LAUSR

Background Diffuse large B cell lymphoma (DLBCL) is the most common histological subtype of non-Hodgkin lymphoma (NHL), accounting for 25% of NHL subtypes. Usually associated with classic B-symptoms, such as fever, weight loss and night sweats in about 30% of patients, accompanied with elevated lactate dehydrogenase. Approximately in 25-40% of DLBCL cases, the disease arises from extra-nodal sites, such as stomach/gastrointestinal tract. Differences in clinical outcomes between extra-nodal and nodal site involvement suggest that both types should be considered as different entities. Our study aims to identify the role of primary nodal site as predictive tool for clinical and survival outcomes in patients with DLBCL. Methods Our study was based on data from the Surveillance, Epidemiology, and End Results program database. We used the Kaplan-Meier curve, log-rank test, and Cox proportional hazard regression models to examine predictors affecting the DLBCL survival. We used the multi-variable analysis to get overall survival (OS) as well as the disease-specific survival (DSS). Results From a total of 34,231 DLBCL patients were identified. The mean age was 61.3 years. The majority had multiple regions (M) lymph nodes (LNs) (18,044, 52.7%) followed by head, face and neck (HFN), intra-abdominal, intra-thoracic, axilla or arm (AA), inguinal or leg (IL) then pelvic LNs. Moreover, male, unmarried, black or Asian/Pacific Islander, older patients, advanced stages, and patients did not receive radiation and/or surgery were associated with a worse survival. We found a mean survival time of 61.07 months with OS and DSS of 39.1/54.1% only. The multiple regions, intra-abdominal, intrathoracic LNs were significantly associated with a worse survival. Conclusions DLBCL incidence has increased in the recent years. The multiple regions, intra-abdominal, intrathoracic LNs were significantly associated with a worse survival, suggesting that DLBCL nodal primary site can serve as a simple yet prognostic tool. Hence, we strongly encourage future studies to compare DLBCL patients9 survival affected by these aggressive primary sites with other unfavorable predictors in IPI. Moreover, biomarkers, within these aggressive sites, may demonstrate their aggressive behaviors. Furthermore, more studies need to shed the light on the biological theory beyond these aggressive primary sites and to validate its reliability. Citation Format: Mohamed Gomaa Kamel, Fatma A. Abd-Elhay, Sara Morsy, Amr E. El-Qushayri, Khaled M. Elhusseiny, Muhammed K. Elfaituri, Ahmed M. Kamel, Sherief Ghozy, Nourin A. Sherif, Nguyen Tien Huy. The role of primary lymph node sites in survival and mortality prediction in DLBCL: A SEER population-based retrospective study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2215.