Normal tissue tolerance to reirradiation

Abstract

As a result of longer survival times, even among patients with incurable malignancies, the prevalence of patients at risk of developing second primary tumours and/or locoregional recurrences in previously irradiated areas might increase. Consequently, the need for additional therapeutic measures providing local control and/or symptom palliation along different lines of treatment has emerged. This has resulted in increasing requests for delivering a second and sometimes even third course of radiation to target volumes within or close to previously irradiated anatomical areas. On the one hand, improved imaging and delivery techniques including image-guided and intensity-modulated radiotherapy might facilitate reirradiation of previously exposed regions of the body. On the other hand, late toxicity is of concern because it often causes serious impact on health-related quality of life. Therefore, knowledge about longterm recovery of occult radiation injury is of utmost importance. This chapter summarises available experimental and clinical data on the effects of reirradiation to various organs.