Worse Transplant Outcomes With Preexisting Malignancies in Remission

By Will Boggs MD

May 02, 2016

NEW YORK (Reuters Health) - Patients with pretreatment malignancies (PTM) in remission fare worse after solid-organ transplants than do their peers without PTM, researchers from Canada report.

"These patients are at higher risk of adverse outcomes, but the risk is not so high that transplantation should be contraindicated in this group," Dr. Nancy N. Baxter from the University of Toronto, Canada, told Reuters Health by email. "Importantly, we also found that patients with pretransplant malignancies had a higher risk of developing a second cancer as compared to transplant patients without a previous malignancy, so tailored screening and management strategies may be of use."

PTM in remission is a relative contraindication to solid-organ transplantation because of the concern that immunosuppression to prevent graft rejection might allow the growth of dormant malignant cells in these patients.

Dr. Baxter's team undertook a systematic review and meta-analysis of 33 articles in order to assess the risks of all-cause mortality, cancer-specific mortality, and posttransplant de novo malignancy in solid-organ transplant recipients with PTM when compared with recipients without PTM.

All-cause mortality was significantly higher in patients with PTM than in those without PTM (hazard ratio, 1.51), with similar increases after kidney transplant (HR, 1.53) and after non-kidney transplant (1.61), the researchers report in Transplantation, online April 20.

Cancer-specific mortality was increased 3.13-fold among patients with PTM, and the incidence of posttransplant de novo malignancy was 92% higher, again with similar increases after kidney and non-kidney transplants.

"The selection of transplant candidates with a history of malignancy is currently based on their risk of cancer recurrence," Dr. Baxter explained. "Minimum times in cancer remission are required to list these patients for transplantation. However, the effect of prolonging the wait time for transplantation on overall outcomes for these patients has not been examined. Some patients at low risk of cancer recurrence may wait unnecessarily and be at risk of dying without transplantation during this time period."

"While our study does not imply selection criteria should change, a more individualized risk-based approach might enable low-risk patients to benefit from transplantation without excessively prolonged waits," she said.

"As the age of transplant candidates rises, the number of patients with pre-transplant malignancy needing transplantation will likely increase," Dr. Baxter said. "In previous research we found that in 2010 as many as 1 in 14 patients undergoing transplant in Ontario had a pre-transplant malignancy. We need better strategies to assess and minimize risk for these patients."

"All patients undergoing transplantation irrespective of cancer history are at increased risk of developing and dying from cancer as compared to the general population - cancer is a leading cause of death in transplant patients," Dr. Baxter concluded. "We need more research in the areas of prevention and early detection to avoid adverse cancer outcomes for these patients."

Dr. Josep Maria Campistol from Hospital Clinic in Barcelona, Spain, who has studied pre- and posttransplantation cancer, told Reuters Health by email, "We always are selective when including patients in the waiting list for organ transplantation, especially with cancer backgrounds."

"The main message is prevention," he said. "Cancer is an important disease in the transplant population, so we have to be cautious."

Dr. Campistol, who was not involved in the new work, said it's important to consider the choice of immunosuppressive treatment in patients with PTM.

SOURCE: https://bit.ly/1T9yqIM

Transplantation 2016.