Hematopoietic stem cell transplantation for myelofibrosis.

Myelofibrosis with myeloid metaplasia (MMM) is a clonal disorder resulting from the proliferation of aberrant hematopoietic progenitors. Hence MMM is curable if the abnormal clone can be eradicated and replaced by normal cells from healthy donors. Myeloablative allogeneic transplantation results in high rates of durable engraftment and cure in approximately 50% of patients. Treatment-related mortality rather than disease recurrence accounts for the majority of treatment failures. Higher rates of treatment failure are associated with more advanced disease and age. More recently, nonmyeloablative (reduced-intensity) conditioning regimens have been shown to induce encouraging rates of engraftment and prolonged survival. When recommending transplantation for a particular patient, the prospect of cure should be weighed against the considerable risks of the procedure. Transplantation is typically recommended for patients under the age of 50 years with intermediate- and high-risk features, or for patients aged 50 to 60 years with an anticipated survival of less than 5 years. Finally, autologous transplantation has also been evaluated as a potential treatment approach. This procedure is unlikely to be curative, but might have a palliative role.