Retrospective Comparison of CAPOX and FOLFOX Dose Intensity, Toxicity, and Clinical Outcomes in the Treatment of Metastatic Colon Cancer

Abstract

The treatment of metastatic colon cancer (mCC) utilizes either combination therapies or sequential monotherapy followed by combination therapy in subsequent lines of treatment. Patients often receive therapy consisting of oxaliplatin with intravenous 5-fluoruacil (5-FU) (FOLFOX) or oral capecitabine (CAPOX). A retrospective analysis was performed comparing median dose intensity (MDI), overall survival (OS), progression-free survival (PFS), and toxicity profiles of these two regimens in mCC. One hundred twenty-two mCC patients (pts) received either FOLFOX6 (n = 46) or CAPOX (n = 76). Age, gender, and Eastern Cooperative Oncology Group (ECOG) performance status at diagnosis were balanced between groups. MDI was compared by calculating a percent of target dose achieved in the average cycle for each patient and taking the median of this value. Oxaliplatin MDI trended towards being lower in those treated with CAPOX compared to FOLFOX (87.5 vs 93 %, p = 0.0874), and capecitabine (CA) MDI was significantly lower than 5-FU (82.0 vs 100 %, p < 0.0001). There was a trend to more dose-limiting toxicities (DLTs) in pts treated with CAPOX (68.42 vs 54.35 %, p = 0.1268), and grade ≥ 2 toxicities were more frequent in CAPOX-treated pts (38.16 vs 15.22 % of patients, p = 0.0079). Survival analysis demonstrated trends towards improved median OS (9.86 vs 7.46 months, p = 0.1183) and median PFS (4.34 vs 3.33 months, p = 0.1674) with CAPOX. In multivariate analysis, CAPOX was associated with improved OS (p = 0.0156, hazard ratio (HR) 0.559) and disease-free survival (DFS) (p = 0.0094, HR 0.549). Patients treated with CAPOX received lower doses of oxaliplatin and fluoropyrimidine compared to FOLFOX and had toxicities of higher grade but did not have worsened clinical outcomes.