Incidence of kidney cancer after liver transplantation: a meta-analysis

The purpose of this systematic review and meta-analysis was to investigate the relationship between liver transplantation and kidney cancer. Preferred Reporting Items for Systematic reviews and Meta-Analysis guidelines were followed. PubMed, the Web of Science, and the Cochrane databases were searched for peer-reviewed cohort studies in which standardized incidence of kidney cancer post-transplant was compared to the general population by means of standardized incidence ratio (SIR) with 95% confidence interval (CI). No limits were placed on language or year of publication. A fixed-effects model was used for pooling the data. Of the 937 citations identified from the electronic databases, we included nine cohort studies with 53913 liver transplant patients, a male percentage of 56.8% and a minimum follow-up of 12.4 months and more. The meta-analysis revealed that liver transplant recipients faced a significantly higher risk of developing kidney cancer than the general population with the pooled SIR of 2.02 (95% CI, 1.64-2.50; P < 0.001). No significant between-study heterogeneity was observed (I = 0, Phet = 0.553). On sensitivity analysis after removing the study by Engles et al. with the largest sample size (37 888 liver transplant recipients), the SIR remained stable (SIR 2.75; 95% CI, 1.85-4.10; P < 0.001). Overall, our synthesis of the literature indicates that an increased risk of kidney cancer exists after liver transplantation. Future studies should evaluate the potential risk factors associated with kidney cancer.