Aims: To review evidence behind therapeutic use of granulocyte colony stimulating factor (GCSF) and investigate if real-world data on dose timing and neutrophil recovery is representative of simulation studies that report a potential for detrimental outcomes.
Methods: A retrospective medical records review in adult cancer patients undergoing parenteral chemotherapy, dosed within the 30 days preceding admission for chemotherapy induced febrile neutropenia (CIFN) was done. Only medical oncology diagnoses treated with a 21-day chemotherapy protocol were included. Fever was defined as ≥38.0°C and neutropenia as <1.0x109/L. Data was analysed using descriptive and regression analyses. The research questions were, i) Does the timing of therapeutic GCSF impact neutrophil recovery? ii) Is the proposed relationship between monocyte and neutrophil count demonstrable in real-world practice? iii) Do the factors in questions (i) and (ii) have an impact on length of stay?
Results: Of 100 admissions eligible for inclusion, 61 received therapeutic GCSF, 59 had complete data and were analysed. Incidences of worsened neutropenia were seen on initiation of GCSF therapy between days 8 to 21. Worsened monocyte count was seen on initiation of therapy between days 10 and 17. Neutrophil recovery and length of admissions were longer in participants who had initial drop in cell count on initiation of GCSF. The small sample size did not yield statistically significant outcomes for dose timing (p=0.674, odds ratio 1.61, (95% C.I. 0.175, 14.809)) or monocyte count (p=0.096, odds ratio 0.413, (95% C.I. 0.146, 1.169)) as predictors of neutrophil recovery. The plotted trends for both neutrophils and monocytes were longer cell count recovery with GCSF dosing between days 7 and 18 as has been reported in simulations.
Conclusions: The data collected showed a clear clustering of incidences of compounded neutropenia supporting the hypothesis that therapeutic GCSF can be detrimental to neutrophil recovery. Further study with power calculation and prospective design is warranted to exclude detrimental clinical practice.