Understanding Low Platelets

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.