Cancer mortality in kidney transplantation

Immunosuppression is associated with an increased risk of cancer in kidney transplant recipients compared to the general population. It is less clear whether standardized cancer mortality ratios (SMRs) are also increased. This study's hypothesis is that SMRs are not increased because of competing risks of death. During the median follow-up of 5.05 years (Q1-Q3: 2.36-8.62), there were 1937 cancer deaths and 36 619 noncancer deaths among 164 078 first kidney-only transplant recipients captured in the United States Renal Data System between January 1990 and December 2004. The observed cancer death rate was 206 per 100 000 patient-years compared to an expected rate of 215 per 100,000 patient-years in the general population. The overall age- and sex-adjusted SMR was only 0.96 (95% CI 0.92-1.00). However, patients <50 years had SMRs significantly greater than unity while patients >60 had SMRs lower than unity. Up to 25% of cancer-related deaths occurred after allograft failure. These findings challenge the notion that cancer is a major cause of premature death in all kidney transplant recipients and has implications for design of cancer prevention strategies in kidney transplant recipients.