary and pancreatic lymphomas on overall survival: analysis of SEER database [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 6208.