Transplanting kidneys with small renal masses: a new source of renal allografts

The number of publications on transplanting kidneys with small renal masses is steadily growing. There are several transplant centers worldwide with organized programs of transplanting such kidneys. Nevertheless, despite growing number of reports this practice remains controversial. The existing guidelines for kidney transplantation give controversial recommendations concerning transplantation of the kidneys with renal masses. There are arguments in favour as well as against this policy. Importance of the subject is emphasized by calculations showing that about 3000 kidneys with tumors could be transplanted in the United States annually. Based on the results reported in the literature the risk of occurrence of de novo graft tumor is extremely low and varies from 0.24% to 0.46%. A risk of getting a transmitted cancer is even lower and reported as 0.015-0.2%. The patient and graft survival rates of these kidneys are comparable to that of the standard criteria deceased and living transplant. More studies with higher number of patients are needed to prove the functional and oncological safety of this practice.