Prostate cancer and use of non-steroidal anti-inflammatory drugs: systematic review and meta-analysis
adepartment of oncology, bdepartment of surgery, cdepartment of epidemiology and biostatistics; Mcgill University, Montreal, Quebec-Canada
AIM: Animal and laboratory studies suggest that regular use of non-steroidal anti-inflammatory drugs (NSAIDs) may reduce prostate cancer risk. To assess this association, we conducted a systematic review and meta-analysis of observational studies published before Jan 2003. METHODS: We derived summary odds ratios using both fixed and random effects models and performed subgroup analyses to explore possible sources of heterogeneity between combined studies. These analyses comprised calculating summary odds ratios (SORs) for subsets of studies defined by such study characteristics as study design, the outcome examined, drug type, period of recruitment, and geographic region. We also used meta-regression to model the effects of these factors on change in SORs and used graphical and quantitative tests to assess for publication bias. RESULTS: We identified 12 reports (5 retrospective and 7 prospective studies). Most studies of aspirin use reported inverse associations but only two were statistically significant. The summary OR for the association between aspirin use and prostate cancer was 0.9 (95%CI: 0.82-0.99; test of homogeneity P=0.32), and varied from 1.0 for retrospective to 0.85 for prospective studies. Studies from the USA had a higher SOR by an average of 0.32 (95%CI: 0.02-0.62; P=0.04) even after adjusting for study design, length of follow-up, and method of exposure assessment. Studies that measured exposure to a mixture of NSAIDs were less consistent. CONCLUSIONS: These results indicate an inverse association between aspirin use and prostate cancer risk. The current epidemiological evidence and in particular the strong and consistent laboratory evidence underline the need for additional epidemiological studies to confirm the direction and magnitude of the association and to elucidate optimal dosage and timing and duration of the effect. We also suggest approaches to overcome some of the methodological limitations of the reviewed studies.
Paper presented at the International Symposium on Predictive Oncology and Intervention Strategies; Nice, France; February 7 - 10, 2004; in oral session 997 (Chemoprevention).