Abstract B26: Pre- and post-diagnostic use of nonsteroidal anti-inflammatory drugs and prostate cancer mortality among men diagnosed with prostate cancer in the NIH-AARP and PLCO cohorts

Background: Prostate cancer is the second leading cause of cancer death in American men, but few modifiable risk factors have been established for prostate cancer progression and survival. Experimental studies have suggested that nonsteroidal anti-inflammatory drugs (NSAIDs) may improve prostate cancer survival through anti-thrombotic and anti-inflammation mechanisms. However, previous observational studies have shown mixed results. No study has examined over-the-counter non-aspirin NSAIDs in relation to prostate cancer survival. Few studies have assessed aspirin use before prostate cancer diagnosis in relation to prostate cancer survival, and whether any etiologically relevant time window of exposure exists remains unclear. Methods: We assessed two cohorts of prostate cancer cases from two large prospective studies in the United States NIH-AARP Diet and Health Study and Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial to investigate associations of aspirin and other nonselective non-aspirin NSAID use before and after prostate cancer diagnosis with prostate cancer-specific and all-cause mortality. Cox proportional hazards models with age as the time metric were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). Results across the two studies were meta-analyzed in a fixed effects model if consistent associations were observed. Results: We did not find statistically significant associations of pre- or post-diagnostic NSAID use with prostate cancer-specific mortality. However, aspirin users versus nonusers five years or more before prostate cancer diagnosis had a 14% (95%CI=0.74 to 1.00) and a 16% (95%CI=0.78 to 0.89) reduced prostate cancer-specific and all-cause mortality when combining the two studies. Post-diagnostic occasional (less than once per day) and daily aspirin use were associated with 17% (95%CI=0.72 to 0.95) and 25% (95%CI=0.66 to 0.86) reductions in all-cause mortality independent of pre-diagnostic use, comparing with no use. Conclusions: This analysis suggests a modest delayed survival benefit of aspirin use before prostate cancer diagnosis and highlights the importance of comorbidity prevention among prostate cancer survivors. Citation Format: Cindy Ke Zhou, Sarah E. Daugherty, Amanda Black, Linda M. Liao, Neal D. Freedman, Christian C. Abnet, Ruth Pfeiffer, Michael B. Cook. Pre- and post-diagnostic use of nonsteroidal anti-inflammatory drugs and prostate cancer mortality among men diagnosed with prostate cancer in the NIH-AARP and PLCO cohorts. [abstract]. In: Proceedings of the AACR Special Conference: Improving Cancer Risk Prediction for Prevention and Early Detection; Nov 16-19, 2016; Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2017;26(5 Suppl):Abstract nr B26.