The present invention is directed to methods for the treatment of cancer with a combination of radiation cerium oxide nanoparticles and at least one chemotherapeutic agent. Cerium oxide nanoparticles (CONPs) are nanometer sized crystals of cerium oxide typically ranging between about one nanometer to about 20 nanometers in longest dimension. The present methods use cerium oxide nanoparticles to enhance radiation induced and chemotherapy induced cancer cell death and also reduce the toxicity associated with radiation therapy and chemotherapy.
