Cancer risk in patients receiving renal replacement therapy: A meta-analysis of cohort studies

It has been reported that patients receiving renal replacement therapy (RRT), including dialysis and kidney transplantation, tend to have an increased risk of cancer; however, studies on the degree of this risk have remained inconclusive. The present meta-analysis was therefore performed to quantify the cancer risk in patients with RRT. Cohort studies assessing overall cancer risk in RRT patients published before May 29, 2015 were included following systematic searches with of PubMed, EMBASE and the reference lists of the studies retrieved. Random-effects meta-analyses were used to pool standardized incidence rates (SIRs) with 95% confidence intervals (CIs). Heterogeneity tests, sensitivity analyses and publication bias assessment were performed. A total of 18 studies including 22 cohort studies were eventually identified, which comprised a total of 1,528,719 patients. In comparison with the general population, the pooled SIR for patients with dialysis including non-melanoma skin cancer (NMSC), dialysis excluding NMSC, transplantation including NMSC, transplantation excluding NMSC and RRT were 1.40 (95% CI, 1.36-1.45), 1.35 (95% CI, 1.23-1.50), 3.26 (95% CI, 2.29-4.63), 2.08 (95% CI, 1.73-2.50) and 2.01 (95% CI, 1.70-2.38), respectively. The cancer risk was particularly high in subgroups of large sample size trials, female patients, younger patients (age at first dialysis, 0-34 years; age at transplantation, 0-20 years), the first year of RRT and non-Asian transplant patients. A significant association was also found between RRT and the majority of organ-specific cancers. However, neither dialysis nor transplantation was associated with breast, body of uterus, colorectal or prostate cancer. Significant heterogeneity was found regarding the association between RRT and overall cancer as well as the majority of site-specific cancer types. However, this heterogeneity had no substantial influence on the pooled SIR for overall cancer in RRT according to the sensitivity analysis. Compared with the general population, RRT patients have a significantly increased risk of overall cancer and the majority of specific cancer types, particularly Kaposi sarcoma (KS), lip cancer and NMSC in patients subjected to kidney transplantation and cancer of the thyroid gland and kidney as well as myeloma in dialysis patients. Considering the high heterogeneity encountered, further high-quality studies are required.