Strategizing the Clone Wars: Pharmacological Control of Cellular Sensitivity to Radiation

The duality of cancer and the duality of chemoradiotherapy. Most cancers require control of both local disease (large sphere) and microscopic metastatic disease (small spheres). Both radiation and chemotherapy can effectively shrink tumors. Radiation that is targeted to specific organ areas can be quite effective at eliminating disease, but it is impractical to irradiate the entire body with doses required to obliterate every cancer cell; microscopic metastases may go untreated (upper panel). In contrast, chemo-therapeutics are generally unable to eradicate primary tumors but are amenable to systemic distribution (lower left). The combination of chemotherapy and radiation is designed to improve local as well as systemic disease. The achievement of both local and systemic control is important to consider as newly developed therapies in one area (e.g., chemotherapeutics, radiation, or surgery) may affect the administration of therapies in another area.