[en] Risk-benefit considerations underlie all patient management decisions and pose a complex philosophical and practical problem. Theoretical curves describing the probability of tumor control and the risk of developing major complications are plotted as a function of radiation dose. Both curves follow a sigmoid distribution with the separation between them representing the therapeutic gain. Treatments that widen this separation improve therapeutic gain. If both curves are shifted equally in the same direction, however, there is merely a dose modification effect. The obvious difference between treatments A and B is improved tumor control with B but at a substantially higher risk of complication. Unfortunately, this graphic display does not completely describe the therapeutic problem. In addition to the risk of major complications, the probability of effectively treating them is an integral part of the initial management decision. If, for example, a treatment failure cannot be salvaged by retreatment but the complication is manageable, a dose that maximizes tumor control (program B) should be used and the higher complication rate accepted. Under these circumstances, the worse complication of treatment is failure to control the tumor. Conversely, the risk of developing an untreatable and life-threatening complication necessitates the use of a radiation dose that minimizes the complication (program A), despite diminished probability of tumor control