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Intraoperative Radiation Therapy (IORT) to the Breast

This information will help you prepare for your intraoperative radiation therapy (IORT) to the breast at Memorial Sloan Kettering Cancer Center (MSKCC).

Radiation therapy can be used to reduce the return of a tumor to the breasts. There are different ways to give radiation to the breast. If a tumor is larger than 2 centimeters or there is more then 1 tumor, radiation is given to the whole breast. If the tumor is less than 2 centimeters, radiation can be given to the tissue that is near the tumor.

The Day of Your Procedure

Where to go

Please arrive at the Presurgical Center (PSC) at 1275 York Avenue between East 67th and East 68th Streets. This is the main building of MSKCC. Take the B elevator to the 6th floor.

What to expect

Once you arrive at the hospital, doctors, nurses, and other staff members will ask you to state and spell your name and date of birth many times. This is for your safety. Patients with the same or similar names may be having procedures on the same day.

After changing into a hospital gown, you will meet your nurse. He or she will place an intravenous (IV) catheter into a vein, usually in your hand or arm. At first you will receive fluids through the IV, but it will be used later to give you anesthesia (medication to make you sleepy). Your doctor will explain the procedure and answer any questions you have.

During Your Procedure

When it's time for your procedure, you will be brought into the operating room. You will be attached to equipment to monitor your heart, breathing, and blood pressure. You will also receive oxygen through your nose. You will receive anesthesia through your IV, which will make you fall asleep. Once you are asleep, your doctor will remove your tumor through an incision (surgical cut) that is made across your chest. Your doctor will also check the tissue near the tumor to make sure there are no other lumps.

After the tumor is removed, a radiation oncologist will place an applicator into your surgical cut. The applicator has thin catheters (small, flexible tubes) that are connected to a machine that holds radiation.

Once the applicators are positioned correctly, the operating staff will leave the room, close the door, and begin your treatment. It will take 30 to 40 minutes for you to receive the full dose of radiation. Although you are alone during your treatment, the operating staff can see you on a monitor and hear you through an intercom at all times.

When your treatment is done, the operating staff will return to the room. Your surgeon will remove the applicator and close your incision.

After Your Procedure

You may have a small drain in your breast that allows fluid to exit. You may be given antibiotics during the surgery to help prevent infection. You may also need to take them after you go home.

You will have follow-up appointments with your surgeon and radiation oncologist. Call each office to schedule an appointments

Side Effects

Some patients develop side effects from treatment. The type and how severe they are depend on many factors. These include the dose of radiation and your overall health.

Your skin in the treated area will become:

  • Red
  • Dark
  • Dry
  • Irritated (similar to a sunburn)

The redness and irritation will get better after your treatment is done. Your skin in the treated areas will always be drier than usual. A nurse will teach you how to care for your skin.

Permanent side effects from IORT are not common; however, you may notice a change in your treated breast. Your breast may feel hard and may change in appearance. This may happen 6 months or more after your treatment has been completed.


Most of the time, if your cancer does come back, it comes back near the site of the first cancer. This is the tissue that will be treated with IORT. Only the tissue surrounding the breast tumor is treated with IORT. You could get another cancer in another part of the same breast. This is less likely if the entire breast is treated, as is done with standard radiation therapy.