Indications and role of allogeneic bone marrow transplantation in childhood very high risk acute lymphoblastic leukemia in first complete remission.

BACKGROUND AND OBJECTIVES

Acute lymphoblastic leukemia (ALL) accounts for approximately one third of all cancers in children and its outcome depends on risk factors at the time of diagnosis. While uniform chemotherapy adopted in multicenter studies provided a constant improvement in cure rates for standard risk patients, the results reached in very high risk patients have been disappointing. The objective of this review is to point out the role of allogenic bone marrow transplantation (alloBMT) in very high risk childhood ALL on the basis of results from the current clinical trials. EVIDENCE AND INFORMATION SOURCE: Data covered by Medline and produced by the authors involved in ongoing international studies cover a vast "scenario" of children with very high risk ALL who underwent allogeneic BMT.

STATE OF ART

The author outlines the crucial point of very high risk factors in childhood ALL in order to identify those children who are at risk of early relapse. The main reasons for pursuing alloBMT in this particular category of patients concern poor prognostic factors such as molecular biology markers, structural chromosomal abnormalities and biological factors (poor prednisone response) including resistance to initial induction chemotherapy. AlloBMT in childhood ALL in first complete remission seemed to lead to a promising disease-free survival in this patient population when compared with chemotherapy. The principal biases of the retrospective studies were the variable very high risk eligibility criteria, the different first-line therapies adopted before alloBMT and above all the waiting time to transplant which could have accounted for some advantage to alloBMT patients versus chemotherapy patients.

PERSPECTIVES

The author touches upon the preliminary results of an ongoing international prospective study as an example of reaching a consensus in the controversial treatment of childhood very high risk ALL. This attempt should provide more information regarding the role of alloBMT in this setting and should cover an area of particular interest.