Analysis of chemotherapy-induced neutropenia and optimal timing for prophylactic use of G-CSF in B-cell non-Hodgkin lymphoma patients treated with R-CHOP.

BACKGROUND: Febrile neutropenia (FN) is one of the serious complications of chemotherapy. However, the hematological nadir after chemotherapy and the timing of prophylaxis for FN remain unclear, especially for outpatients.
METHODS: We prospectively analyzed laboratory data from outpatients treated with a single chemotherapy regimen, rituximab (R)-CHOP, on three consultation days (days 8, 10, and 15) after chemotherapy to identify any factors that might predict the onset of the hematological nadir and the optimal timing of G-CSF prophylaxis.
RESULTS: A total of 100 courses of chemotherapy (total 33 patients) were analyzed. Onset of the hematological nadir was not predictable in any of the patients who had a white blood cell count (WBC) of >5,500 × 10(6)/L and/or monocyte count of >80 × 10(6)/L on day 8, and thus there was little opportunity for G-CSF prophylaxis in each treatment course. Among patients who had a WBC count of 1,500-5,500 × 10(6)/L on day 8, the monocyte count on day 8 was significantly associated with the hematological nadir. Patients who had a monocyte count of <5 × 10(6)/L on day 8, were identified as a high-risk group for neutropenia for whom G-CSF administration during the current treatment course should be considered.
CONCLUSION: Our results indicate that, in outpatients receiving R-CHOP chemotherapy, the monocyte count on day 8 is a useful marker of the hematological nadir, allowing an opportunity for G-CSF prophylaxis.