Basic Clinical Radiobiology 2017

Summary: Radiotherapy 1 • In radical radiotherapy, radiation exposure to non-involved organs and tissues may cause 2 nd cancers several decades later • In adult cancer patients, the risk of radiation-induced 2 nd cancers is much smaller than the risk of recurrent primary cancer • In adults, >90% of 2 nd cancers after radiotherapy are due simply to increased life expectancy after cure of primary • Risk of radiation-induced 2 nd cancers is much greater in younger cancer patients; these increased cancer rates may persist lifelong • Most radiation-induced 2 nd cancers occur in the high-dose volume but also appear in the low dose (<2 Gy) volume