Re-irradiation with stereotactic body radiation therapy (SBRT).

Stereotactic body radiation therapy (SBRT) is a potential treatment option for patients who develop a relapse within or marginal to a previously irradiated volume, but it seems underused because of sparse knowledge on the efficacy and morbidity related to the treatment. Normal tissues often recover some of the damage caused by the primary radiotherapy with time, but the kinetics of recovery is not clearly described in the literature. There is a growing number of publications on SBRT reirradiation, but the literature consists mainly of retrospective cohort studies. The aim of the present paper is to review studies on SBRT reirradiation in various regions where some studies have been published such as the head and neck, lung, liver, pancreas, prostate and spine. Based on the retrospective nature of the literature, the guide-lines provided by this guideline are relatively weak. In some organ systems, some advice on constraints related to reirradiated volumes and doses may be given.