{"entity":{"id":"re-irradiation","kind":"term","name":"Re-irradiation","aka":["reirradiation","re-irradiated","repeat radiotherapy","second course of radiotherapy","in-field recurrence","previously irradiated"],"tldr":"Giving radiotherapy again to a region that has already been treated, once thought impossible because normal tissues remember the first dose. Modern precision techniques make it feasible in selected patients.","summary":"Recurrent head and neck cancer, glioma, rectal cancer and spinal metastases are the main settings. Cumulative dose to critical structures (spinal cord, brainstem, bowel) limits what can be given, so SBRT, IMRT, protons and brachytherapy, which spare surrounding tissue, are preferred, and the interval since the first course matters as some recovery occurs. Toxicity (necrosis, fistula, carotid blow-out in the neck) is higher than for first treatment, so re-irradiation is often combined with or replaced by surgery or systemic therapy when possible.","asOf":"2026-09-09","wikipedia":"https://en.wikipedia.org/wiki/Radiation_therapy","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Radiation_therapy"}],"tags":[],"related":["gray-unit","sbrt-term","brachytherapy-term","salvage-therapy"],"cancers":["head-and-neck","glioblastoma","colorectal"],"sections":["radiation"],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":[],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"category":"Treatment jargon"},"route":"/terms/re-irradiation/","neighbours":{"term":[{"id":"biologically-effective-dose","kind":"term","name":"Biologically effective dose (BED) and EQD2","route":"/terms/biologically-effective-dose/"},{"id":"brachytherapy-term","kind":"term","name":"Brachytherapy (internal radiotherapy)","route":"/terms/brachytherapy-term/"},{"id":"gray-unit","kind":"term","name":"Gray unit (Gy)","route":"/terms/gray-unit/"},{"id":"salvage-therapy","kind":"term","name":"Salvage therapy","route":"/terms/salvage-therapy/"},{"id":"sbrt-term","kind":"term","name":"Stereotactic body radiotherapy (SBRT / SABR)","route":"/terms/sbrt-term/"}],"cancer":[{"id":"idh-mutant-astrocytoma","kind":"cancer","name":"Astrocytoma, IDH-mutant (grades 2 to 4)","route":"/cancers/idh-mutant-astrocytoma/"},{"id":"cns-germ-cell-tumours","kind":"cancer","name":"Central nervous system germ cell tumours (germinoma and non-germinomatous)","route":"/cancers/cns-germ-cell-tumours/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"},{"id":"esthesioneuroblastoma","kind":"cancer","name":"Esthesioneuroblastoma (olfactory neuroblastoma)","route":"/cancers/esthesioneuroblastoma/"},{"id":"glioblastoma","kind":"cancer","name":"Glioma & glioblastoma","route":"/cancers/glioblastoma/"},{"id":"head-and-neck","kind":"cancer","name":"Head and neck squamous cell carcinoma","route":"/cancers/head-and-neck/"},{"id":"metastatic-anal-cancer","kind":"cancer","name":"Metastatic and recurrent anal squamous cell carcinoma","route":"/cancers/metastatic-anal-cancer/"},{"id":"nasopharyngeal","kind":"cancer","name":"Nasopharyngeal carcinoma","route":"/cancers/nasopharyngeal/"},{"id":"oligodendroglioma","kind":"cancer","name":"Oligodendroglioma, IDH-mutant and 1p/19q-codeleted","route":"/cancers/oligodendroglioma/"},{"id":"paediatric-high-grade-glioma","kind":"cancer","name":"Paediatric high-grade glioma (excluding diffuse midline glioma)","route":"/cancers/paediatric-high-grade-glioma/"},{"id":"recurrent-metastatic-nasopharyngeal-carcinoma","kind":"cancer","name":"Recurrent and metastatic nasopharyngeal carcinoma","route":"/cancers/recurrent-metastatic-nasopharyngeal-carcinoma/"}],"section":[{"id":"radiation","kind":"section","name":"Radiation Therapy","route":"/fronts/radiation/"}],"drug":[{"id":"dactinomycin","kind":"drug","name":"Dactinomycin (actinomycin D)","route":"/drugs/dactinomycin/"}]}}