Association between hepatitis B or hepatitis C virus infection and risk of pancreatic adenocarcinoma development: a systematic review and meta-analysis.

BACKGROUND: Pancreatic adenocarcinoma (PAC) is an aggressive cancer with a poor prognosis. To date, PAC causes are still largely unknown. Antigens and replicative sequences of oncogenic hepatitis B (HBV) and hepatitis C (HCV) virus were detected in different extra-hepatic tissues, including pancreas. OBJECTIVE: a systematic review and meta-analysis of epidemiological studies assessing PAC risk in patients with HBV/HCV chronic infections. METHODS: In September 2012, we extracted the articles published in Medline, Embase and the Cochrane Library, using the following search terms: "chronic HBV" and "HCV", "hepatitis", "PAC", "risk factors", "epidemiology". Only case/control (C/C), prospective/retrospective cohort studies (PCS/RCS) written in English were collected. RESULTS: four hospital-based C/C studies and one PCS, in HBV-infected patients and two hospital-based C/C studies and one RCS in HCV-infected subjects met inclusion criteria. In these studies HBsAg positivity enhanced significantly PAC risk (RR = 1.18, 95% CI:1.04-1.33), whereas HBeAg positivity (RR = 1.31, 95% CI:0.85-2.02) as well as HBsAg negative/HBcAb positive/HBsAb positive pattern (RR = 1.12, 95% CI:0.78-1.59) and HBsAg negative/HBcAb positive/HBsAb negative pattern (RR = 1.30, 95% CI:0.93-1.84) did not. Relationship between PAC risk and anti-HCV positivity was not significant, although it reached a borderline value (RR = 1.160, 95% CI:0.99-1.3). CONCLUSIONS: HBV/HCV infection may represent a risk factor for PAC, but the small number of available researches, involving mainly populations of Asian ethnicity and the substantial variation between different geographical areas in seroprevalence of HBV/HCV-antigens/antibodies and genotypes are limiting factors to present meta-analysis.