Among the key findings:

· The recurrence rate for the 184 total IORT patients was 5.4 percent at a mean follow-up of 55 months; however, the recurrence rate was significantly lower – 2 percent – for the patients who complied with adjuvant medical therapy. The difference in recurrence rates between the group complying with versus declining adjuvant medical therapy was statistically significant.
· Adjuvant medical therapy was recommended to patients by their medical oncologists as a standard of care. Treatment included either chemotherapy and/or endocrine therapy as dictated by molecular subtype and, if appropriate, the 21-gene recurrence score.

· These results are similar to the TARGIT-A study, which compared risk-adapted radiotherapy using single-dose targeted intraoperative radiotherapy (TARGIT) to fractionated external beam radiotherapy (EBRT) for breast cancer. When TARGIT was administered at the time of lumpectomy, the trial showed the 5-year local recurrence rates were 2.1% for TARGIT vs. 1.1% for EBRT. The study concluded that IORT is non-inferior to EBRT.

"IORT continues to hold tremendous promise in the treatment of early-stage breast cancer. As our study shows, using IORT with the Xoft System, combined with other post-operative therapy, proved extremely effective in addressing early-stage breast cancer and preventing recurrences," said Barbara S. Schwartzberg, MD, FACS, lead author of the study and breast surgeon at Rose Medical Center. "Furthermore, we saw the Oncotype DX 21-gene recurrence score is useful in its predictive benefit when applied to IORT patients with invasive cancer. We believe that our results make a strong case for ASTRO suitability criteria for APBI to be amended to reflect patients' eligibility for IORT treatment, since they were not initially designed to provide guidelines for patients considering IORT."

IORT with the Xoft System uses a miniaturized X-ray source to deliver one precise, concentrated dose of radiation to a tumor site at the time of breast-conserving surgery (lumpectomy). The treatment can be completed in as little as eight minutes, making it possible for appropriately selected patients to replace six to eight weeks of post-operative EBRT with a single treatment. The Xoft System is cleared by the U.S. Food and Drug Administration, CE marked, and licensed in a growing number of countries for the treatment of cancer anywhere in the body, including early-stage breast cancer, non-melanoma skin cancer, and gynecological cancers. It has been used to successfully treat more than 15,000 patients worldwide.

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