Improved outcome of acute lymphoblastic leukaemia treated by delayed intensification in Hong Kong children: HKALL 97 study

摘要

Objective. To study the outcome of children with acute lymphoblastic leukae-mia who were treated using a protocol including one or two delayedintensifications.Design. Prospective single-arm multicentre study.Setting. Five designated children cancer units of the Hospital Authority of HongKong.Patients. Children aged between 1 and 17.9 years with newly diagnosed acutelymphoblastic 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 tothe induction phase repeated 5 months after diagnosis. High-risk patients weregiven double delayed intensification.Main outcome measures. Overall survival and event-free survival of the wholegroup 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 of5.57 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 relapserate of this (HKALL97) study was significantly lower than that of the HKALL93study (15.7 vs 37.3%; P<0.001). The 4-year overall survival of HKALL97 andHKALL93 studies were 86.5% and 81.8%, respectively (P=0.51). The 4-yearevent-free survival for HKALL 97 and HKALL93 studies were 79% and 65%,respectively (P=0.007). Nonetheless the difference of event-free survival wasmost remarkable in the intermediate-risk group: 75.6% and 53.1% for HKALL97and HKALL93 studies, respectively (P=0.06).Conclusion. A more intensive delayed consolidation phase improved the out-come for children with acute lymphoblastic leukaemia by reducing relapses at 4years. The early treatment complications were manageable and non-leukaemiamortality during remission remained low