What is intraoperative radiation therapy?

Intraoperative radiation therapy (IORT) is a treatment for cancer in which the radiation is delivered directly to a small area of the body, all at once. This is different from the usual method of delivering radiation, in which a larger part of the body (such as an entire organ) receives radiation for a longer period of time.

Studies of intraoperative radiation therapy

The major study of IORT in breast cancer was the TARGIT-A trial. In this study, breast cancer patients were given either IORT or standard radiation therapy (known as external beam radiotherapy, or EBRT).

The study was designed to determine how often the breast cancer recurred (returned). The results showed that after four years, both therapies were almost equally effective: six patients in the IORT group, and five in the EBRT group, had recurrences of breast cancer.

In another, more recent study, 78 patients were treated with IORT; none of the patients had a breast cancer recurrence.

Which breast cancer patients should receive intraoperative radiation therapy?

Patients who may most benefit from IORT for breast cancer are over the age of 50 and have early stage breast cancer that has not spread.

Last reviewed by a Cleveland Clinic medical professional on 10/10/2013.


  • Vaidya JS, Joseph DJ, Tobias JS, et al. Targeted intraoperative radiotherapy versus whole breast radiotherapy for breast cancer (TARGIT-A trial): an international, prospective, randomised, non-inferiority phase 3 trial. Lancet 2010 Jul 10;376(9735):91-102. Accessed 10/11/2013.
  • Grobmyer SR, Lightsey JL, Bryant CM, et al. Low-kilovoltage, single-dose intraoperative radiation therapy for breast cancer: results and impact on a multidisciplinary breast cancer program. J Am Coll Surg 2013 Apr;216(4):617-23. Accessed 10/11/2013.

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