A single institutional experience of 261 patients with large granular lymphocytic leukemia (LGLL).

Abstract

7555 Background: LGLL is a rare clonal lymphoproliferative disorder of post-thymic T-cell or natural killer (NK)-cell lineage associated with cytopenias, splenomegaly, autoimmune disorders, and recurrent mucocutaneous infections. Treatment is dictated by the presence of these manifestations and consists of immunosuppressive therapy. Methods: This is a retrospective analysis of clinical and laboratory features, treatment modalities, and outcomes of LGLL patients evaluated at Moffitt Cancer Center between 1995 and 2016. Continuous and categorical variables were tested via Kruskal-Wallis ANOVA and Fisher’s Exact Test. Kaplan-Meier curves were used for overall survival (OS). P-values were two-sided with significance set at < 0.05. Results: We identified 261 patients with LGLL (91.6% T, 8.4% NK). Median age was 66 years [21-90] and M:F ratio 1.2:1. Median follow up was 3.07 years [0-21.88]. 42.9% presented with anemia, 37.1% neutropenia, 30.7% thrombocytopenia, 29.1% bicytopenia and 6.9% pancytopenia. Transfusion dependence was noted in 20.3%, splenomegaly in 27.2% and bone marrow (BM) involvement in 69.3%. 24.9% had autoimmune diseases and 9.2% autoimmune cytopenias. 45.6% were observed while the remainder required at least 1 line of therapy. 5-yr and 10-yr OS were 75.0% and 63.1% respectively. There was no statistically significant difference in OS, complete response or duration of response based on first line agent (methotrexate, cyclophosphamide, cyclosporine A). However, there was a statistically significant improved partial response with methotrexate versus other therapies (p=0.01). A marginally significant association between severe anemia/transfusion dependence and poor overall response rate (p=0.075) to any therapy was noted. There was no statistically significant difference in OS based on absolute LGL count. Mean number of therapies was 1.08 (range 0-6) and was higher in those with LGL count <0.5 k/μL (p=0.0078), BM involvement (p<0.0001), and splenomegaly (p<0.0001). Conclusions: In this large retrospective study, we described the frequency of LGLL-associated manifestations and their impact on the course of LGLL. We confirmed that there is no difference in OS among first line therapies.