Radiotherapy with the MammoSite device

This study evaluated the efficacy and safety of accelerated partial breast irradiation (APBI) using the MammoSite device for the treatment of patients after breast conserving surgery.

After breast conserving surgery (BCS; surgical removal of the tumor and surrounding tissue without removal of the entire breast), radiotherapy is often used to kill any cancer cells that might have been left within the conserved breast, and to reduce the chance of recurrence (return of the cancer). APBI is a localized form of radiation therapy that delivers focused radiation only to the part of the breast from which the tumor was removed, while sparing the surrounding healthy tissue. Several different devices can be used to employ APBI.

The MammoSite device includes a small balloon that is inserted into the breast cavity left after removal of the tumor. A small seed of radioactive matter is inserted into the balloon by a catheter during treatments. APBI is administered in this manner over a period of 5 days. The MammoSite device has been approved for use since 2002, however, final analysis of the long term effects of treatment using this device have only recently been published.

This study involved a total of 1,449 patients treated with APBI using the MammoSite device.

5 years following treatment, only 2.8% of the patients treated with BCS and MammoSite APBI experienced cancer recurrence in the treated breast. 9.6% of patients were reported to suffer from breast infections due to treatment. However, 91.3% of patients were reported to achieve excellent cosmesis (achieved aesthetically pleasing results after breast reconstruction). These results were sustained even 7 years after treatment, at which point 90.6% of patients reported excellent cosmesis. Cancer specific survival after 6 years was 98.2%, and overall survival was 90.4% (the difference between the two is due to mortality from causes other than cancer).

This study concluded that APBI treatments using the MammoSite device show long term efficiency and safety.

This study did not compare the efficiency of MammoSite treatments with alternative methods of APBI or radiotherapy. In addition, one of the authors of this study is a consultant for Hologic, which developed and manufactures MammoSite.

Consult with your physician regarding the risks and benefits of the different radiotherapy methods available in the treatment of localized breast cancer.