Acute lymphoblastic leukemia in adults: recent progress, future directions

The data reviewed indicate substantial recent progress in the treatment of ALL in adults. Most patients, greater than 70% to 80%, will achieve a remission following induction chemotherapy with vincristine, prednisone, and an anthracycline. Additional drugs do not convincingly increase the remission rate; their effect on remission duration is unknown. Although continuation therapy has not been critically evaluated in randomized trials, the longest remissions have been reported in individuals receiving consolidation/intensification, particularly in the immediate postremission period. Presently, a disease-free survival is 35% to 45% at greater than 5 years when this type of consolidation/intensification therapy is used. The precise value of conventional maintenance chemotherapy in adult ALL is unknown. CNS prophylaxis is necessary; the standard of treatment remains cranial radiation and intrathecal methotrexate. Alternative approaches are currently being studied such as systemic treatment with high doses of methotrexate or cytarabine. Recently, prognostic factors have been better defined. In recent studies with intensive treatment, time to response, age, WBC, immunologic subtype and cytogenetic data can be used to divide patients into a low-risk group with a projected disease-free survival of 60% or more and a high-risk group with a disease-free survival of 20% to 25%. The definition of risk groups in adult ALL may be useful in determining future further optimal therapeutic approaches.