Properly managed, the myeloproliferative disorders are generally compatible with prolonged survival. Challenges to the hematologist include knowing when and how best to intervene to prevent and manage complications. The cytoreductive agent of choice for these disorders is currently hydroxyurea, emerging from randomized trials beginning with those of the Polycythemia Vera Study Group.
To examine the roles and shortcomings of interventions (including hydroxyurea, antiplatelet agents, anagrelide, interferon, thalidomide, alkylating agents, cell cytopheresis, erythropoietins, splenectomy, bone marrow transplantation, and imatinib) for myeloproliferative disorders.
This report uses actual case histories to illustrate the roles and shortcomings of these interventions.
Beyond phlebotomy for polycythemia vera, patients with polycythemia vera and essential thrombocythemia can be stratified by their risk for thrombosis, which guides the institution of cytoreductive therapies. High-risk patients generally benefit from cytoreductive therapy, and hydroxyurea has emerged as the agent of choice, because alkylating agents (and P32) have high leukemogenic potentials. Anagrelide and interferon are second-line agents. The addition of low-dose aspirin is beneficial for most, helping to prevent arterial thrombotic complications. Therapy in any of these disorders should be tailored to the unique characteristics of the individual patient. With myelofibrosis, therapeutic options run the gamut from observation, erythropoietic stimulators, cytotoxic agents, splenectomy, and bone marrow transplantation. Thalidomide and imatinib have shown some utility. Future challenges are the refinement of individualized treatment strategies and the development of targeted therapies based on rapidly expanding understanding of the molecular perturbations in these disorders.