Effects of G-CSF vs. No G-CSF on Outcomes Post-Autologous Stem Cell Transplant - A Two-Centre Retrospective Study.

INTRODUCTION In management of patients post-autologous stem cell transplant (ASCT), there continues to be controversy regarding the benefit of granulocyte-colony stimulating factor (GCSF) given post-autologous stem cell transplantation on length of time to engraftment and rates of febrile neutropenia. We conducted a chart review on all patients who received autologous stem cell transplants with follow-up at two tertiary care centres, the Health Sciences Centre in St. John’s, Newfoundland, and Victoria General Hospital in Halifax, Nova Scotia from February 2001 to February 2006.

METHODS Comparison was made between two groups, either receiving (Group A) or not receiving (Group B) planned GCSF (starting 5 days post ASCT) for engraftment purposes. Patients who were not intended to receive GCSF but later received it due to delayed engraftment or febrile neutropenia remained in the non-intervention arm for analysis. Patients were excluded who had CD34+ infusion doses of < 2.5 cells x 10⁶/kg body weight as all these patients received planned GCSF to promote engraftment at both centers. Also, we excluded patients who were transferred from the treatment center (Halifax or St. John’s) to their referring center for post transplant care prior to engraftment as follow up data would not be available for these cases. Primary outcomes included time to neutrophil engraftment and days to hospital discharge. Secondary outcomes included episodes of febrile neutropenia, number of packed red cell and platelet transfusions, days to platelet engraftment and transplant related mortality. Comparison between groups of episodes of febrile neutropenia was performed using Fisher’s exact test and all other variables were analyzed using the unpaired t-test.

RESULTS 215 patients were included, having received autologous stem cell transplants at the above centres from February 2001 to February 2006. There were no significant differences between the two groups in age, sex, or diagnoses. More patients in Group B received etoposide/melphalan conditioning whereas there were more treated with BEAM in group A. Mobilizing regimens also differed significantly, with more patients in the group B receiving GCSF alone. Median time to neutrophil engraftment differed between group A and group B (11 vs. 14 days respectively, p<0.0001). There was a higher incidence of febrile neutropenia in patients in group B (89%) compared with group A (76%, p<0.01). However, there was no significant difference between days to hospital discharge, platelet and packed red cell transfusions, or transplant related mortality. One distinct weakness of the study was in evaluating the duration of hospital stay as this was determined by date of final discharge post transplant and did not take into account delayed admissions or periods of discharge between recurrent admissions for transplant-related issues.

CONCLUSION We observed a significant difference between the rate of febrile neutropenia and duration to neutrophil engraftment in those routinely receiving GCSF as part of post-transplant care vs. those who receive it either not at all or only for delayed engraftment. However, the clinical significance of these findings is unclear, particularly as the time to hospital discharge and the transfusion requirement was the same between the groups. Nonetheless, these results indicate a need for further study in this area, and suggest that more dedicated research into cost-effectiveness of the intervention may be useful.