Discussion
Solid organ transplantation
from donors with existing or past cancers has been an absolute or relative contraindication due to the chance of cancer
cells being transferred to the recipient. Donor Origin Cancer(DOC) is still an
area to be better understood. It is important to notice that even without a
prior history of neoplasm, the chance of DOC is 0.06%. Though the exact incidence
of donor-origin Renal Cell Carcinoma(RCC) is unknown, the potential for safely
transplanting kidneys with Small Renal Mass(SRM) has been described by Stubenbord
et al, as early as 1982. In the case of well-differentiated RCC, the risk
of transmission was assessed as minimal (<0.1%) in tumors less than 1.0 cm
in size or low (<2%) for tumors between 1.0 cm to 4 cm in size. On a
case by case basis, the risk of tumor transmission
should always be balanced against the benefit of the transplant for recipients.
In our case, the indeterminate lesion seen on
advanced radiological images during donor evaluation prompted us to proceed with
resection of the lesion. Unbiased specialist opinion from the of the Urologist and
Oncologist was sought and the potential donor underwent surgical excision of
the tumor. The histopathology report confirmed the excised tumor as RCC of less
than 2 cm size, low grade clear cell type variant with low malignant potential
and clear margins. Our prospective donor had no prior knowledge of harbouring a
renal tumor and the diagnosis of RCC in her came as a unexpected jolt, arising
many ethical questions on possible donation. As per Flechner & Campbell, the
living kidney donor found to have an incidental renal mass should be first referred
to a urologist for the appropriate oncological management of SRMs and then only the discussion about living
donation should be entertained. Accordingly, excision of the RCC was
ultimately the best treatment for our potential donor which was indeed
curative.
The decision to continue with
renal transplantation in this circumstances is complex. The initial intent of
the individual to donate a kidney becomes questionable. Consideration of donor
demographics, total renal function, co-morbidities, psychosocial factors and
relationship to the recipient becomes imperative. Some individuals are strongly
motivated to donate, as in our case where the wife's altruistic act towards her
husband remains understated. Probably the only question that remains relevant
to them is the risk of recurrence in the recipient and their own chances of
developing another kidney cancer in the remaining kidney. To answer these
question, we did a thorough literature search and found that Cristea et al have
analysed 30 data sets showing that a total of 147 tumorectomized kidneys have
been transplanted so far. Most excised tumors were RCC (81%), mean tumor size
was 2 cm and nucleolar/Fuhrman grade
I–II (93%) with mean follow-up of 39.9 months. Only 1 local tumor recurrence occurred
in a patient 9 years after
transplantation, demonstrating a recurrence rate of 1.4% in the recipients. The
5-year patient and graft survival were 92% and 95.6%, respectively. Based on
the available data, various governing bodies recommend that donor kidney can be
used for transplantation after excision of RCC (clear-cell type) if size
<2–4 cm, nucleolar grade ≤II with clear surgical margins. In a recent
report of 28,556 Scandinavian patients
with RCC, the 20-year cumulative incidence of metachronous RCC was 0.8%.
Using the US SEER database the incidence of metachronous RCC among 43,483
patients was 0.4% up to 10 years. This knowledge enabled us to provide sufficient
evidence to the recipient and donor of their lower chances of tumor recurrence
and good graft function by accepting the tumorectemized kidney.
With the institutional ethics
committee at the helm of affairs, we conducted several counselling and
consenting session at appropriate stages to clearly outline the risk of cancer
recurrence and transmission, the surgical complications and the need for
ongoing post-transplant surveillance for RCC recurrence, in addition to the
standard post-transplant follow-up. Only after confirming the willingness from
the donor and recipient separately, the decision to proceed with the
transplantation was made. Concurring with the recommendations and robust
evidence from available literature, we were able to carry out the renal
transplantation.
We
used the contemporary immunosuppression in the kidney transplant recipient
consisting of a calcineurin inhibitor
(CNI), an anti-proliferative agent(MMF) and a systemic corticosteroid since
there are no definitive guidelines for use of
mTOR inhibitors in reducing the risk of RCC recurrence.
The recommendation for follow-up
suggest a conservative approach, comprising of ultrasound, chest x-ray,
abdominal CT and laboratory investigations (complete blood count, renal
function test, liver function test and calcium). In line with this, our
follow-up data is limited to 3 months post transplantation. Both the recipient
and donor are doing well with normal renal functions and no evidence of
recurrence by the imaging studies.
