Blood Journal
Leading the way in experimental and clinical research in hematology

New prognostic scoring system for primary myelofibrosis based on a study of the International Working Group for Myelofibrosis Research and Treatment

  1. Francisco Cervantes1,
  2. Brigitte Dupriez2,
  3. Arturo Pereira1,
  4. Francesco Passamonti3,
  5. John T. Reilly4,
  6. Enrica Morra5,
  7. Alessandro M. Vannucchi6,
  8. Ruben A. Mesa7,
  9. Jean-Loup Demory2,
  10. Giovanni Barosi8,
  11. Elisa Rumi3, and
  12. Ayalew Tefferi7
  1. 1Hematology Department, Hospital Clínic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Spain;
  2. 2Centre Hospitalier, Lens and Lille, France;
  3. 3Hematology Division, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Policlinico S Matteo, University of Pavia, Pavia, Italy;
  4. 4Royal Hallamshire Hospital, Sheffield, United Kingdom;
  5. 5Universita Milano-Niguarda, Milan, Italy;
  6. 6University of Florence, Florence, Italy;
  7. 7Division of Hematology, Mayo Clinic College of Medicine, Rochester, MN; and
  8. 8Unit of Clinical Epidemiology, Center for the Study of Myelofibrosis, Fondazione IRCCS Policlinico S Matteo, Pavia, Italy


Therapeutic decision-making in primary myelofibrosis (PMF) is becoming more challenging because of the increasing use of allogeneic stem cell transplantation and new investigational drugs. To enhance this process by developing a highly discriminative prognostic system, 1054 patients consecutively diagnosed with PMF at 7 centers were studied. Overall median survival was 69 months (95% confidence interval [CI]: 61-76). Multivariate analysis of parameters obtained at disease diagnosis identified age greater than 65 years, presence of constitutional symptoms, hemoglobin level less than 10 g/dL, leukocyte count greater than 25 × 109/L, and circulating blast cells 1% or greater as predictors of shortened survival. Based on the presence of 0 (low risk), 1 (intermediate risk-1), 2 (intermediate risk-2) or greater than or equal to 3 (high risk) of these variables, 4 risk groups with no overlapping in their survival curves were delineated; respective median survivals were 135, 95, 48, and 27 months (P < .001). Compared with prior prognostic models, the new risk stratification system displayed higher predictive accuracy, replicability, and discriminating power. In 409 patients with assessable metaphases, cytogenetic abnormalities were associated with shorter survival, but their independent contribution to prognosis was restricted to patients in the intermediate-risk groups. JAK2V617F did not cluster with a specific risk group or affect survival.

  • Submitted July 23, 2008.
  • Accepted October 21, 2008.
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