title: Prognosis and outcome of relapsed acute lymphoblastic leukemia: a Hong Kong Pediatric Hematology and Oncology Study Group report.
abstract: BACKGROUND
  In 2000, the Hong Kong Pediatric Hematology Oncology Study Group started a new relapsed acute lymphoblastic leukemia (ALL) treatment protocol based on modified ALL-REZ BFM 96 protocol aiming at improving the treatment outcome in Chinese children.
  
  
  METHODS
  All patients in Hong Kong with first relapse of childhood ALL were included. Patients were stratified into four risk groups (S1, S2, S3, and S4) and the treatment consisted of intensive chemotherapy followed by allogeneic hematopoietic stem cell transplantation, if indicated.
  
  
  RESULTS
  Fifty-six patients were recruited and median age at diagnosis of ALL was 4.6 (range, 0.3-17) years. The median time from initial diagnosis to relapse was 2.5 (range, 0.3-9.1) years and follow-up time was 2.7 (range, 0-9.9) years. Forty-nine patients (87.5%) achieved second complete remission (CR2). CR2 rates for S1, S2, S3, and S4 groups were 100%, 93%, 90%, and 67%, respectively. Five-year overall survival (OS) was 50.5 ± 6.9% and event-free survival (EFS) was 41.5 ± 7.1%. There was no significant difference in survival among S1, S2, and S3 groups but S4 patients performed significantly worse with 5-year OS and EFS of 8% and 0%, respectively.
  
  
  CONCLUSIONS
  Children with relapsed ALL of S1-S3 risk groups could be successfully treated with intensified treatment protocol. The S4 high risk group needs more innovative approach to improve treatment outcome.
authors.affiliation: Department of Paediatrics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Alex Wing Kwan
authors.initials: AW
authors.lastname: Leung
authors.forename: Lee
authors.initials: L
authors.lastname: Vincent
authors.forename: Alan Kwok Shing
authors.initials: AK
authors.lastname: Chiang
authors.forename: Anselm Chi Wai
authors.initials: AC
authors.lastname: Lee
authors.forename: Frankie Wai Tsoi
authors.initials: FW
authors.lastname: Cheng
authors.forename: Daniel Ka Leung
authors.initials: DK
authors.lastname: Cheuk
authors.forename: Chung Wing
authors.initials: CW
authors.lastname: Luk
authors.forename: Siu Cheung
authors.initials: SC
authors.lastname: Ling
authors.forename: Chi Kong
authors.initials: CK
authors.lastname: Li
mesh_terms: D000293:Adolescent; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003131:Combined Modality Therapy; D018572:Disease-Free Survival; D005260:Female; D018380:Hematopoietic Stem Cell Transplantation; D006723:Hong Kong; D006801:Humans; D007223:Infant; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy* / Q000401:mortality / Q000628:therapy; D011379:Prognosis; D012008:Recurrence; D012074:Remission Induction; D012307:Risk Factors; D016896:Treatment Outcome