Abstract 4812: HCV infected elderly are at excess risk of pancreatic cancer: a population based SEER-Medicare study.

Abstract

Abstract Background: Pancreatic cancer is uncommon, however, it is a fatal cancer that ranks the fourth in mortality in United States. Risk factors of pancreatic cancer include infections, smoking, hormonal, alcoholism, genetic, and environmental factors. Pancreatitis is one of the risk factors of pancreatic cancer which is also, one of the observed extrahepatic manifestations of hepatitis C virus (HCV) infection. HCV infection mortality and morbidity are increasing; therefore it is important to understand the relationship between HCV infection and pancreatic cancer and the role of HCV-related pancreatitis. Methods: We used the Surveillance, Epidemiology, and End Results (SEER) Medicare linked (SEER-Medicare) database to employ a population-based nested case control study among United States elder. The study included 29,892 pancreatic cancer cases and 100,000 controls. In this study, we calculated adjusted odds ratios (ORs) and 95% confidence intervals (CI) using unconditional logistic regression. Models were adjusted for the matching variables including age, sex, and calendar year. To examine the hypothesis that pancreatitis is in the causal pathway between HCV and pancreatic cancer; and therefore, is a mediator (intermediate endpoint), we used mediation modeling to calculate the percentage of the total effect of HCV that is mediated by pancreatitis. Results: HCV infection was reported in 0.42% pancreatic cancer cases and 0.32% controls. Pancreatitis was observed in 6.2% of HCV infected, and 1.4% non-HCV infected. Pancreatitis was reported in 2.6%, and 1.4% of cancer and controls respectively. Adjusting for matching variables, HCV infection was associated with higher odds of pancreatic cancer [OR (95% CI); 1.36(1.10-1.68)]. In the mediation modeling, pancreatitis significantly mediated the HCV effect, such that 11.4% of HCV effect was mediated by pancreatitis. Conclusion: HCV is a risk factor of pancreatic cancer. HCV effect is mediated in part by pancreatitis. Further studies are warranted to understand the various mechanisms that might explain the excess risk of pancreatic cancer among HCV infected individuals, and to determine the effect of HCV treatment on pancreatic cancer risk. Citation Format: Fatma M. Shebl. HCV infected elderly are at excess risk of pancreatic cancer: a population based SEER-Medicare study. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4812. doi:10.1158/1538-7445.AM2013-4812