Individuals who receive blood transfusions from donors with undiagnosed cancers are at no higher risk of developing malignant disease than people who receive blood from donors without cancer, according to the results of a retrospective study published in The Lancet last month.

Before donated blood can be used in a clinical setting, it must go through a rigorous battery of tests to ensure that no diseases are passed between the donor and recipient. However, whereas the risk of transmission of infectious agents is well established and appropriate precautions are routinely taken, establishing whether there is also a possibility of transmission of chronic diseases such as cancer through blood transfusions has been more difficult.

There is some evidence to support the theory that cancers might be transmissible through blood. Even if a tumour is too small to be detected, it will shed millions of cells into the circulation every day that may have the potential to establish new malignancies within the donor or blood recipient. Reports of transmission of cancer cells from needles or surgical instruments demonstrate that tumours cells have the capability to be transplanted to, and develop in, healthy recipients. And there is some data to show that transfused patients are at increased risk of cancers, particularly non-Hodgkin lymphoma.

To test some of these ideas, Gustaf Edgren and colleagues set out to investigate whether there is a history of increased cancer diagnoses among individuals that receive blood transfusions from people who donate blood while unaware of their cancers. Using registry data from Sweden and Denmark , the authors created a database from which they identified a group of exposed individuals, who had received donated blood from a person who was diagnosed with cancer less than 5 years after giving blood.

The study population comprised all individuals with no history of malignant disease who had received at le
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Contact: Corinne Hall
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European School of Oncology
20-Jul-2007