Live Donor Kidneys With Incidental Small Masses May Be Suitable for Transplantation
By Laurie Barclay, MD
Medscape Medical News
December 29, 2009 — Live donor kidneys with incidental small masses may still be suitable for transplantation to high-risk recipients, according to the results of a case series reported in the December issue of the British Journal of Urology International.
Although using this source of kidneys has been considered controversial and high-risk, the investigators decided to try it because of the ongoing shortage of organs from deceased donors and because of low recipient survival while awaiting transplant. Five donors and recipients gave informed consent for surgery after small masses were identified in the donor kidneys.
"This technique is certainly not the magic solution for the organ shortage," coauthor Michael W. Phelan, assistant professor of surgery and director of urological laparoscopy and minimally invasive surgery, Division of Urology, University of Maryland School of Medicine in Baltimore, told Medscape Transplantation.
"However, radiographic technology is improving, and more and more small, incidental masses are being discovered. If all of these small, incidental mass patients are excluded from the donor pool, this could increase the shortage of approved donors."
The goal of this case series analysis was to evaluate transplantation of high-risk kidneys with incidental renal masses, which are occasionally found during the routine evaluation of a living kidney donor, into recipients with limited life expectancy on hemodialysis.
Masses Must Be Small, Organ-Confined
"The eligible donors must present with small, organ-confined renal masses," Dr. Phelan said. "Additionally, all of the recipients in our series were very ill and considered high risk; that is, poor survival on long-term hemodialysis."
During donor evaluation, Dr. Phelan's group identified 5 kidneys with small (<2.3 cm), incidental, enhancing renal masses. Detailed discussion of potential risks led to obtaining informed consent in all 5 donor-recipient pairs. Standard metastatic evaluation was performed in all patients. After laparoscopic donor nephrectomy, the investigators performed a back-table partial nephrectomy and used frozen section analysis to confirm the diagnosis and to ensure that surgical margins were negative before transplantation.
Two of the 5 donor pairs were unrelated, and 3 were genetically related. Age range was 47 to 61 years in the recipients (average age, 54 years) and 38 to 72 years in the donors (average age, 38 years). In addition to end-stage renal disease, all patients had severe hypertension, cardiovascular disease, or other significant comorbidity.
"The most concerning risk [of this procedure] is that of transmitting a cancer from donor to the recipient," Dr. Phelan said. "Given the extensive work-up, this risk is low, but certainly the risk exists and has to be included in the informed consent discussion with the donor-recipient pair. Preoperatively, metastatic work-up is essential in the donor."
Of the 5 identified masses in this series, which ranged from 1.0 to 2.3 cm in diameter, 3 were renal cell carcinomas and 2 were benign angiomyolipomas. Of the renal cell carcinomas, 1 was cystic, 1 was clear cell, and 1 was papillary; these were Fuhrman grades II, II, and III, respectively. The transplanted kidneys showed no signs of long-term complications.
After transplantation, 1 patient developed delayed acute humoral rejection, which was treated appropriately. Periodic imaging was performed both for donor and recipient. Median duration of follow-up was 15 months (range, 1 - 41 months).
At last follow-up, 4 patients were alive and 1 had died from complications after a fall. Cancer-specific survival was 100%, and none of the patients had any evidence of local recurrence at the last follow-up. These findings suggest that it may be acceptable to transplant live donor kidneys with incidental small renal masses into high-risk recipients after careful back-table partial nephrectomy.
"Our series, as well as that of Dr. Nicol and others cited, indicate that small, organ-confined kidney cancers can be transplanted safely if the tumor is excised completely," Dr. Phelan concluded. "Additionally, approximately 40% to 50% of tumors less than 2 cm are benign, even though they are suspicious for cancer on [computed tomography] scans. Certainly, these benign tumors — such as angiomyelolipomas — can be transplanted without question or concern."
A Difficult Dilemma
In an accompanying editorial, David Nicol, MD, from the Renal Transplant Unit and Southern Clinical School, University of Queensland, Princess Alexandra Hospital, in Woolloongabba, Brisbane, Australia, notes that the decision of whether to transplant live donor kidneys with small masses may arise at many transplant centers.
"The donor, their potential recipient, and clinicians involved with the care of both are then confronted with a difficult dilemma," Dr. Nicol writes. "First, the donor who has indicated a desire or willingness to undergo nephrectomy and its associated risk on an altruistic basis for the benefit of the potential recipient needs to reassess their position and decision, based on the radiological findings."
Treatment options for a patient with an incidentally detected renal mass may include nephron-sparing surgery, minimally invasive ablative procedures, nephrectomy, and observation in selected cases. Although nephron-sparing surgery is often preferred over nephrectomy because of its equivalent cancer-specific survival with preservation of overall renal function, additional surgical risks include bleeding, urinary leakage, and wound-related complications.
"By contrast with other patients, the potential live donor has resolved the issue of nephrectomy and its risks, for the benefit of their potential recipient," Dr. Nicol writes.
"In many cases the additional information might not alter their motivation to undergo nephrectomy if this would provide a better outcome for their recipient than remaining on dialysis, and if there was suitable consideration of a deceased donor transplant," he points out. "The recipient might find the diagnosis of a possible cancer challenging, as a consequence of the risks of local recurrence and metastatic disease."
However, these risks may be offset by those associated with continued dialysis and the possibility that subsequent deceased-donor transplantation may not be available.
"Overall, the risks of tumour recurrence after [nephron-sparing surgery] are substantially less than ongoing dialysis, particularly in the elderly or in the context of tenuous access to dialysis," Dr. Nicol concludes.
"Clinicians dealing with the donor and recipient need to recognise the dilemma confronting both individuals, and assist with the final decision by providing a balanced perspective of the risks, acting as advocates for both, as well as respecting their autonomy of choice," he writes. "The age and individual circumstances obviously will influence the advice provided."
The study authors and Dr. Nicol have disclosed no relevant financial relationships.
