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.

How is intraoperative radiation therapy used to treat breast cancer?

In treating breast cancer, IORT is used in patients who have had a lumpectomy (removal of a tumor from the breast), rather than a mastectomy (removal of the entire breast). The IORT device delivers low-energy, high-dose radiation directly to the tumor bed (the cavity left after the tumor has been removed from the breast) in the operating room, right after the tumor has been removed.

After the lumpectomy, a spherical applicator on the IORT device is placed directly into the tumor bed and delivers a smaller dose of x-rays than is delivered in standard radiation therapy. The IORT treatment usually takes about 30 minutes.

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.

What are the advantages of intraoperative radiation therapy?

IORT has the following advantages:

  • All of the needed radiation can be delivered at one time. The “standard” radiation therapy schedule for breast cancer is five days a week for up to six weeks. IORT saves time, and is more convenient for the patient.
  • The radiation dose in IORT is much smaller than that of external beam radiotherapy.
  • Nearby normal organs and tissues receive less radiation from the IORT radiation.
  • If necessary, the patient can have another lumpectomy if another tumor is found in the breast in the future.
  • IORT costs significantly less than external beam radiotherapy.

What are the side effects of intraoperative radiation therapy?

The main side effects of IORT are bruising and excess fluid buildup in the breast tissues.


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This document was last reviewed on: 10/10/2013...#15307

© Copyright 1995-2013 The Cleveland Clinic Foundation. All rights reserved.