# Intraoperative radiotherapy (IORT)

Source: https://onco.cc/technologies/intraoperative-radiotherapy/  
OnCo record `intraoperative-radiotherapy` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Giving a single large dose of radiation directly to the tumour bed during surgery, with normal organs moved out of the way; used mainly in breast cancer as an alternative to weeks of external radiotherapy.

## Summary

IORT delivers 10-21 Gy in one fraction via electrons (mobile linacs, ELIOT), low-energy X-rays (Intrabeam, TARGIT) or HDR brachytherapy applicators. In early breast cancer, TARGIT-A (BMJ 2020, long-term) showed risk-adapted IORT non-inferior for local recurrence with fewer non-breast-cancer deaths, while ELIOT (Lancet Oncol 2021) showed higher local recurrence with electron IORT than whole-breast RT (though survival was equal); ASTRO regards it as suitable for selected low-risk patients within trials or registries. Other uses: locally advanced rectal cancer and retroperitoneal sarcoma (margin boost), pancreatic cancer, paediatric tumours. Competing partial-breast approaches (5-fraction external APBI, brachytherapy) and FLASH radiotherapy overlap.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-09-08
- Tags: gap-fill
- Principle: Direct visualisation and displacement of organs at risk allow a large single fraction to the highest-risk tissue with steep dose fall-off, exploiting the radiobiology of high dose per fraction.
- Since: 1965
- Strengths: Single session; completes radiotherapy during surgery; Sparing of skin, heart and lung; Useful boost for close margins in sarcoma and rectal cancer
- Limitations: Higher local recurrence than whole-breast RT in ELIOT; Final pathology unknown at time of treatment; Equipment and workflow costs

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Intraoperative_radiation_therapy
- TARGIT-A long-term (BMJ 2020): https://doi.org/10.1136/bmj.m2836
- ELIOT long-term (Lancet Oncol 2021): https://doi.org/10.1016/S1470-2045(21)00080-2

## Connected records

- technologies: [Brachytherapy](https://onco.cc/technologies/brachytherapy/), [Electron beam therapy systems (linac electrons, total skin electron units, mobile electron IORT)](https://onco.cc/technologies/electron-beam-therapy-systems/), [FLASH radiotherapy](https://onco.cc/technologies/flash-rt/), [IMRT / IGRT (modern external beam)](https://onco.cc/technologies/imrt-igrt/), [Remote afterloaders for HDR brachytherapy](https://onco.cc/technologies/brachytherapy-afterloaders/)
- cancers: [Breast cancer (all types)](https://onco.cc/cancers/breast-cancer/), [Colorectal cancer](https://onco.cc/cancers/colorectal/), [HR-positive / HER2-negative breast cancer](https://onco.cc/cancers/breast-hr-positive/), [Pancreatic ductal adenocarcinoma](https://onco.cc/cancers/pancreatic/), [Sarcomas (soft tissue, bone, GIST)](https://onco.cc/cancers/sarcoma/)
- fronts: [Radiation Therapy](https://onco.cc/fronts/radiation/), [Surgery & Interventional](https://onco.cc/fronts/surgery/)
- companies: [Carl Zeiss Meditec](https://onco.cc/companies/carl-zeiss-meditec/), [IntraOp Medical](https://onco.cc/companies/intraop-medical/)
- terms: [Partial-breast irradiation](https://onco.cc/terms/partial-breast-irradiation/)
- trials: [Breast Cancer With Intraoperative Radiotherapy Followed by Hypofractionated External Beam Radiotherapy](https://onco.cc/trials/nct05498311/), [Intraoperative Radiotherapy for Korean Patients With Breast Cancer](https://onco.cc/trials/nct02213991/), [Intraoperative Radiotherapy in Newly Diagnosed Glioblastoma Multiforme](https://onco.cc/trials/nct02685605/), [TARGIT-A (targeted intraoperative radiotherapy)](https://onco.cc/trials/targit-a/)
- key papers: [Intraoperative irradiation for early breast cancer (ELIOT): long-term recurrence and survival outcomes from a single-centre, randomised, phase 3 equivalence trial](https://onco.cc/key-papers/paper-orecchia-lancet-oncol/), [Long term survival and local control outcomes from single dose targeted intraoperative radiotherapy during lumpectomy (TARGIT-IORT) for early breast cancer: TARGIT-A randomised clinical trial](https://onco.cc/key-papers/paper-vaidya-bmj/)
- institutions: [Fundación Arturo López Pérez](https://onco.cc/institutions/falp-chile/), [Tianjin Medical University Cancer Institute and Hospital](https://onco.cc/institutions/tmucih/)
- roadmaps: [Radiotherapy roadmap: X-rays → shaped beams → fewer fractions, particles and FLASH](https://onco.cc/roadmaps/radiation-roadmap/), [Surgery roadmap: radical operations → less surgery → no surgery when a drug has done the work](https://onco.cc/roadmaps/surgery-roadmap/)

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