Central nervous system involvement in adult acute lymphoblastic leukemia at diagnosis and/or at first relapse: results from the GET-LALA group.

Outcome of adult acute lymphoblastic leukemia (ALL) with central nervous system (CNS) involvement is not clearly defined. We studied 104 patients presenting with CNS involvement at diagnosis among 1493 patients (7%) included into the LALA trials, and 109 patients presenting CNS disease at the time of first relapse among the 709 relapsing patients (15%). Eighty-seven patients (84%) with CNS leukemia at diagnosis achieved complete remission (CR). Fifty-three patients underwent stem cell transplantation (SCT): 25 allogeneic SCT, 28 autologous SCT, while 34 continued with chemotherapy alone. Seven-year overall survival (OS) and disease-free survival (DFS) were 34% and 35%, respectively. There were no significant differences in terms of CR, OS and DFS among patients with CNS involvement at diagnosis and those without CNS disease. There were also no differences among the two groups regarding T lineage ALL, B lineage ALL, and among those who underwent SCT. After a first relapse, 38 patients with CNS recurrence (35%) achieved a second CR. The median OS was 6.3 months. Outcome was similar to that of relapsing patients without CNS disease. CNS leukemia in adult ALL is uncommon at diagnosis as well as at the time of first relapse. With intensification therapy, patients with CNS leukemia at diagnosis have a similar outcome than those who did not present with CNS involvement. CNS leukemia at first relapse remains of similar poor prognosis than all other adult ALL in first relapse.