Research Compares Safety of Breast Cancer Radiation Techniques

WEDNESDAY, Nov. 8 (HealthDay News) -- A form of radiation treatment used to fight breast cancer may deliver higher doses of radiation to the heart than previously believed, new research shows.

In women being treated for left-sided breast cancers, MammoSite brachytherapy does not always expose the heart to lower doses of radiation than another delivery method, called intensity modulated radiation therapy (IMRT), concludes a study from Fox Chase Cancer Center in Philadelphia.

In MammoSite brachytherapy, a balloon is surgically placed at the site where the breast tumor was removed, and radiation is delivered into the balloon through a catheter. IMRT delivers precisely-targeted and controlled external beam radiation to the tumor site.

"In theory, MammoSite brachytherapy has generally been associated with lower doses to the heart for left-sided breast cancers, but in our study, we found that IMRT in some patients confers less radiation to the heart when treating areas close to the chest wall," Dr. Alice Tsai, a resident in the radiation oncology department at Fox Chase, said in a prepared statement.

In this study, the researchers simulated MammoSite brachytherapy in 101 women with left-sided breast tumors treated with IMRT. They analyzed data in an attempt to determine the minimum distance from the chest wall that the MammoSite balloon implant should be placed in order to reduce the amount of radiation received by the heart, but they could not determine a uniform distance.

"Care must be taken when assessing women who are candidates for MammoSite brachytherapy with thorough evaluation of CT scans to minimize heart toxicity when left breast tumors are close to the chest wall," Tsai said.

The study was expected to be presented Wednesday at the annual meeting of the American Society for Therapeutic Radiology and Oncology, in Philadelphia.