Pre-Transplant Cancers Might Be Overlooked

LAKE LOUISE, Alberta—Many cancers found after kidney transplantation might have been present prior to surgery and possibly could have been detected during the pre-transplant workup, according to results from a new study.

In a group of 3,524 kidney transplant recipients in Quebec, 36 neoplasias were detected within a year of surgery. Of these, 16 (44%) may have been present before transplantation and could have been detected during the routine pre-transplant workup. Another 12 (34%) were post-transplant lymphoproliferative disease caused by immunosuppression. The remaining eight (22%) may have been present before transplantation but would not have been detected because they were in areas that are not routinely covered by pre-transplant screening, for instance ear-nose and throat cancers.

“The problem is that transplant candidates are screened once at the time of evaluation and put on the list to wait, and there are long and unpredictable wait times,” said Héloise Cardinal, MD, who presented the results at the 2013 annual meeting of the Canadian Society of Transplantation. “There should theoretically be an update in the cancer screening when patients have been waiting many years on the list, but implementing this is  not always easy, because the patients are usually followed in their dialysis centers far from the transplant center.”

Dr. Cardinal, of the Centre Hospitalier de l'Université de Montréal, analyzed and presented the review of first-kidney-transplant recipients in five adult kidney-transplant centers in Quebec from January 1985 to January 2009. They excluded individuals who received another organ along with a kidney or who died or rejected the kidney within the first month of the surgery.

The average age among the 3,524 patients was 47 years, 91% were Caucasian, and 64% were men. Their median time on dialysis before transplantation was 22 months (range 11-38). Forty percent had glomerular disease and 14% had polycystic kidney disease.

Furthermore, 26% had anti-lymphocyte induction therapy, 22% had anti-CD25 induction therapy, half had tacrolimus/mycophenolate mofetil/prednisone, and 25% had cyclosporine/prednisone immunosupression.

Post-transplant cancers developed in 350 patients. Of these, 17% were renal cell carcinomas (with 8.3% occurring in the graft), 13% were in the prostate, 13% were in the lung, 10% were post-transplant lymphoproliferative disorders, 7% were in the breast, and 6% were colorectal.

Thirty-six were detected within a year of the transplant surgery.

“An interesting question is whether these early lesions were present and missed before transplant, or if they truly did develop after transplantation because of increased immunosuppression,” Dr. Cardinal said.

Pre-transplant cancer screening includes mammography in women after age 50 or earlier if they have a positive family history; colonoscopy after age 50, or earlier if there is a strong positive family history; a Pap test and gynecologic exam; and a digital rectal examination plus PSA testing in men over 50. Most centers also perform an abdominal ultrasound to look for renal cell carcinoma because they develop more frequently in dialysis patients than in the general population, Dr. Cardinal said.

Overall, patients who were diagnosed with cancer after transplantation often were given a reduced immunosuppression regimen, even those with neoplasms that are not usually associated with immunsuppression such as breast and prostate cancer. Fifty percent of those who developed cancer died within five years.

“Although reducing the burden of immunosuppression is clearly useful in some cancer types, for instance, post-transplant lymphoproliferative diseases, we don't know if in cancer types that are not strongly linked to immunosuppression, this is effective or not, or if conversion to rapamycin in these cases would help, so it is food for thought and future studies,” Dr. Cardinal said.

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