Red blood cells supply oxygen to the tissues and organs of the body. Anemia, a decrease in oxygen-carrying red blood cells, is a common complication of cancer and its treatment. On average, nearly one out of every five cancer patients requires a blood transfusion to treat anemia and restore levels of oxygen in the blood. White blood cells help fight infection. A decreased production can leave the patient susceptible to infection that, because of weakened immune systems, can turn deadly.
Platelets are blood components that help control bleeding.
Patients with low platelet counts can bleed to death because the blood doesn't clot properly. There are some risks associated with blood transfusions. A recipient can have a reaction to donor blood. Researchers say there is some evidence that blood transfusion may suppress the patient's immune system and allow cancer to take a stronger hold. Some doctors are administering cytokines to cancer patients as an alternative to transfusions.