[A Retrospective Study on the Malignancies after Renal Transplantation]

Detection of post-transplant malignant tumors and the analysis of the associated risk factors is important for monitoring the progress after renal transplantation. In this study, we retrospectively examined the medical records of 298 patients who underwent renal transplantation at two facilities in Nagasaki Prefecture (Nagasaki University Hospital and National Hospital Organization Nagasaki Medical Center). Of the 298 patients, 45 (15.1%) patients had developed malignant tumors with 50 lesions. The most common type of malignant tumor was skin cancer (eight patients; 17.8%), followed by renal cancer (six patients; 13.3%), and pancreatic cancer and colorectal cancer, (four patients; 9.0% each). Five patients (11.1%) had multiple cancers, four of whom had skin cancer. The cumulative incidence within 10 and 20 years after renal transplantation was 6.0 and 17.9%, respectively. Univariate analysis identified age at transplantation and administration of cyclosporine and rituximab as risk factors, while multivariate analysis identified age at transplantation and administration of rituximab as independent factors. The administration of rituximab was associated with the development of malignant tumors. However, further investigation is required to establish the association with post-transplant malignant neoplasms.