Survival analysis of CLL/SLL patients with Richter’s transformation to DLBCL: An analysis of the SEER database.

Abstract

e20024 Background: Richter's transformation (RT) from Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (CLL/SLL) to a Diffuse Large B-Cell Lymphoma (DLBCL) is a rare complication with an estimated incidence of less than 5% and a poor prognosis based on small retrospective studies. Large studies investigating the natural history and patient outcomes with this entity of DLBCL are lacking, and prospective data on the best treatment option are scarce and limited by rarity of this condition. Methods: We queried the US Surveillance, Epidemiology, and End Results (SEER) 18 database for patients sequentially diagnosed with CLL/SLL followed by DLBCL from January 2000 to December 2016 with a cutoff latency of 2 months. Data obtained included patient demographics, history of treatment for CLL/SLL, overall survival (OS) after DLBCL diagnosis and latency period between CLL/SLL and DLBCL diagnoses. For comparison, SEER data was obtained for patients with de novo DLBCL and for CLL/SLL patients without RT in the same date range. Survival was estimated by Kaplan Meier method and log rank test was used to compare outcomes. Results: 471 patients who developed RT to DLBCL and 98425 patients with de novo DLBCL were identified. The median time for developing RT to DLBCL was 54 months. Median OS was worse for DLBCL arising from RT compared to de novo DLBCL (64 months versus 10 months, p < 0.0001). In patients with RT to DLBCL, no statistically significant difference in median OS was seen in patients who received treatment for CLL/SLL versus those assigned as No/Unknown treatment status (p = 0.51). In patients with CLL/SLL in the specified time period; median OS was significantly lower for those who developed RT to DLBCL compared to those who did not (91 months versus 100 months, p = 0.0012). Conclusions: DLBCL arising from RT in CLL/SLL patients is not necessarily a late complication. Prognosis is dismal with a trend towards a poor OS in the subset of patients with pretreated CLL/SLL. This large population study correlates with prior reports and highlights the need for prospective data to inform prognosis and treatment decisions.