Treatment approaches in myelofibrosis with myeloid metaplasia: The old and the new

Myelofibrosis with myeloid metaplasia (MMM) is currently classified as a chronic myeloproliferative disorder (CMPD) and is characterized by prominent bone marrow stromal reaction including collagen fibrosis, osteosclerosis, and angiogenesis. Among the CMPD, MMM carries the worst prognosis with an overall median survival of 5 years; the clinical course is marred by profound constitutional symptoms, progressive anemia, and symptomatic splenomegaly. Causes of death include leukemic transformation, which occurs in approximately 10% of patients in the first decade of the disease. At present, allogeneic hematopoietic stem cell transplantation (HSCT) is the only treatment modality that has the potential to either cure the disease or prolong survival. Both drug therapy and autologous HSCT are currently palliative. Conventional treatment agents in MMM include androgen preparations, corticosteroids, erythropoietin (EPO), and hydroxyurea. In addition, both splenectomy and radiation therapy have defined therapeutic roles. Thalidomide is the most effective investigational agent at the present time. Optimal therapy for an individual patient requires a sound understanding of disease risk factors, as well as a full appreciation of the risk to benefit ratio for a specific treatment modality.