Impact of Endogenous and Exogenous Factors on Radiation Sequelae

Abstract

The aim of curative radiation therapy is to achieve uncomplicated local tumor control, that is to destroy all clonogenic tumor cells without producing major damage to surrounding normal tissue. This principle was illustrated by Hermann Holthusen, who used data on control of skin carcinoma and development of telangiectasia as an indicator of late-occurring normal tissue damage (Fig. 1). Both the probability of local tumor control and the development of normal tissue damage increased as sigmoid functions of radiation dose. The probability of uncomplicated local tumor control at each dose level was given as the product of the probability to achieve local tumor control and the probability of preventing normal tissue damage (Holthusen 1936; Busch 1987).