Dose intensity and survival outcomes with adjuvant FOLFOX for colon cancer.

Abstract

423 Background: Adjuvant FOLFOX chemotherapy for resected high-risk colon cancer is associated with a low risk of febrile neutropenia (FN). Nonetheless, neutropenia is a common cause of dose modification or delay with unknown consequences on outcomes. We examined the effect of neutropenia-related and other dose limiting toxicities (DLT), relative dose intensity (RDI) of oxaliplatin and 5-FU, on relapse-free (RFS) and overall survival (OS) in patients treated with FOLFOX chemotherapy for resected high-risk colon cancer. Methods: A chart review was conducted on patients treated at the British Columbia Cancer Agency with ≥ 1 cycle of FOLFOX chemotherapy for resected stage II or III colon cancer between January 1, 2006 and December 31, 2007. RFS and OS were analyzed by the Kaplan-Meier method and multivariate Cox proportional-hazards models. Results: 114 patients (median age 59.2 years, 43.8% male, 98% stage III, median follow-up 5.2 years) were included. 90% of patients experienced any DLT, while 58% of patients had a neutropenia related DLT. There were no documented episodes of FN. G-CSF was used in 9.6% of patients. Median RDI was 81% and 85% for oxaliplatin and 5-FU, respectively. Oxaliplatin and 5-FU RDI were not associated with RFS or OS when analyzed as continuous variable or categorically (Table). Conclusions: DLTs affect the majority of patients on adjuvant FOLFOX for high-risk colon cancer, but RFS and OS do not appear to be affected by the associated lower RDI of oxaliplatin and 5-FU. [Table: see text]