Outcome of children with high-risk acute lymphoblastic leukemia (HR-ALL): Nordic results on an intensive regimen with restricted central nervous system irradiation

Background Improvement in outcome of childhood high‐risk (HR) ALL was sought with a very intensive Nordic protocol leaving most patients without CNS‐RT. Methods A total of 426 consecutive children entered the NOPHO‐92 HR‐ALL program. HR criteria included WBC ≥ 50 × 109/L, CNS or testicular involvement, T‐cell, lymphomatous features, t(9;22), t(4;11), or slow response. Of these, 152 children had very high risk (VHR) with special definitions. CNS consolidation was based on high‐dose MTX (8 g/m2) and ARA‐C (12 g/m2) alternating. VHR patients also received cranial RT. Results The 9‐year EFS was 61 ± 3%, OS 74 ± 2%, and EFS for T‐ALL 62 ± 4%. Cumulative incidence of isolated CNS relapse was 4.7 ± 1%, and CNS relapse in total 9.9 ± 2%. Poor prognostic factors were WBC ≥ 200 × 109/L and a very slow response. Conclusions HR‐ALL was successfully treated on the NOPHO‐92 regimen, with a relatively low CNS relapse rate for non‐irradiated children. WBC ≥ 200 × 109/L and very slow response emerged as strong poor prognostic factors. © 2003 Wiley‐Liss, Inc.