Influence of Current and Previous Smoking on Cancer and Mortality After Kidney Transplantation

Background Evidence is limited regarding the effect of stopping smoking before kidney transplantation. Methods Collaborative Transplant Study data from 46 548 recipients of first kidney transplants (1995-2012) were analyzed to 10 years after transplantation. Results Compared with patients who had never smoked (n = 31,462), patients who stopped smoking before transplantation (n = 10,291) only had a modestly increased risk of all-cause graft failure (hazard ratio [HR], 1.1; 95% confidence interval [95% CI], 1.0-1.1; P < 0.001) or death (HR,1.1; 95% CI, 1.0-1.2; P < 0.001) and a similar risk of death-censored graft failure (HR,1.0, 95% CI, 1.0-1.1; P = 0.19), but a 40% increase in death from malignancy (HR, 1.4; 95% CI, 1.2-1.7; P < 0.001). The risk of events was generally markedly higher in patients who continued to smoke (n = 4795) versus those who had stopped. For tumors of the lip, oral cavity and pharynx, digestive organs, respiratory tract, female genitalia and urinary tract, HR values increased significantly from never-smoked to former smokers to current smokers. The risk of respiratory tumors or cervical cancer was approximately halved when smoking was stopped versus continued. Conclusions This large series provides clear evidence that patients who stop smoking before transplantation experience substantial benefits, including a substantial reduction in certain types of malignancy.