MammoSite® five-day targeted radiation therapy received clearance from the U.S. Food and Drug Administration in 2002.

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Since then, more than 50,000 women have been treated.

MammoSite® therapy works from the inside, meaning that a higher daily dose can be used for a shorter period of time – five days vs. up to seven weeks.

It provides a treatment option that is of shorter duration, and that employs technology which minimizes damage to healthy cells and tissues. The design of the MammoSite® device gives radiation oncologists the ability to shape the radiation dose and to treat patients who would otherwise not be appropriate candidates for brachytherapy (radiation delivered through an implant).

Targeted vs. Conventional Radiation Therapy

With conventional radiation therapy, beams of radiation are delivered from outside the breast. These beams pass through the skin and internal tissues to treat the entire breast. Treatment generally involves daily doses of radiation for a period of 6 to 7 weeks.

With MammoSite® therapy, radiation is delivered from inside the breast and lumpectomy cavity. Radiation is therefore applied directly to the area where cancer is most likely to recur, which has several advantages.

  • Radiation exposure and the resulting effects are limited to a small internal area. This minimizes the skin discoloration, burning, and scarring often associated with conventional radiation therapy. With MammoSite®, there's generally little change in appearance and less fatigue.
  • Higher daily doses can be delivered over a shorter period of time – two doses a day for five days. This allows women to resume their normal lives and activities more quickly.

In addition, studies have shown both survival rate and recurrence rate with targeted therapy are comparable to conventional therapy.

How MammoSite Therapy Works


  • After a lumpectomy is performed to remove the breast-cancer tumor, a small, soft MammoSite® balloon attached to a thin tube (catheter) is placed inside the lumpectomy cavity through a small incision in the breast.
  • The balloon is “inflated” with saline solution so that it fits snugly into the cavity. It remains inflated throughout the five days of treatment.
  • A small portion of the catheter remains outside the breast; it is secured to a cushioned gauze pad to prevent movement of the catheter.


Treatment is planned by a radiation oncologist, who takes images of the MammoSite® balloon catheter in the breast and determines the amount of radiation needed.

During therapy, the portion of the catheter that remains outside the breast is connected to a computer-controlled machine that inserts a radiation “seed.” The seed delivers the specified dose of radiation.

  • Once therapy is complete, the seed is removed, the catheter is unplugged, and normal daily activity can resume.
  • No radiation source remains inside the breast between treatments.


  • After five days of treatment, your MammoSite® balloon catheter is removed –usually on the final day of treatment.
  • The balloon is gently removed through the same incision made to place it.

“Could I be a candidate for MammoSite® targeted radiation therapy?”

The breast surgeons and radiation oncologists at Medical City Plano are the best ones to answer that question. Many women with early-stage breast cancer are candidates for MammoSite® therapy. However, a number of different factors need to be taken into account. Your medical team will determine, based on various test results and reports, whether MammoSite® therapy is an option in your particular case.

“How can I find out more about the procedure?”

The breast physicians at Medical City Plano are your best source of information about any procedure or therapy that may apply to your particular situation.

“If I am judged to be a qualified candidate for MammoSite® therapy, is it possible that the treatment will not be administered?”

For a variety of reasons, even qualified candidates may not complete the five-day treatment. Talk to one of our physicians about all the risks and benefits of the treatment.