Splenic radiation for corticosteroid-resistant immune thrombocytopenia

Objective: To determine the role of splenic radiation as a treatment for immune thrombocytopenia. Design: Retrospective analysis of an open, nonrandomized investigation. Setting: A regional cancer center, referred care, and primary care settings. Patients: Eleven older patients with idiopathic thrombocytopenic purpura (ITP) and 8 patients with secondary immune thrombocytopenia refractory to corticosteroid treatment for whom surgery would have posed a high risk. Intervention: A short course (1 to 6 weeks) of radiation therapy to the spleen (total dose, 75 to 1370 cGy) with or without concurrent and postradiation corticosteroid administration. Measurements: Efficacy was assessed by measuring any increase in the platelet count and by monitoring the duration of response and side effects. Results: Of 11 patients with ITP, 8 patients responded. Three patients had a sustained (> 52 weeks) increase in the platelet count to safe levels after therapy was discontinued. An additional patient had a sustained response but required intermittent, low-dose corticosteroids. Four other patients had increases in their platelet counts that lasted from 8 to 25 weeks. Two of the eight patients without ITP had a positive response, whereas four did not respond, and two were not evaluable. Patients had no adverse reactions to the radiation treatment. Conclusion: Splenic radiation can be a safe and effective method to raise the platelet count in older patients with ITP that is refractory to corticosteroids and in whom the risks associated with splenectomy are high.