Robert J. Amdur, MD

Dr. Rich and colleagues present a compelling argument for the manipulation of temporal and spatial treatment parameters in chemoradiation programs. In essence, the authors address the shielding of normal tissues from the effects of cytotoxic agents. With respect to radiotherapy, this can be achieved via physical shielding by computer-generated dose algorithms using elaborate new planning technology (eg, intensity-modulated radiation therapy [IMRT]), chemical shielding with radioprotectants (eg, amifostine [Ethyol]), or temporal shielding by altered-fractionation schemes that exploit the differential alpha/beta ratios between tumor and normal tissue (eg, hyperfractionation).