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Independent study confirms efficacious breast cancer treatment
NASHUA, N.H.—iCAD has just announced the results of a long-term independent study conducted with the Xoft Axxent Electronic Brachytherapy (eBx) System for the treatment of early-stage breast cancer using intraoperative radiation therapy (IORT).
With a mean follow-up of 55 months, outcomes published in The American Journal of Surgery showed that breast cancer recurrence rates of patients who were treated with IORT using the Xoft System and complied with adjuvant medical therapy were comparable to those seen in the cornerstone TARGIT-A study, which evaluated IORT using different technology. To date, this study presents the most long-term research of IORT using the Xoft System published in a peer-reviewed journal.
The retrospective study, “Application of 21-gene recurrence score results and ASTRO suitability criteria in breast cancer patients treated with intraoperative radiation therapy (IORT),” evaluated the American Society for Radiation Oncology (ASTRO) suitability criteria for APBI and the 21-gene recurrence score for prognostic and predictive benefit in IORT patients over a nearly five-year period. The research was led by Barbara Schwartzberg, MD, FACS, conducted at the Rose Medical Center in Denver, Colorado, and was not company sponsored.
“As the growing body of clinical evidence supporting the use of the Xoft System for IORT continues to mature and expand, we are thrilled to see members of our global base of clinical users publishing landmark results that validate the long-term effectiveness of our unique technology,” said Ken Ferry, CEO of iCAD. “The compelling findings, comparable to other IORT methods previously examined, show IORT with the Xoft System is successful in delivering positive outcomes for patients with early-stage breast cancer that comply with their full course of treatment.”
The study reviewed results of 184 patients with breast cancer from November 2011 to January 2016 completing Institutional Review Board (IRB)-approved IORT protocol. Data included demographics, histopathology, the 21-gene recurrence score, adjuvant therapy, locoregional and distant recurrences, and breast cancer-specific survival. All patients were classified by ASTRO suitability criteria (suitable: 64 percent, cautionary: 30 percent, unsuitable: 6 percent), with a mean follow-up of 55 months.
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 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.
“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 Schwartzberg, who is 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.”