Reporting their findings in the journal Anesthesiology, the researchers highlight the fact that blood transfusion during certain cancer surgeries is associated with increased cancer recurrence and reduced survival rates, but why this happens is not well understood.
Dr. Shamgar Ben-Eliyahu and his university colleagues say that their study on rats may provide surprising insights that could open doors for important research in humans in the near future.
For their study, the researchers used rat models of leukemia and breast cancer to help determine whether blood transfusion is an independent risk factor for cancer recurrence/progression, and to understand what aspects of the transfusion cause the alleged harmful effects.
"The results of our study clearly indicate that blood transfusion is an independent risk factor for cancer recurrence in the animal models we used," said Dr. Ben-Eliyahu.
"But our study also yielded two surprising findings. First, the storage time of the transfused blood was the critical determinant of harmful effects: fresh blood had no harmful effects. Second, and even more surprising, we found that red blood cells, not white blood cells, caused the effects we observed," the researcher added.
The study's results also contrast the suggestion belief that white blood cells within transfused blood may be responsible for cancer progression, said Dr. Ben-Eliyahu.
He said that there was a co-relation between harmful effects of transfused blood and the amount of time it was stored, with those effects being most significant at nine days storage time or longer.
He added that there seemed to be no difference in harmful effects between transfused blood taken from the same animal or from a different animal.
"The current common approach in cancer patients is to use transfused blood depleted of white blood cells. But we found that removal of white blood cells was ineffective in our setting. Rather, we suggest a different approach: the use of fresh red blood cells for cancer surgeries. For the first time, we have shown in animal models that donor red blood cells, rather than white blood cells or other blood components, can be a critical factor in how blood transfusions affect cancer," he said.
Dr. Ben-Eliyahu said that the findings of their study on mice indicate the need for studies in cancer patients, so that it can be determined whether alterations in blood transfusion practices can indeed improve patient outcomes.