Re-irradiation for pediatric tumor

Abstract

Radiotherapy is a major component of pediatric cancer treatment for both definitive and palliative purposes. Patients may develop recurrent lesions arising at the irradiated site. These recurrent lesions are sometimes inadequately controlled by other treatments and expected to be controlled further with additional radiotherapy. Recently, re-irradiation, i.e., repeated irradiation of recurrent lesions, has been a clinical issue in pediatric cancer. There are two concerns regarding re-irradiation for pediatric cancer. First, lesions recurring at the site subjected to standard radiotherapy are anticipated to be refractory to radiotherapy. Second, healthy tissue included in the target volume in first-line radiotherapy is anticipated to be affected adversely owing to the accumulated doses conferred by first-line radiotherapy and re-irradiation. Nevertheless, the number of reports of favorable outcomes of re-irradiation for pediatric cancer is increasing. In this report, the author summarizes the evidence for re-irradiation and knowledge of accumulated doses in irradiated healthy organs. Representative diseases and conditions for which re-irradiation is applied are discussed with a focus on re-irradiation efficiency and safety.