Post-transplant malignancy: a burdensome complication in renal allograft recipients in Korea.

Cancer has been a serious complication of kidney transplantation ever since the outcome of this procedure improved. The incidence of cancer among kidney transplant (KT) recipients is increasing, and these patients have a higher risk of developing cancer than the general population. The present retrospective cohort study compared the cancer rate of kidney recipients in a single transplantation center in Korea with that in healthy Korean individuals using the standardized incidence ratio (SIR). The medical records of all 2365 patients who underwent renal transplantation between 1989 and 2009 were reviewed retrospectively. During the study period, 136 renal allograft recipients developed 140 malignancies. The cumulative cancer incidence one, five, 10, and 15 yr post-transplantation was 0.60%, 3.24%, 5.69%, and 8.90%, respectively. Non-Hodgkin lymphoma (NHL) and thyroid cancer were the most common cancers after renal transplantation, occurring significantly more frequently than in the general Korean population. The SIR of all cancers was 1.9 (women: 2.4; men: 1.6). Comparison with similar studies in Korea and other countries suggests transplant center-related differences dictate post-transplant malignancy incidence more strongly than ethnic or geographic factors. Early surveillance programs for de novo malignancies after kidney transplantation focusing on kidney-transplantation-related tumors and postoperative time period should be established.