Introduction: The first multi-centric protocol for childhood acute lymphoblastic leukaemia (ALL) treatment in Spain started in 1989 and was conducted by the Spanish Pediatric Hematology and Oncology Societies.
Materials and methods: A total of 673 patients were included in two consecutive trials, SHOP-89 (1989-1993) and SHOP- 94 (1994-1998). Approximately 67% of the children diagnosed with ALL in Spain during this period were enrolled in these trials. The 250 eligible patients enrolled in the SHOP- 89 study were stratified to either a standard or a high-risk group. Therapy schedule was based on the central nervous system (CNS) therapy designed by St Jude CRH and the Children's Cancer Group, and the post-induction intensification developed by the BFM group. In the SHOP-94 study, a further high-risk group was included in the stratification of the 423 enrolled patients. The therapeutic protocol was characterised by intensification of systemic chemotherapy and the administration of cranial radiotherapy only to patients at high risk of relapse or with CNS involvement at diagnosis.
Results: Event-free survival (EFS) increased from 0.57+/- 0.03 at 15 years in SHOP-89, to 0.68+/-0.03 at 11 years in SHOP-94 (p=0.01). Relapse rate decreased from SHOP-89 to SHOP-94: 0.38 vs. 0.25 (p=0.01). CNS relapse rate was 9.1% in SHOP-89 and 4.6% in SHOP-94 (p=0.001). EFS in patients with T-immunophenotype was 0.40+/-0.08 in SHOP-89 and 0.44+/-0.06 in SHOP-94 (p=ns).
Conclusions: Our therapeutic results evidence a significant improvement in EFS and systemic and CNS relapse rates among the two consecutive trials after modification of patient stratification and intensification of systemic chemotherapy.