A retrospective analysis of the role of proton pump inhibitors in colorectal cancer disease survival

Background Proton pump inhibitors (PPIS) are a commonly used medication. A limited number of studies have identified a weak-to-moderate association between PPI use and colorectal cancer (CRC) risk, but none to date have identified an effect of PPI use on CRC survival. We therefore postulated that an association between PPI use and CRC survival might potentially exist. Methods We performed a retrospective chart review of 1304 CRC patients diagnosed from January 2005 to December 2011 and treated at the Cancer Centre of Southeastern Ontario. Kaplan-Meier analysis and Cox proportional hazards regression models were used to evaluate overall survival (os). Results We identified 117 patients (9.0%) who were taking PPIS at the time of oncology consult. Those taking a PPI were also more often taking ASA or statins (or both) and had a statistically significantly increased rate of cardiac disease. No identifiable difference in tumour characteristics was evident in the two groups, including tumour location, differentiation, lymph node status, and stage. Univariate analysis identified a statistically nonsignificant difference in survival, with those taking a PPI experiencing lesser 1-year (82.1% vs. 86.7%, p = 0.161), 2-year (70.1% vs. 76.8%, p = 0.111), and 5-year os (55.2% vs. 62.9%, p = 0.165). When controlling for patient demographics and tumour characteristics, multivariate Cox regression analysis identified a statistically significant effect of PPI in our patient population (hazard ratio: 1.343; 95% confidence interval: 1.011 to 1.785; p = 0.042). Conclusions Our results suggest a potential adverse effect of PPI use on os in CRC patients. These results need further evaluation in prospective analyses.