Richter Transformation of Chronic Lymphocytic Leukemia: Incidence, Risk Factors and Outcome

Abstract

Richter transformation (RT) is a rare complication of chronic lymphocytic leukemia (CLL). There is little information in the literature about its risk and outcome. In this study we assessed the incidence, presenting characteristics and outcomes of patients (pts) with CLL who developed RT. An electronic database search of pts with CLL who presented at St Paul's Hospital between 1969 and 2007 was performed. Among 465 pts with CLL, 24 pts (5%) developed RT. Presenting features included B-symptoms (17%), lymph node enlargement (58%), progressive cytopenia (29%), hypercalcemia (4%), and spleno/hematomegaly (13%). The median age at diagnosis of CLL and RT were 64 y (range 33–80 y) and 67 y (range 48–81 y) respectively. The median time to transformation from CLL diagnosis was 61 months (range 1–257 m). Twenty one patients (88%) had been previously treated for CLL. Seventeen patients (71%) had received >1 prior therapy. The median lymphocyte count at diagnosis was 12 ×109/L (range 4–120 ×109/L). Six patients (25%) are still alive with a median follow up of 38 m (range: 3–66 m). The only predictive factor for better survival post-transformation on univariate analysis was age of less than 60 y at CLL diagnosis (p=0.01). Other factors such as CLL Rai stage, lymphocyte count at diagnosis were not predictive for survival. This group of patients was compared with randomly selected group of patients with CLL but did not have RT. The baseline characteristics of the groups are presented in the table. No significant differences were found between the two groups in terms of gender, age at diagnosis, Rai stage or median lymphocyte count at diagnosis. The 5 and 10 year OS for the RT group were 76% and 39% compared to 93% and 84% for the CLL group (p= 0.002), respectively. In summary, RT significantly shortens the survival of CLL patients. There were no obvious predictive factors for RT in CLL pts at diagnosis.Table: Baseline characteristics of Richter and CLL groups.ParameterRichter group (%)CLL group (%)P valueNumber2437Sex: M/F (ratio)16/8 (2:1)22/15 (1.5:1)0.052Age at Diagnosis: Median (range)64 (33–80)60 (37–85)0.6Rai stage at diagnosis: 0, 1+2, 3+47, 16,1 (29, 67, 4)23, 14, 0 (62, 38, 0)0.3Median lymphocyte count at diagnosis (range)12 ×109/1 (4–120)8 × 109/1 (5–394)0.056 [Display omitted]