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RELAPSED LYMPHOBLASTIC LEUKAEMIA IN CHILDREN: A CONTINUING CHALLENGE

The treatment of childhood lymphoblastic leukaemia has been one of the success stories of haematology, but despite this triumph 25–30% of children still relapse. Relapsed lymphoblastic leukaemia (R-ALL) is thus as common as most paediatric solid tumours, and more common than acute myeloid leukaemia in childhood. The treatment of R-ALL is usually unsuccessful, causes heartache and stress for both families and staff, and consumes large amounts of time and resources. There have been few randomized therapeutic trials to inform the choice of treatment and intense medical and lay interest in high-dose therapy and all variants of stem cell rescue. The increased availability of bone marrow or stem cells donors raises the vision that, in theory, BMT could be available to all children with R-ALL at least in societies whose resources permit this option. Yet high-dose therapy carries at least a 10–20% risk of immediate death and a much greater risk of delayed complications such as growth failure, infertility, organ damage and neuropsychological impairment, and is itself associated with a high relapse rate. This article will attempt to review the therapeutic options for the child with R-ALL, to make recommendations based on the limited evidence available about choice of treatment, and to suggest priority areas for research. It must, however, be recognized that this whole topic is clouded by a lack of randomized trials, difficulties over selection bias, and publications involving small numbers of patients.