Cigarette smoking increases the risk of mortality from liver cancer: A clinical-based cohort and meta-analysis

Background and AimAlthough the influence of cigarette smoking on the incident risk of liver cancer has been determined, the association between smoking and liver cancer mortality remains uncertain. MethodsWe searched Pubmed, EmBase, and Web of Science databases to obtain eligible studies. Hazard ratio (HR) value and 95% confidential intervals (CI) were pooled by using a random-effects model, and dose-response analyses were conducted to quantify associations between smoking and mortality from liver cancer. ResultsA total of 27 articles involving four million participants from seven countries by retrieval (published 1986-2014) were finally included. Pooled HR values for liver cancer mortality was 1.45 (95% CI: 1.33-1.59), 1.22 (95% CI: 1.11-1.34) and 1.16 (95% CI: 1.01-1.32) for current, former, and ever smokers, respectively, when compared with nonsmokers. The risk increased by 7.1% (95% CI: 1.4-13.2) for per additional 10 cigarettes per day and by 5.2% (95% CI: 0.02-11.2) for per additional 10 pack-years. In our population recruiting 597 patients with liver cancer, smoking status was further identified as a significant determinant factor of tumor size and serum level of gamma-glutamyl transpeptidase, but not a significant prognostic factor. ConclusionsCigarette smoking, especially current smoking, significantly increased mortality risk from liver cancer.