Central nervous system relapse in acute lymphoblastic leukemia: prognostic factors and the outcome

ABSTRACT

Despite the advances in treatment of acute lymphoblastic leukemia [ALL], CNS relapse remains an obstacle to successful treatment. This study was performed to determine the frequency of CNS relapse in ALL patients and to study risk factors and outcome after CNS relapse. A retrospective study done on 364 patients diagnosed as ALL in Central Teaching Hospital for Children-Baghdad for the period from 1[st] Jan 2000 to 31[st] Mar 2005. ALL patients whom diagnosed after 1[st] Jan 2004 received CTHC 2004 protocol .The following parameters were studied gender, age, hepatomegaly, splenomegaly, LAP, mediastinal mass, initial WBC count, platelets count, FAB morphology, initial CNS involvement and if the patient received radiotherapy. 35 patients were excluded from the study. Out of 329 eligible patients, 76 patients [23.1%] had CNS relapse [isolated or combined], with mean duration before CNS relapse 12.30 +/- 8.28 months and median of 11 months. The following factors were significantly associated with development of CNS relapse male gender, age <2 years, massive hepatomegaly, massive splenomegaly, lymphadenopathy, mediastinal mass, initial WBC count >/= 50000/mm, initial CNS involvement, and patients who did not receive prophylactic CNS radiation. The study shows that frequency of CNS relapse decreased significantly after addition of three intrathecal doses during induction]. Shorter duration between diagnosis of ALL and CNS relapse was associated with higher mortality. Frequency of CNS relapse and mortality rate still higher than globally-accepted figures. Intensification of systemic and CNS-directed therapy, significantly decreased these figures in our patients