Management of adult acute lymphocytic leukemia: present issues and key challenges

Abstract

Purpose: To discuss the controversies in current adult acute lymphocytic leukemia (ALL) management in relation to its different phases of therapy.

Design: A review of treatments in adult ALL from the English literature.

Results: Features signaling high risk for systemic relapse (older age, high WBC count at diagnosis, non-T-cell immunophenotype, Philadelphia chromosome (Ph)-positive karyotype, and longer time to achieve remission) are found in 60% to 70% of patients with adult ALL. These patients have a potential cure rate of 20% to 25%, compared with 60% to 70% for low-risk patients. Induction regimens with vincristine, anthracyclines, and corticosteroids appear to be optimal. Intensification-consolidation therapy increased cure rates modestly in adult ALL; higher-dose schedules of mercaptopurine (6-MP), methotrexate, and asparaginase may be beneficial. Maintenance therapy with 6-MP and methotrexate is suggested based on the worse outcome of patients in whom such maintenance was omitted. Allogeneic bone marrow transplantation (BMT) is indicated for patients in first remission with high-risk for relapse; autologous BMT for patients in first remission remains investigational. Patients with mature B-cell ALL require short-term, dose-intensive therapy that alternates hyperfractionated doses of cyclophosphamide with high-dose cytarabine (ara-C) and methotrexate. Patients with T-cell ALL may benefit from ara-C/cyclophosphamide combinations during maintenance therapy. CNS prophylaxis with intrathecal chemotherapy should be administered in patients at risk for CNS relapse.

Conclusion: Potential strategies to improve the prognosis of high-risk patients with ALL include increasing the dose-intensity of remission induction and consolidation-intensification therapies with growth factor support; discovering and using new anti-ALL drugs; improving autologous BMT results; translating biologic studies of leukemia cell characteristics, karyotype-related molecular aberrations, abnormal oncogenic expression, and minimal residual disease into clinically relevant therapies; and using investigational treatment strategies in high-risk patients.