Effects of proton pump inhibitors (PPIs) on FOLFOX and XELOX regimens in colorectal cancer (CRC).

Abstract

621 Title: Effects of Proton Pump Inhibitors (PPIs) on FOLFOX and XELOX Regimens in Colorectal Cancer (CRC) Background: First-line adjuvant chemotherapy options for stage II-III CRC include XELOX (capecitabine (cape), oxaliplatin) and FOLFOX (oxaliplatin, leucovorin, 5FU). Cape is an oral 5FU prodrug, and recent studies suggested that PPIs may detrimentally affect cape efficacy. Conversely, some literature posits that PPIs may negatively impact CRC itself. Our primary objective was to compare 3-year recurrence-free survival (RFS) rates between XELOX-treated PPI-users and non-PPI users, and FOLFOX-treated PPI users and non-PPI users. Our main secondary objective was to compare overall survival (OS). Methods: We conducted a retrospective chart review of 389 stage II-III CRC patients (pts) who received adjuvant XELOX or FOLFOX from a tertiary cancer center in Alberta, Canada between 2004-2013. Information regarding PPI use, cancer treatment, and pt outcomes were gathered and analyzed from pharmacy databases. Results: 23.4% of XELOX-treated pts and 28.0% of FOLFOX -treated pts used PPIs concurrently with treatment. 3-year RFS was significantly lower in XELOX-treated PPI pts than non-PPI pts (69.5 vs. 82.6%, P=0.029). Unadjusted analysis showed that XELOX-treated PPI pts were twice as likely to experience cancer recurrence or death as XELOX-treated non-PPI pts (HR 2.03, P=0.033). FOLFOX-treated PPI pts had a non-significant increase in three-year RFS versus non-PPI pts (82.9 vs. 61.7%, P=0.066), and no significant difference in recurrence or death (HR 0.51, P=0.071). No significant differences were seen in OS. Conclusions: Our results suggest that PPIs negatively impacted RFS in early-stage XELOX-treated CRC pts, and yielded no significant effect amongst FOLFOX-treated patients. Further studies are required to corroborate our findings. [Table: see text]