Risk factors for malignancy in Japanese renal transplant recipients.

Background: Among recipients of renal transplants, the incidences of renal cancer and gastrointestinal cancer are higher and that of skin cancer is much lower in Japan than in Europe and North America.

Methods: The risk factors for the development of malignant tumors were examined in Japanese recipients of renal transplants. A total of 556 patients underwent renal transplantation at the Department of Urology, Osaka University Faculty of Medicine between March 1, 1965, and April 31, 2004. Of these patients, 366 were retrospectively studied in whom risk factors potentially related to the development of malignancy could be evaluated on the basis of medical records. The incidence of malignancy, survival rate, and risk factors for malignancy were examined.

Results: The overall incidence of malignancy was 6.8% (25/366 patients). Six of the 25 patients with malignancy died of cancer, but there was no correlation between the occurrence of malignancy and the survival rate (P = .8058, log-rank test). A Cox proportional-hazards model identified treatment with tacrolimus (hazard ratio [HR] = 4.376; 95% confidence interval [CI]: 1.647-11.627; P = .0031) and age at transplantation (HR = 1.562; 95% CI: 1.089-2.240; P = .0155) as risk factors for malignancy.

Conclusions: The results of multivariate analysis suggested that age at transplantation and the use of tacrolimus were independent risk factors for the development of malignancy in recipients of renal transplants.