LAUSR

Micro‐Abstract Proton pump inhibitors (PPIs) have been implicated in the impaired absorption of various oral oncologic therapies. Significantly reduced 3‐year recurrence‐free survival rates were seen in our retrospective chart review of stage II‐III colorectal cancer patients who received PPIs concurrently with CapeOx (capecitabine, intravenous oxaliplatin) compared to non‐PPI recipients. No significant differences were seen among FOLFOX‐treated patients (intravenous 5‐fluorouracil, leucovorin, oxaliplatin). Background: First‐line adjuvant chemotherapy options for early‐stage colorectal cancer (CRC) include CapeOx (capecitabine, intravenous oxaliplatin) and FOLFOX (intravenous 5‐fluorouracil, leucovorin, oxaliplatin). Capecitabine is an oral prodrug analog of 5‐fluorouracil, and recent studies have suggested that proton pump inhibitors (PPIs) may detrimentally affect capecitabine efficacy. Conversely, some literature suggests that PPIs may negatively affect CRC itself. To gain insight into the nature of PPIs’ effect on capecitabine and CRC, we investigated their effects on effectiveness of CapeOx versus FOLFOX chemotherapy. Patients and Methods: We conducted a retrospective chart review of 389 patients with stage II‐III CRC who received adjuvant CapeOx or FOLFOX from 2004 to 2013. Information regarding PPI receipt, chemotherapy, and patient outcomes from medical records was analyzed. Results: Three‐year recurrence‐free survival was significantly lower in CapeOx‐treated PPI recipients than non‐PPI recipients (69.5 vs. 82.6%; P = .029). Unadjusted analysis showed that CapeOx‐treated PPI recipients were twice as likely to experience cancer recurrence or death as CapeOx‐treated non‐PPI recipients (hazard ratio = 2.03; 95% confidence interval, 1.06‐3.88; P = .033). FOLFOX‐treated PPI recipients had a non–statistically significant difference in 3‐year recurrence‐free survival versus non‐PPI recipients (82.9 vs. 61.7%; P = .066) and a non–statistically significant difference in recurrence/death (hazard ratio = 0.51; 95% confidence interval, 0.25‐1.06; P = .071). No significant differences were seen in overall survival between groups. Conclusion: Our results suggest PPIs negatively affected recurrence‐free survival in CapeOx‐treated CRC patients and yielded no significant effects among FOLFOX‐treated patients, potentially implicating a pharmacokinetic interaction between PPIs and capecitabine. No overall survival effects were seen. Given PPIs’ widespread use, further studies are required to corroborate our findings.