Clinically Important Factors Modifying the Response of Tumors and Normal Tissue to Radiation Therapy

Abstract

The aim of curative radiation oncology is to destroy all tumor cells without producing major damage in normal tissues. As early as 1936 the radiologist Hermann Holthusen related such uncomplicated local tumor control to tumor response on the one hand and normal tissue tolerance on the other (Fig. 1). Holthusen showed that both the probability of eradicating carcinoma of the skin and the probability of developing telangiectasia as a late normal tissue reaction increase as a sigmoid function of radiation dose. At each dose level the probability of uncomplicated local tumor control can be calculated as the product of the probability of achieving local tumor control and the probability of preventing normal tissue damage (Holthusen 1936; Busch 1987).