Unstaged Diffuse Large B-Cell Lymphoma in the United States: Predictors and Patient Outcomes

Background: Treatment and prognosis of diffuse large B-cell lymphoma (DLBCL) depends on the stage of lymphoma. We conducted this study to examine unstaged DLBCL in the United States. Materials and Methods: We used Surveillance Epidemiology and End Result (SEER) 18 registries to select patients with DLBCL diagnosed during January 2000 to December 2012. Limited regional distant Summary stage 2000 was used to determine stage of the disease as localized, regional, distant or unstaged. We used logistic regression to investigate factors associated with unstaged DLBCL. Cox proportional hazards model was used to compare survival outcomes. Results: Among 67,765 patients, disease in 3,194 (4.71%) was unstaged. Age (60+years), non-African American, not married marital status, metropolitan residence, median household income >$50,000, lymph node as the primary site and those with other primary malignancies before diagnosis of DLBCL were the factors associated with cases being unstaged. The 5-year relative survival rate for patients with unstaged DLBCL was inferior to that of those with localized and regional disease, and superior to that of those with distant disease (hazard ratios of 0.58, 0.66 and 1.24 for localized, regional and distant disease, respectively, when compared to unstaged cases). Conclusion: Several factors are associated with higher risk of unstaged DLBCL. Patients with unstaged DLBC had significantly inferior survival rates compared to patients with localized and regional stage.