Waiting Times for Potential Kidney Transplant Recipients With History of Cancer

I saw a patient in the renal transplant clinic today for evaluation to get onto the kidney transplant list, as he is just around the corner to starting dialysis (actually, he may actually start tonight since his routine labs came back with a K of 6.9...). 

His chronic kidney disease was thought secondary to (a) long-standing hypertension, and (b) a history of bilateral partial nephrectomies for a history of bilateral renal cell carcinomas which were diagnosed about 4 years ago.  

Given this patient's history of cancer and the possibility of recurrence, should this patient be recommended to go onto the kidney transplant list?  How long does he need to wait?  Could the administration of immunosuppresant medications really result in decreased immune surveillance of cancer cells which could potentially result in earlier recurrence of metastatic disease?

  

These are all good questions, and there seems to be a relative lack of data.  According to one seasoned renal transplant doctor I spoke with today, if there is any increased likelihood of cancer in these patients (other than skin cancers or PTLD), it is likely small and not a reason to postpone transplant; the main reason in his mind for waiting to ensure a lack of cancer recurrence is to minimize the likelihood that the patient would need to undergo toxic chemotherapy or a major surgery which could interfere with the graft function.  In addition, there is also the issue of wanting to preserve a scarce resource (donated kidneys) for patients who will benefit from them the longest.  

Nonetheless, the American Transplant Society (ATS) has come up with a list of guidelines for "waiting times" after being treated for various cancers before one should be considered for kidney transplant.  To generalize:  breast, colorectal and melanoma cancers have a recommended waiting time of 5 years unless they are early stage; most other cancers (e.g., renal cell cancer, leukemia, lung cancer, prostate cancer, etc) have a waiting time of only 2 years.  Non-melanoma skin cancers (basal cell, squamous cell) are generally not a reason for delaying kidney transplant as they are generally treatable.