Comparison of two strategies for the treatment of radiogenic leukopenia using granulocyte colony stimulating factor.

Abstract

Radiation-induced leukopenia can cause a delay or discontinuation of radiotherapy. This complication can be overcome with the use of granulocyte colony-stimulating factor (G-CSF). However, an uncertainty exists regarding the mode of application of G-CSF in patients treated with radiotherapy. For this reason, the efficacy of two strategies for the administration of G-CSF in irradiated patients was compared in a prospective randomized clinical study. Forty-one patients who developed leukopenia (< 2.5 x 10(9) per liter) while undergoing radiotherapy were treated with G-CSF at a daily dose of 5 microg/kg. The first group received single injections of G-CSF as required (n = 21). The second group received G-CSF on at least 3 consecutive days (n = 20). An analysis was made of the changes in leukocyte counts, the number of days on which radiotherapy had to be interrupted, and the side effects of growth-factor treatment. An increase in leukocyte values in the peripheral blood was observed in all patients treated with G-CSF. In the group which received G-CSF when required, two injections (range: 1-8) were administered in most cases. In the second group, most of the patients received three injections (range: 3-9). The average duration of therapy interruptions due to leukopenia was 4.8 days (0-28) in the first therapy arm and 2.5 (0-20) in the second arm. The variance in the duration of therapy interruptions between the two groups was not significant (p = 0.2). Radiotherapy had to be terminated in two patients due to thrombocytopenia but the application of G-CSF did not seem to be a reason of decreasing platelet counts. Our results reveal that G-CSF is safe and effective in the treatment of radiation-induced leukopenia regardless of the mode of application. Because the calculated difference related to radiation treatment interruptions has no clinical relevance, both approaches examined in our study appear reasonable.