Intraoperative radiation therapy: a critical analysis of the ELIOT and TARGIT trials. Part 2--TARGIT.

BACKGROUND: Two randomized intraoperative radiation therapy trials for early-stage breast cancer were recently published. The ELIOT Trial used electrons (IOERT), and the TARGIT-A Trial Update used 50-kV X-rays (IORT). These studies were compared for similarities and differences. The results were analyzed and used to determine which patients might be suitable for single-dose treatment. METHODS: The primary sources of data were the ELIOT Trial and TARGIT-A Trial, as well as a comprehensive analysis of the peer-reviewed literature of accelerated partial breast irradiation (APBI) using 50-kV X-rays or electrons. Studies published or presented prior to March 2014 were analyzed for efficacy, patient restrictions, complications, and outcome. RESULTS: With a median follow-up of 5.8 years, the 5-year recurrence rates for ELIOT versus EBRT patients were 4.4 and 0.4 %, respectively, p = 0.0001. A low-risk ELIOT group was identified with a 5-year recurrence rate of 1.5 %. With a median follow-up of 29 months, the 5-year recurrence rates for the TARGIT-A versus EBRT patients were 3.3 and 1.3 %, respectively, p = 0.042. CONCLUSIONS: With 5.8 years of median follow-up, IOERT appears to have a subset of low risk women for whom IOERT is acceptable. With 29 months of median follow-up the results of IORT with 50-kV devices are promising, but longer follow-up data are required. At the current time, single-fraction IOERT or IORT patients should be treated under strict institutional protocols.

Intraoperative radiation therapy: a critical analysis of the ELIOT and TARGIT trials. Part 1--ELIOT.

INTRODUCTION: Two randomized intraoperative radiation therapy trials for early-stage breast cancer were recently published. The ELIOT Trial used electrons (IOERT), and the TARGIT-A Trial Update used 50-kV X-rays (IORT). These studies were compared for similarities and differences. The results were analyzed and used to determine which patients might be suitable for single-dose treatment. METHOD: The primary sources of data were the ELIOT Trial and TARGIT-A Trial, as well as a comprehensive analysis of the peer-reviewed literature of accelerated partial breast irradiation (APBI) using 50-kV X-rays or electrons. Studies published or presented prior to March 2014 were analyzed for efficacy, patient restrictions, complications, and outcome. RESULTS: With a median follow-up of 5.8 years, the 5-year recurrence rates for ELIOT versus external beam radiation therapy (EBRT) patients were 4.4 % and 0.4 %, respectively, p = .0001. A low-risk ELIOT group was identified with a 5-year recurrence rate of 1.5 %. With a median follow-up of 29 months, the 5-year recurrence rates for the TARGIT-A versus EBRT patients were 3.3 % and 1.3 %, respectively, p = .042. CONCLUSION: With 5.8 years of median follow-up, IOERT appears to have a subset of low-risk women for whom IOERT is acceptable. With 29 months of median follow-up the results of IORT with 50-kV devices are promising, but longer follow-up data are required. At the current time, single-fraction IOERT or IORT patients should be treated under strict institutional protocols.

Intraoperative Electron Radiotherapy (IOERT) as an Alternative to Standard Whole Breast Irradiation: Only for Low-Risk Subgroups?

BACKGROUND: Intraoperative radiotherapy during breast-conserving surgery is being studied as an alternative to 6 weeks of external beam radiotherapy (EBRT) for low-risk women; it can be delivered using electrons (intraoperative electron radiotherapy, IOERT) or 50-kV X-rays. MATERIALS AND METHODS: We analyzed both single institutional and randomized studies involving single-fraction IOERT treatments. Rates for ipsilateral breast tumor recurrences, disease-specific survival, and overall survival were obtained. RESULTS: IOERT had true 5-year recurrence rates of > 1.5% for ASTRO (American Society for Radiation Oncology) and ESTRO (European Society for Therapeutic Radiology and Oncology) suitable women, or for low-risk women as defined by the ELIOT trial. Women with ductal carcinoma in situ eligible for breast-conserving therapy, older women that currently receive no EBRT, and younger women with favorable biology are additional potential candidates. CONCLUSION: ASTRO suitable and ESTRO good women for accelerated partial breast irradiation are low-risk groups. Higher-risk women with favorable biology might also be suitable candidates for IOERT, providing the tumor biology can be determined prior to surgery. For intraoperative radiotherapy using 50-kV X-rays, follow-up was too short to assess the effectiveness of the treatment.

Potential of mobile intraoperative radiotherapy technology.

Mobile IORT units have the potential to change the way patients who have cancer are treated. The integration of IORT into cancer treatment programs, made possible by the new technologies of mobile linear accelerators that can be used in unshielded operating rooms, makes IORT significantly less time-consuming, less costly, and less risky to administer. It is now practical for IORT to be used in early-stage disease, in addition to advanced disease, and in sites for which patient transportation in the middle of surgery is considered too risky. Preliminary results of trials for early-stage breast and rectal cancer indicate benefits of IORT. Pediatric patients and patients who have lung cancer, previously underserved by IORT therapies, can be offered potential gains when patient transport issues do not limit IORT. Furthermore, because many of these mobile systems require no shielding, it is now practical for mobile units to be shared between hospitals, making this new mobile technology much more widely available.