The science…or not behind deferrals of blood donors with a history of cancer

Background: In the United States (US), each blood center's medical director sets policy for donors with a cancer history. Study Design and Methods: A subgroup of America's Blood Centers' (ABC) Scientific, Medical, and Technical Committee developed a survey to measure the determination of eligibility, policies for deferral and/or lookback when a donor reports a current diagnosis or history of cancer. A 31-question survey was sent to 47 ABC blood centers in North America via email. Survey results were compiled and literature evaluating the risk of cancer transmission by transfusion was reviewed. Results: Responses were received from 37 centers (79%). Donors with a history of carcinoma or sarcoma who had completed treatment were accepted at 73% of centers with no further deferral. Donors with a history of leukemia or lymphoma were permanently deferred at 76% of centers. Donors with a myelodysplastic or myeloproliferative syndrome were deferred permanently at 86% of centers. Handling of donors with high white cell counts varied. Donors with cancer not in active treatment (i.e., prostate cancer) were subject to various deferrals. Center response to post-donation reports of cancer vary widely. Literature review yielded no evidence of transfusion-transmitted cancer. Conclusion: Cancer deferral policies vary widely among blood centers, and are not generally based on evidence, but on some aspect of the precautionary principle. As the donor population ages and so becomes more at risk of cancer, this approach may further reduce the available donor pool.