Timing of G-CSF Administration Based on the Circadian Rhythm in Patients With Ovarian Cancer

The aim of this study was to determine the relationship between the timing of granulocyte colony-stimulating factor (G-CSF) administration and its efficacy in patients with chemotherapy-induced granulocytopenia. Twenty patients in whom chemotherapy-induced leukopenia developed after the first course were enrolled in this prospective study. Subjects were randomly divided in two groups according to G-CSF injection time as follows: at 7:00 am and 7:00 pm. Before the G-CSF injection, the plasma G-CSF level for all patients was significantly lower at 7:00 am than that at 7:00 pm. After the injection, plasma G-CSF level did not differ between the two groups. The nadir of the leukocyte was 2,554 ± 379/mm3 (granulocyte 1,530 ± 689) for the group injected at 7:00 am, and 2,300 ± 426/mm3 (granulocyte 1,203 ± 848) for the group injected at 7:00 pm. The duration of leukocytes less than 2,000/mm3 and granulocytes less than 1,000/mm3 were 2.8 ± 1.8 days and 3.2 ± 1.8 days, respectively. Those differences were not significant. The present study showed the circadian rhythm of G-CSF levels in patients with ovarian cancer with chemotherapy-induced granulocytopenia, but there was no remarkable difference depending on administration time.