Understanding Low Platelets
Think of platelets in the same way you'd think of cornstarch or flour when you mix it in a sauce or stew, and it's easy to see why they're so important: They're the clotting factors that make blood thicken and harden. Without them, bleeding becomes unstoppable and suddenly every minor cut or injury becomes dangerous.
Why does cancer make platelet counts drop?
In most cases, it's not the cancer itself but the treatment that causes low platelets. Chemotherapy can make platelet counts fall because it targets cells that grow rapidly. Tumor cells grow and divide quickly, but so do the cells in the bone marrow that produce red blood cells and platelets. Radiation can also cause a low platelet count (also called thrombocytopenia), especially radiation to the pelvic area, because there's a higher proportion of bone marrow in the pelvic bones. But some cancers, particularly lymphoma and leukemia, can lower platelet production if they spread to the bone marrow.
Can low platelet counts be prevented?
There are medications called cell growth factors that can be given along with chemo or radiation to prevent blood counts from dropping. The growth factor that works for low platelets is called oprelvekin (brand name Neumega). There's a risk of side effects with this medication, though, so the doctor will decide whether to prescribe it based on her assessment of the patient's risk of developing a low platelet count. The doctor will also consider whether he has heart problems, because Neumega's side effects include fluid retention and heart palpitations -- both of which can worsen heart conditions. Other side effects include diarrhea and other digestive issues.