Eligibility for allogeneic transplantation in very high risk childhood acute lymphoblastic leukemia: the impact of the waiting time

1 Clinica Pediatrica, Università degli Studi di Milano Bicocca, Monza, Italy; 2 Dipartimento di Medicina Clinica e Prevenzione, Università degli Studi di Milano Bicocca, Monza, Italy; 3 Department of Pediatrics, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany; 4 Stammzelltransplantations-Einheit, St. Anna Kinderspital, Wien, Austria; 5 Klinik für Kinderheilkunde III, Klinikum der J.W. Goethe Universität, Frankfurt, Germany; 6 Department of Pediatric Hematology/Oncology, University Hospital Motol, Prague, Czech Republic; 7 Department of Pediatric Hematology/Oncology, Hospital de Pediatría Prof. Dr. Juan P. Garrahan, Buenos Aires, Argentina; 8 Department of Pediatric Clinic at the Semmelweis Medical University, Budapest, Hungary and 9 Department of Pediatric Hematology/Oncology, Istituto G. Gaslini, Genova, Italy Correspondence: Adriana Balduzzi, MD, Clinica Pediatrica Università degli Studi di Milano Bicocca, Ospedale San Gerardo, via Pergolesi 33, 20052 Monza, Milan, Italy. E-mail: adriana.balduzzi{at}pediatriamonza.it ABSTRACT The advantage of allogeneic transplant from compatible related donors versus chemotherapy in children with very-high-risk acute lymphoblastic leukemia in first complete remission was previously demonstrated in an international prospective trial. This study quantified the impact of time elapsed in first remission in the same cohort. Of 357 pediatric patients with very-high-risk acute lymphoblastic leukemia, 259 received chemotherapy, 55 transplantation from compatible related and 43 from unrelated donors. The 5-year disease-free survival was 44.2% overall and 42.5% for chemotherapy only patients. The chemotherapy conditional 5-year disease-free survival increased to 44.4%, 47.6%, 51.7%, and 60.4% in patients who maintained their first remission for at least 3, 6, 9, and 12 months respectively. The overall outcome was superior to that obtained with chemotherapy-only at any time-point. The relative advantage of transplant from compatible related donors in very-high-risk childhood acute lymphoblastic leukemia was consistent for any time elapsed in first remission. Key words: acute lymphoblastic leukemia, childhood, very high risk, waiting time to transplant, allogeneic transplantation.