The EORTC Children's Leukemia Group: Preclinical and clinical research and resulting achievements

The EORTC Children's Leukemia Group (CLG) is a spin-off from the EORTC Hemopathies Working Party (adults and children). After a decade of collaboration in the adult-pediatric group it became clear that there was not only a large difference in cure rates between children and adults, but many chemotherapeutic-toxic borders were substantially different. During the following decade the CLG was not only a witness of a very exciting battle against childhood leukemia, but it also contributed substantially to better cure rates for these diseases.The main activity of the CLG was concentrated on the field of acute lymphoblastic leukemia (ALL). Fine tuning of treatment elements using the BFM design as a backbone has been done very successfully over the past decades. The CLG has many achievements, and the major ones include: the 58831 trial showing the superfluity of the prophylactic Central Nervous System (CNS) radiotherapy in ALL patients when a adequate systemic and CNS directed chemotherapy is ascertained. The 58881 trial demonstrated that the assessment of minimal residual disease (MRD) at completion of induction in ALL is a key step in the process to categorizing and allocating patients into different risk groups, and that MRD is a powerful and independent prognostic factor. This same 58881 trial showed the clear difference in efficacy of different asparaginases resulting in an optimization of the use these drugs and a revival of interest for the asparaginases in the treatment of ALL.In the near future the CLG will focus mainly on translational research projects and innovative biologically targeted treatment approaches, on collaborations with other children's leukemia groups in intergroup studies, and on the evaluation of the long-term outcome of childhood cancer survivors.