Splenic irradiation in myelofibrosis with myeloid metaplasia: a review

Morbidity from myeloid metaplasia and myelofibrosis arises from progressive anemia and abdominal discomfort related to massive splenomegaly, which may be associated with hypercatabolic symptoms. To date, no therapy, other than allogeneic bone marrow transplantation, has been shown to cure or to prolong the survival of these patients. Thus, current management strategies are palliative and include red cell transfusional support and androgen therapy for anemia; chemotherapeutic agents for control of thrombocytosis, leukocytosis, and hypermetabolic symptoms; and splenectomy or splenic irradiation for symptomatic splenomegaly. The major indication for splenic irradiation is left upper quadrant discomfort related to massive splenomegaly, usually in patients for whom splenectomy is contraindicated or has been declined. In most patients, it provides relief from abdominal pain and a moderate reduction in splenic size. Although responses are transient, some patients may experience prolonged relief. Splenic irradiation can result in prolonged myelosuppression in certain patients. This calls for cautious dosing, because individual sensitivity is variable and cannot be predicted. The use of splenic irradiation does not preclude subsequent splenectomy; however, the increased risk of postoperative hemorrhage should discourage consideration of splenic irradiation as an alternative or a temporizing measure before splenectomy when indicated.