Improved outcome of acute lymphoblastic leukaemia treated by delayed intensification in Hong Kong children: HKALL97 study

Hong Kong Med J. 2006 Feb;12(1):33-9.


Objective: To study the outcome of children with acute lymphoblastic leukaemia who were treated using a protocol including one or two delayed intensifications.

Design: Prospective single-arm multicentre study.

Setting: Five designated children cancer units of the Hospital Authority of Hong Kong.

Patients: Children aged between 1 and 17.9 years with newly diagnosed acute lymphoblastic leukaemia seen from November 1997 to December 2002.

Intervention: Chemotherapy was modified from a German Berlin-Frankfurt-Muenster 95 (BFM95) protocol that included a delayed intensification similar to the induction phase repeated 5 months after diagnosis. High-risk patients were given double delayed intensification.

Main outcome measures: Overall survival and event-free survival of the whole group and the three risk groups (standard-, intermediate-, and high-risk groups), and comparison with historical controls.

Results: A total of 171 patients were recruited with a median age at diagnosis of 5.57 years (range, 1.15-17.85 years). The induction remission rate was 95.3% and non-leukaemia mortality during remission was 2.3%. At 4 years, the relapse rate of this (HKALL97) study was significantly lower than that of the HKALL93 study (15.7 vs 37.3%; P<0.001). The 4-year overall survival of HKALL97 and HKALL93 studies were 86.5% and 81.8%, respectively (P=0.51). The 4-year event-free survival for HKALL97 and HKALL93 studies were 79% and 65%, respectively (P=0.007). Nonetheless the difference of event-free survival was most remarkable in the intermediate-risk group: 75.6% and 53.1% for HKALL97 and HKALL93 studies, respectively (P=0.06).

Conclusion: A more intensive delayed consolidation phase improved the outcome for children with acute lymphoblastic leukaemia by reducing relapses at 4 years. The early treatment complications were manageable and non-leukaemia mortality during remission remained low.

Publication types

  • Clinical Trial
  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use*
  • Child
  • Child, Preschool
  • Disease-Free Survival
  • Female
  • Hong Kong / epidemiology
  • Humans
  • Infant
  • Male
  • Neoplasm Recurrence, Local / epidemiology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / drug therapy*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / mortality*
  • Prospective Studies
  • Remission Induction
  • Risk Assessment
  • Survival Rate