麻豆传媒

Despite concerns about transmission of cancer from deceased organ donors with brain tumors to recipients, results from a cohort study in the U.K. showed that this risk was lower than previously thought.

Among 83 post-transplant malignancies that occurred over a median 6 years in 79 recipients of transplants from donors with brain tumors, none matched the histological type of the donor brain tumor, reported George H.B. Greenhall, MBChB, of the Organ and Tissue Donation and Transplantation Directorate at the National Health Service in England, and co-authors.

Compared with matched controls who received transplants from donors without brain tumors, transplant survival was equivalent, though kidney, liver, and lung utilization were lower in donors with high-grade brain tumors, they noted in .

"No transmissions occurred despite many donors having high-grade tumors or undergoing prior surgical intervention, both of which are considered as increasing the risk of transmission," Greenhall and colleagues wrote. "Results suggest that donors with brain tumors were a source of good-quality organs, as evidenced by favorable risk markers and excellent transplant outcomes."

They also noted that while active cancers usually prevent organ donation, organs from patients with primary brain tumors are generally more accepted because these cancers rarely spread beyond the central nervous system, lowering the risk of cancer transmission.

The 10-year survival of transplants from donors with brain cancer was 65% for single kidney transplants, 69% for liver transplants, 73% for heart transplants, and 46% for lung transplants.

Controls matched for characteristics like donor and recipient age, sex, type, and urgency had similar transplant survival.

Greenhall said in an email to 麻豆传媒 that the researchers hoped to address gaps in previous research -- like the influence of prior treatment and tumor histology -- in a large-scale study, and were able to do so with the better data available.

He added, "there are stark differences in the guidelines on donors with brain tumors in the U.K. and the U.S.A., with U.S. guidance quoting a much higher risk of transmission for some tumors. We wanted to clarify this further."

"While no one would suggest that transplantation from a donor with brain tumors is risk-free, guidelines need to strike a balance between enabling transplant opportunities and defining risk," said Greenhall. "It may be possible to update guidance in light of the accumulated evidence."

Despite a push to increase the donor pool for those awaiting transplants, "malignancy has been a relative contraindication for donors to be considered for organ transplant because of data showing poor outcomes from an era when organs from deceased patients with cancer were commonly used and when staging for cancer by imaging was poor," wrote Yuman Fong, MD, of the City of Hope Medical Center in Duarte, California, in an .

"These findings demand a reexamination of transplant using organs from patients with brain cancer," Fong added. Because cancer imaging is more sensitive than ever, "it is highly likely that these staging techniques for ruling out metastatic disease contributed to the favorable outcomes seen in this study."

Greenhall and team used linked data on deceased donors and solid organ transplant recipients with valid national patient identifier numbers from the U.K. Transplant Registry, the National Cancer Registration and Analysis Service in England, and the Scottish Cancer Registry from 2000 through 2016.

They included a total of 282 deceased donors with primary brain tumors (median age 42, 55% women) and 887 transplants from them, 778 of which were analyzed. Overall, 153 donors had low-grade brain tumors, 95 had high-grade tumors, and 34 had tumors of unknown grade.

In total, 202 donors had undergone neurosurgical procedures before organ donation, including tumor resection, external ventricular drain insertion, shunt insertion, and biopsy alone.

Intracranial lymphoma, spinal cord tumors, and cranial nerve tumors were excluded. Four age- and sex-matched controls were selected randomly for each transplant from a donor with a brain tumor.

Greenhall and co-authors noted that their study could be limited by less accurate early data from cancer registries, the 10% of transplants from patients with brain tumors they had to exclude from Wales and Northern Ireland, some tumors with "uncertain histology," and the lack of confirmation of tumor origin by genetic analysis, which meant they couldn't "exclude cancer transmission with complete certainty."

They also acknowledged that their risk stratification method may have been oversimplified, and that selection bias could have played a role in survival and utilization analyses.

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