GRANULOCYTE-COLONY-STIMULATING FACTOR TREATMENT OF LEUKOPENIA DURING FRACTIONATED RADIOTHERAPY

11 patients suffering from an isolated leucopenia during fractionated radiotherapy were treated with granulocyte colony stimulating factor. (G-CSF). 4 of the patients received radiotherapy alone, and 7 patients received concomitant chemotherapy. G-CSF treatment was initiated at t he occurrence of leucopenia and maintained for the duration of radioth erapy. The applied daily dose was 5 mu g/kg subcutaneously. 10 of the 11 treated patients reacted with an increased leucocyte count, from an average of 1342 leucocytes per mu l(+/- 502/mu l) to 24 568 leucocyte s per mu l(+/- 950/mu l). Neutrophil counts increased on average from 64.9%(+/- 13.9%) to 91.1%(+/- 2.3%) (n = 7). In 1 patient thrombocytop enia occurred during the continued radiotherapy. 1 other patient react ed with an unexplained fall of leucocytes after two doses of G-CSF and one fraction of mediastinal irradiation. Side-effects observed during G-CSF treatment consisted oi. mild bone pain (1/11) and transient inc reases of serum alkaline phosphatase levels (4/11). Our observations i ndicate that G-CSF treatment is well tolerated during continuous fract ionated radiotherapy. Therefore, we conclude that G-CSF can be used cl inically to alleviate neutropenia caused by radiotherapy or by combine d radio-chemotherapy.