Meta-analysis: The use of non-steroidal anti-inflammatory drugs and pancreatic cancer risk for different exposure categories

Background: A better understanding of predictors of risk for pancreatic ductal adenocarcinoma (PDAC) could inform preventive efforts against this lethal cancer. While aspirin (ASA) and non-steroidal anti-inflammatory drugs (NSAIDS) might protect against several gastrointestinal cancers, their role in the development of PDAC remains unclear. Aim: To conduct a systematic review and meta-analysis on the relation between ASA/NSAIDs exposure and the risk of PDAC. Methods: We searched Pubmed, Embase, Scopus, Cochrane database of systematic reviews and reference lists of identified papers and included observational (cohort or case-control) studies and randomized controlled trials examining exposure to ASA and/or NSAIDs and the incidence or mortality of PDAC. We defined three categories (low, intermediate, high), based on exposure duration and dose. Results: Eight studies fulfilled our inclusion criteria (four cohort, three case controls, and one randomized controlled trial studies) enrolling 6301 patients between 1971-2004; all but one study took place in the US. The pooled OR were 0.99 (0.83-1.19), 1.11 (0.84-1.47) and 1.09 (0.67-1.75) in the low, intermediate and high exposure groups respectively, with considerable heterogeneity (I² ranging 60-86%). Sensitivity analysis by ASA use only, study design or sex did not reveal additional important information. Conclusions: This study did not show an association between ASA/NSAIDs and PDAC. The large baseline exposure in controls in North-America may have obscured an association. There is need for additional studies, especially in Europe, to clarify this issue.