title: Therapy-related acute lymphoblastic leukemia is more frequent than previously recognized and has a poor prognosis.
abstract: BACKGROUND
  Acute lymphoblastic leukemia (ALL) occurring in patients with a history of prior chemotherapy/radiotherapy exposure has been previously reported to be rare, accounting for <2.5% of ALL cases.
  
  
  METHODS
  All cases of adult ALL with a history of prior cytotoxic or radiation therapy at a leukemia referral center over a 13-year period were analyzed.
  
  
  RESULTS
  Twenty-three cases, representing 6.9% of all ALL cases, were identified. Of these, 17 (74%) had at least 1 high-risk feature; 8 (35%) had MLL rearrangements, and 4 were BCR-ABL(+) . MLL rearrangements were correlated with CD15 expression and absence of CD10, and also tended to have a shorter mean latency period and more prior topoisomerase II exposure. Twenty-one patients received induction therapy, and 18 (86%) achieved a complete response, 17 with 1 induction. Six patients have relapsed and died, and 4 others died of other complications, 2 of these postallogeneic stem cell transplantation. Median disease-free survival (DFS) and overall survival (OS) were 27 and 13.6 months, respectively, and 3-year DFS and OS were 37.1% and 37.6%, respectively.
  
  
  CONCLUSIONS
  The frequency of therapy-related ALL is higher than previously reported and has a poor prognosis, probably related to the high frequency of adverse risk features.
authors.affiliation: Department of Medical Oncology and Hematology, Princess Margaret Hospital, Toronto, Ontario, Canada.
authors.forename: Amal
authors.initials: A
authors.lastname: Abdulwahab
authors.forename: Jenna
authors.initials: J
authors.lastname: Sykes
authors.forename: Suzanne
authors.initials: S
authors.lastname: Kamel-Reid
authors.forename: Hong
authors.initials: H
authors.lastname: Chang
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Brandwein
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects*; D018572:Disease-Free Survival; D005260:Female; D011495:Histone-Lysine N-Methyltransferase; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D051788:Myeloid-Lymphoid Leukemia Protein / Q000235:genetics; D009381:Neoplasms, Radiation-Induced / Q000401:mortality*; D016609:Neoplasms, Second Primary / Q000209:etiology* / Q000401:mortality / Q000628:therapy; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics / Q000401:mortality / Q000628:therapy; D011379:Prognosis; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; C497422:KMT2A protein, human; D051788:Myeloid-Lymphoid Leukemia Protein; D011495:Histone-Lysine N-Methyltransferase