Palliative irradiation of the spleen

We analyzed the efficacy of splenic irradiation in a population of patients with hematologic diseases. The records of the Radiation Oncology Division, Naval Medical Center San Diego were retrospectively reviewed for all patients treated with splenic irradiation (SI) between January 1, 1990 and March 1, 2001. The charts of 17 patients were identified: 5 patients had chronic myelogenous leukemia, 4 had chronic lymphocytic leukemia, 4 had idiopathic myelofibrosis, 2 had polycythemia vera, and I patient each had idiopathic thrombocytopenic purpura and acute myelogenous leukemia. Patient ages ranged from 37 to 88 years. Sixteen of 17 suffered from symptomatic splenomegaly. Twenty-six courses of splenic irradiation were delivered to these 17 patients. Treatment courses generally consisted of two fractions of 50 cGy in the first week, two fractions of 75 cGy the second week, and two fractions of 100 cGy the third week. Blood counts were checked prior to each treatment. Seven of the 17 patients died I month or less after SI due to the terminal nature of their disease. Twenty-two of 25 treatment courses for splenomegaly resulted in decreased pain and symptoms. Five patients required two treatment courses for splenomegaly, and one patient required five treatment courses. Three of four patients treated for thrombocytopenia demonstrated improvement, but only one was evaluable for more than 2 weeks due to disease-related mortality. Three of five patients treated for leukocytosis had significant improvement. In general, patients suffered few significant complications from this palliative intervention. Splenic irradiation can effectively palliate symptomatic splenomegaly in patients for whom splenectomy is not an option. Retreatment is possible. Splenic irradiation is less effective in the treatment of thrombocytopenia or leukocytosis.