Pancreatic Diffuse Large B-cell Lymphoma in the US Population

Background: Pancreatic lymphomas (PLs) represent <2% of all lymphomas and <0.5% of all pancreatic neoplasms. An accurate histologic diagnosis of PL is needed to predict prognosis and adequately treat the patient. This study aims to investigate the demographic, clinical, and pathological factors affecting the prognosis and survival of pancreatic diffuse large B-cell lymphoma (DLBCL). Methods: Demographic and clinical data from 493 cases of DLBCL of the pancreas were identified between 2000 and 2018 using the Surveillance, Epidemiology, and End Results (SEER) database. Results: The most common age group was between the ages of 70 and 79 years (27.0%). While 44% of cases involved distant sites (a proxy for secondary pancreatic DLBCL), regional and localized involvement was seen in 33%, with the most common cause of death being a primary pancreatic DLBCL. Most patients (71%) received only chemotherapy (systemic therapy). The overall five-year observed survival was 46% (95% CI, 43.5-48.3). The one-year and five-year survival with chemotherapy only was 68% (95% CI, 65.3-70.3) and 48% (95% CI, 44.7-50.5), respectively. The one-year and five-year survival with surgery and chemotherapy was 96% (95% CI, 91.3-99.9) and 80% (95% CI, 71.4-89.2), respectively. Surgery with chemotherapy (HR: 0.397 (95% CI, 0.197-0.803), p = 0.010) were both positive predictors in survival prognosis. Multivariable analysis identified age >55 years (HR: 2.475 (95% CI, 1.770-3.461), p < 0.001), distant stage (HR: 6.894 (95% CI, 4.121-11.535), p < 0.001), and undergoing no surgery (HR: 2.610 (95% CI, 1.307-5.215), p = 0.007) as negative predictors for survival. Conclusion: PLs are rare malignant pancreatic neoplasms with DLBCL being the most common histological subtype. An accurate and timely diagnosis of pancreatic DLBCL is necessary to implement effective treatments and reduce mortality. Systemic therapy (chemotherapy) with or without surgical therapy improved survival. Increased age and regional and distant spread negatively impacted survival.