Incidence and risk of cancer emergence among patients post-kidney transplantation in Japan.

BACKGROUND

Cancer is one of the most common complications after kidney transplantation and an important cause of mortality. However, no large, nationally representative study has investigated cancer incidence post-kidney transplantation. This study aimed to determine the standardized incidence ratio (SIR) for cancer after kidney transplantation using the National Database of Health Insurance Claims (NDB).

METHODS

We used NDB from April 2013 to March 2022; patients were included if they had been on dialysis for at least one year, were diagnosed with cancer related to post-kidney transplantation, and were prescribed immunosuppressant drugs in FY2014 or FY2015. We defined patients with cancer as those who were coded as ICD-10 for cancer in FY2016 or later. The number of patients and SIRs were tabulated according to the duration after kidney transplantation and cancer type.

RESULTS

The total number of patients was 4484 (males: 2879; females: 1605). The SIRs of all cancers from the first to the seventh year after kidney transplantation were 232/291/235/248/257/187/149, respectively, showing a gradual downward trend over time. The predilection sites of cancer in both men and women were post-transplant lymphoproliferative disease, Kaposi sarcoma, and the kidney.

CONCLUSION

This observational study, which followed over 100 million people, is the first large-scale research to track kidney transplant recipients for under 10 years. It incorporates an unprecedented sample size and uniquely identified short-term cancer risk trends following kidney transplantation.