Improved cure rate in children with B-cell acute lymphoblastic leukaemia (B-ALL) February 1996, 35 patients with B-cell acute lymphoblastic leukaemia (B-ALL) 13 of whom had CNS disease and 28 patients with stage IV B-cell non-Hodgkin's lymphoma (B-NHL) 22 of whom had CNS involvement were treated with a short, intensive multiagent chemotherapy regimen (UKCCSG 9003 protocol) based on the French LMB 86 regimen. Fifty-five were boys. The age range was 11 months to 16.5 years (median 8.4 years). Chemotherapy included cyclophosphamide, vincristine, daunorubicin, high-dose methotrexate (COPADM) and etoposide/high-dose cytarabine (CYVE) with frequent intrathecal (i.t.) triple therapy (methotrexate, cytarabine and hydrocortisone). Cranial irradiation (24 Gy in 15 fractions) was recommended in patients with overt CNS disease. One patient with WiskottAldrich syndrome was withdrawn after entry and has been excluded from the analysis. Ten patients (16%) have relapsed (CNS, four; BM, two; combined CNS and BM, three; and jaw, one) 4-11 months after diagnosis and two patients never achieved complete remission (CR). All have died. In seven of the patients who relapsed, treatment had been modified or delayed because of poor clinical condition. Seven patients (11 %) died of toxicity 11 days to 4 months after diagnosis. The cause of death was sepsis (n = 5) or sepsis with renal failure (n = 2). With a median follow-up of 3.1 years from diagnosis (range 9 months to 6.3 years), 43 patients (69%) survive in CR. This study confirms the effectiveness of this regimen with regard to the relapse rate (16%), although the rate of toxic death is of concern.Keywords: high risk; paediatric cancer; B-cell acute lymphoblastic leukaemia; B-cell non-Hodgkin's lymphomaThe treatment of B-NHL in children is one of the success stories in paediatric oncology. The cure rate has increased from less than 20% before 1980 (Al-Attar et al, 1979) to over 70% in the 1980s and 1990s (Philip et al, 1982;Al-Attar et al, 1986;Patte et al, 1990). Recent studies have concentrated on improving outcome in the remaining poor-risk subgroups (Hann et al, 1988;Patte et al, 1991;Cairo et al, 1996), reducing early deaths by aggressive treatment of early renal and infectious complications (Lynch et al, 1977;Allegretta et al, 1985) and avoiding debulking surgery (Frappaz et al, 1988;Al-Attar et al, 1989).In 1986, the French paediatric oncology group (SFOP) introduced a regimen for poor-risk patients with increased intensity of early intrathecal (i.t.) therapy and the use of high-dose cytarabine (LMB 86). Before this, results in patients with CNS disease were disappointing, despite the use of craniospinal irradiation with chemotherapy regimen, which was very effective in less advanced disease (Philip et al, 1982;Chilcote et al, 1991). The subsequent results with LMB 86 were dramatic, with a survival rate over 70% (Rubie et al, 1988). Relapse of the underlying disease remains a major cause of treatment failure. The use of high-dose cytarabine and etoposide (CYVE) may he...