There is no evidence to suggest that blood transfusions from donors with undiagnosed cancer are associated with increased risk of cancer among recipients. The findings are reported in an Article in this week's edition of The Lancet.
Professor Olof Nyrén and Gustaf Edgren, Karolinska Institutet, Stockholm, Sweden together with Professor Mads Melbye and Dr Henrik Hjalgrim from Statens Serum Institut, Copenhagen, Denmark organised a binational project to study the cancer incidence among patients who received blood from donors deemed to have a subclinical cancer at the time of donation.
Using data from all computerised blood bank registers in Sweden and Denmark that were gathered between 1968 and 2002, the researchers identified 1.13 million blood donors and 1.31 million transfusion recipients. Out of the more than 350,000 recipients eligible for the analysis, just over 12,000 (3%) were exposed to blood products from precancerous donors. The recipients were followed for as long as 34 years.
The authors say: "Continuous attention to transfusion safety has reduced the risk of transfusion-transmitted disease to a current record low. However, although most infectious complications have been relatively easy to identify, possible transmission of chronic diseases with unknown causes and long induction or latency periods has been far more difficult to address."
They conclude: "Our data provide no evidence that blood transfusions from precancerous blood donors are associated with increased risk of cancer among recipients compared with transfusions from non-cancerous donors."
In an accompanying Comment, Dr Garth Utter, Department of Surgery, University of California, Davis, Sacramento, California, USA, says: "Blood is an immensely complex and biologically active substance. Although the potential for standard allogeneic blood transfusion to save lives is incontrovertible, our understanding of the full consequences of transfusion is rudimentary."
He adds: "With their thoughtful analysis of a large and relatively complete dataset, Edgren and colleagues have taken an important stride forward in evaluating one of these potential long-term risks of blood transfusion."