|MadSci Network: Medicine|
Hi Joan, Theoretically cancer could be "caught" from a blood transfusion if the blood donor had metastatic cancer (cancer that spreads from the initial tumor site). The chances of this occurring are low, though. Less than 1 in 1000 cancer cells in the blood are estimated to survive when cancer metastasizes in a person, so the probability of the cancer cells escaping detection by the immune system of an entirely different person are even less than 1 in 1000. I found the following information on the American Cancer Society website: http://www.cancer.org/docroot/ETO/content/ETO_1_4X_Bloo d_Donati on.asp?sitearea=ETO Cancer Survivors: Blood Donation The risk of getting cancer from a transfusion is extremely small. Even if cancer cells were present in donated blood, the immune system of the person receiving the blood would destroy the cells. A possible exception would be in transfusion recipients with weakened immune systems, which might not be able to fend off the cancer cells. Because of this possibility, in certain cases cancer survivors are not allowed to donate blood for other people. People who were treated for cancer with chemotherapy or hormonal therapy (such as tamoxifen) cannot donate blood. Nor can anyone with leukemia or lymphoma. Cancer survivors who were treated with surgery or radiation therapy may donate blood if they have been cancer-free for at least five years. Potential donors who have had only superficial skin cancers that were removed or destroyed (and therefore have little risk of cancerous cells entering the bloodstream) may not have to wait that long. Ultimately, it's up to the doctor in charge of the donor center whether or not a person is allowed to donate. This is especially true if a potential donor's medical records are not available for review. I hope this helps! Sarah Earley Rensselaer Polytechnic Institute
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