National survey of de novo malignancy after solid organ transplantation in Japan

In Japan, there have been no national surveys on the incidence of de novo malignancy after solid organ transplantation, which is one of the leading causes of death in transplant recipients. A questionnaire was distributed to institutions that perform solid organ transplantation in Japan, and clinical information was collected from patients who underwent transplantation between 2001 and 2010 and who exhibited de novo malignancies. Nine thousand two hundred ten solid organ transplants (kidney, 49.9%; liver, 45.9%; heart, 0.9%; lung, 1.2%; pancreas, 1.9%; small intestine, 0.2%) were performed. Four hundred seventy-nine (5.2%) cases of de novo malignancy were identified. The transplanted organs of the patients included the kidney (n = 479, 54.8%), liver (n = 186, 38.8%), heart (n = 5, 0.1%), lung (n = 18, 3.8%), pancreas (n = 9, 1.9%), and small intestine (n = 1, 0.02%). The most common malignancies were post-transplant lymphoproliferative disorder (n = 87) and cancers of the kidney (n = 43), stomach (n = 41), large intestine (n = 41), and lung (n = 36). This is the first national survey of the incidence of de novo malignancy in Japan. Further study is required to identify the risk of de novo malignancy in organ transplant recipients in comparison to the general population, namely the standardized incidence ratio.