INTRAOPERATIVE RADIATION
THERAPY (IORT)
A complete guide to IORT โ radiation delivered directly to the tumour bed during surgery, under direct vision, with healthy organs physically protected. Used for breast, pancreatic, rectal, and other cancers where close-range precision during the operation offers advantages not achievable with post-operative external radiation.
analyticsAt a Glance
- check_circleIORT delivers radiation directly to the tumour bed during the operation โ the surgeon can see and protect adjacent healthy organs in real time.
- check_circleFor selected breast cancers, IORT may replace 3-6 weeks of post-operative whole-breast radiotherapy โ completing local treatment in a single session.
- check_circleTARGIT and ELIOT randomised trials established IORT as non-inferior to whole-breast radiotherapy for local recurrence in carefully selected early breast cancers.
- check_circleAvailable at specialist surgical oncology centres in China and India โ CancerFax helps identify appropriate centres for each indication.
What Is Intraoperative Radiation Therapy?
IORT is a way of giving radiation treatment in a single, concentrated dose directly to the area where a tumour has just been removed โ during the operation itself, while the patient is under anaesthesia and the surgical site is open. The radiation targets the tumour bed: the tissue most likely to contain microscopic cancer cells the surgeon cannot see.
โIORT treats the highest-risk tissue under direct surgical vision โ the radiation oncologist can see exactly where it needs to go, and the surgeon can physically move healthy organs out of the way.โ
Why Treat During Surgery?
During an operation, three advantages are available that are impossible with post-operative external radiation: direct visualisation of the tumour bed, ability to physically displace or shield sensitive structures, and immediate treatment before any microscopic cells have time to repopulate.
Electron Beam IORT (IOERT)
The most common IORT technique. A specialised electron beam applicator is placed directly on the tumour bed and a single high-dose fraction is delivered by a mobile LINAC. Used for breast, rectal, pelvic, gastric, and pancreatic tumours. Electrons deposit dose at the surface and stop โ protecting underlying structures.
Low-Energy X-Ray IORT (TARGIT / Intrabeam)
A spherical applicator delivering 50 kV X-rays is placed in the tumour cavity after lumpectomy. Used for the TARGIT-A breast cancer trial โ low-energy X-rays have a very steep dose fall-off, delivering high dose to the cavity surface and near-zero dose 1-2 cm beyond it.
HDR Brachytherapy IORT
A brachytherapy catheter or applicator is placed intraoperatively and loaded with a high-activity radioactive source using standard afterloading equipment. Used in some rectal and gynaecological cancer settings where the brachytherapy geometry provides dosimetric advantages over electron IORT.
Which Cancers Is IORT Used to Treat?
IORT is a specialised tool used in specific surgical settings. It is not a replacement for all radiotherapy โ its use requires careful patient selection by an experienced multidisciplinary team.
Breast Cancer โ The Strongest Evidence Base
TARGIT-A (low-energy X-ray IORT) and ELIOT (electron IORT) are both Phase III randomised trials comparing breast-conserving surgery with IORT versus surgery with whole-breast EBRT. Both demonstrated non-inferior local control in selected low-risk patients (older women, ER-positive, HER2-negative, node-negative, grade 1-2). IORT reduces 3-6 weeks of daily radiotherapy to a single intraoperative session.
Pancreatic Cancer โ Dose Escalation to a Protected Site
For locally advanced or borderline resectable pancreatic cancer, IORT is used to boost the dose to the tumour bed, particularly the retroperitoneal margin, after resection. The duodenum, small bowel, and other dose-limiting structures can be physically moved away during surgery. IORT allows dose delivery that would cause unacceptable toxicity if attempted with external beam.
Rectal and Pelvic Cancers โ Re-Irradiation and Close Margins
IORT is used for locally advanced rectal cancer with close or involved surgical margins, and for pelvic recurrences where prior radiation limits further external beam treatment. Direct application to the surgical surface allows high dose delivery when proximity to the ureters, bladder, or sacral nerves would make external beam hazardous.
Gastric, Soft Tissue Sarcoma, and Other Sites
IORT is used in selected gastric cancer cases as a boost at the anastomosis or nodal regions. For retroperitoneal soft tissue sarcomas, IORT allows high-dose delivery to the posterior margin where complete surgical resection is limited by the proximity of the spinal cord and major vessels.
Key Evidence Numbers
- TARGIT-APhase III RCT: IORT Non-Inferior to WBRT for Selected Breast CancerLocal recurrence rates: IORT 3.3% vs WBRT 1.3% at 5 years โ acceptable for low-risk patient selection criteria.
- ELIOTPhase III RCT: Electron IORT vs Whole-Breast EBRTHigher in-breast recurrence in unselected patients โ selection criteria are critical for ELIOT protocol.
- 1Treatment Session โ Breast IORT (vs 15-33 for EBRT)Single intraoperative session replaces 3-6 weeks of post-operative daily radiotherapy in eligible patients.
- 5-10%Global Use in Breast Cancer RadiotherapyIORT remains a minority approach โ appropriate patient selection is more important than technique alone.
IORT vs Post-Operative External Beam Radiotherapy: How to Decide
IORT is not right for all patients. Patient selection is the most critical determinant of outcomes.
IORT May Be Appropriate When
- Low-risk early breast cancer (TARGIT criteria)Age 45+, ER-positive, HER2-negative, node-negative, grade 1-2, clear margins โ select patients may be eligible for IORT alone.
- Pancreatic cancer with retroperitoneal margin concernWhere external beam boost would require unacceptable doses to duodenum and bowel.
- Recurrent pelvic cancer in previously irradiated fieldWhere external beam re-irradiation is not feasible due to prior dose.
- Patient with significant logistical barriers to extended radiotherapyDistance from treatment centre, inability to attend daily sessions for 3-6 weeks.
Standard Post-Op EBRT Preferred When
- Higher-risk breast cancer featuresLymph node involvement, HER2-positive, ER-negative, lobular histology โ whole-breast EBRT with boost remains standard.
- When post-operative pathology changes the treatment planIORT is delivered before pathology is available โ final histology may indicate need for EBRT regardless.
- When IORT infrastructure is not availableRequires specialist mobile LINAC, operative team training, and radiation physics support in or near the OR.
- Complex 3D target volumeNodal regions and extended post-operative fields requiring IMRT-based dose sculpting.
Related Guides in the Radiation Therapy Library
Explore related radiation therapy techniques.
Frequently Asked Questions
About IORT
Does IORT during breast surgery mean I need no further radiation afterwards?
For carefully selected patients who meet the eligibility criteria of the TARGIT-A or ELIOT trials (typically older women, low-risk tumour biology, clear margins), IORT can replace post-operative whole-breast radiotherapy. However, if final pathology reveals unexpected features โ such as close margins, lymphovascular invasion, or more extensive disease โ supplementary post-operative radiotherapy may still be recommended. This possibility should be discussed with the treatment team before surgery.
Is IORT available in India and China?
IORT infrastructure is available at selected specialist surgical oncology centres in both countries. It requires a mobile linear accelerator (for electron IORT) or a specialised low-energy device (for X-ray IORT) in or near the operating room, combined with radiation physics support. Larger cancer centres in both countries including those associated with CancerFax's partner network offer IORT. CancerFax can identify appropriate centres for specific indications.
What are the side effects of IORT?
For breast IORT, the most common side effect is fat necrosis at the treatment site โ firm, sometimes palpable tissue at the lumpectomy cavity. This occurs in 10-20% of patients and is usually asymptomatic. Radiation-related wound healing issues are uncommon. For abdominal and pelvic IORT, specific risks depend on the structures in the treatment field โ the surgical team will explain risks relevant to each patient's anatomy and the planned treatment.
How CancerFax Helps
CancerFax is a specialist cancer access and patient-navigation platform. We help patients and families understand their options, organise medical records, coordinate hospital communication, and support cross-border treatment planning where appropriate.
We help collect and organise reports, scans, pathology, biomarker results, and treatment history for structured case review.
We communicate with hospitals or trial teams to assess whether a case may be suitable for further screening.
We support appointment coordination, document submission, translation, and direct communication with international departments.
For international patients, we help with practical coordination โ travel planning, hospital admission guidance, and local support.
If this option is not suitable, we help explore other relevant treatments, clinical trials, or advanced care pathways.
From inquiry through to follow-up, our coordinators provide a single point of contact for the family.
CancerFax does not guarantee treatment access, eligibility, or clinical outcome. Our role is to help patients access accurate information, structured review, and appropriate specialist pathways.
Is IORT an Option for Your Cancer Surgery?
Upload your medical reports and surgical plan โ our radiation oncology team will review your case and advise on whether IORT is appropriate for your specific diagnosis and surgical approach.
This content is for informational purposes only and does not constitute medical advice. All treatment decisions must be made in consultation with a qualified surgical and radiation oncologist team.