Assessing alternative dosing strategies for granulocyte-colony stimulating factor (G-CSF) use with FOLFOX6 therapy for treatment of colorectal cancer in a prospective cohort.

Abstract

771 Background: While clinical guidelines recommend an average of 11 injections of granulocyte-colony stimulating factor (G-CSF) per cycle of chemotherapy, few studies support alternative dosing strategies for G-CSF use by cancer type and chemotherapy regimen. Methods: From 2004 to 2013, 63 colon and 47 rectal cancer patients were recruited and monitored throughout the course of their FOLFOX6 therapy. G-CSF use was determined by a clinical pharmacist and tracked every week to ensure patients received an adequate number of injections and were compliant with each cycle. All patients received at least two cycles of G-CSF. Occurrence of neutropenia, febrile neutropenia, and thrombocytopenia were compared between patients receiving four and five injections per cycle. Results: There were 54 males and 56 females with a median age of 56. 104 patients received adjuvant chemotherapy with the remaining six being in the metastatic setting. 83 of 110 (75%) patients experienced no delays after initiation of G-CSF with 67 (61%) of those patients receiving four or five injections per cycle. The remaining 27 of 110 (25%) patients experienced a delay in treatment after at least one cycle of G-CSF completed (15 neutropenic delays, four FN delays, and 12 thrombocytopenic delays). Significantly, only seven of those 27 (26%) patients had a neutropenic delay that occurred as a result of a failed dosing strategy after G-CSF was initiated. Of these seven neutropenic delays, five (71%) were the result of a four dose injection pattern, but none were the result of the five dose injection pattern scheme. All other delays, after at least one cycle of G-CSF (74%), were caused by patients’ non-compliance The overall compliance rate with G-CSF injections was 93%. Conclusions: Only 7 of 110 (6.4%) patients experienced a G-CSF failure. It is recommended that G-CSF be administered on day 4, 6, 8, 10, and 12 of each FOLFOX6 cycle to maintain absolute neutrophil counts and prevent treatment delays.