title: Second malignancies in hydroxyurea and interferon-treated Philadelphia-negative myeloproliferative neoplasms.
abstract: OBJECTIVE
  In an era of controversy in regard to 'hydroxyurea-leukaemogenicity' and when interferon-alfa2 (IFN) is being revived in the treatment of Philadelphia-negative myeloproliferative neoplasms (MPNs), we aim in this single-centre observational study to describe the frequencies of second malignancies in a cohort of MPN patients treated with hydroxyurea (HU) or IFN monotherapy or the combination of these agents.
  
  
  METHODS
  Records of a MPN cohort of 196 patients were reviewed, and a retrospective analysis was performed on 90 patients treated with HU, 38 patients treated with IFN and 68 patients treated with both IFN and HU. Logistic regression was used to compare frequencies in second malignancies.
  
  
  RESULTS
  Patients treated with HU had a significantly higher risk of developing all second malignancies compared with patients treated with IFN [HU vs. IFN: OR of 4.01 (95%CI: 1.12-14.27, P-value: 0.023) and HU-IFN vs. IFN: OR 5.58 (95%CI: 1.55-20.15, P-value: 0.004)].
  
  
  CONCLUSIONS
  We have found an increased risk of second malignancies in MPN patients treated with HU compared with patients treated with IFN.
authors.affiliation: Department of Haematology, Copenhagen University Hospital Roskilde, Copenhagen, Denmark.
authors.forename: Iben Onsberg
authors.initials: IO
authors.lastname: Hansen
authors.affiliation: Department of Haematology, Copenhagen University Hospital Roskilde, Copenhagen, Denmark.|Institute for Inflammation Research, Center for Rheumatology and Spine Diseases, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Anders Lindholm
authors.initials: AL
authors.lastname: Sørensen
authors.affiliation: Department of Haematology, Copenhagen University Hospital Roskilde, Copenhagen, Denmark.
authors.forename: Hans Carl
authors.initials: HC
authors.lastname: Hasselbalch
mesh_terms: D000328:Adult; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D006801:Humans; D006918:Hydroxyurea / Q000627:therapeutic use*; D016898:Interferon-alpha / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D016609:Neoplasms, Second Primary / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D016017:Odds Ratio; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D016898:Interferon-alpha; D006918:Hydroxyurea
keywords: essential thrombocythemia; myeloproliferative neoplasms; polycythemia vera