The TARGIT trial: targeted intraoperative radiation therapy versus conventional postoperative whole-breast radiotherapy after breast-conserving surgery for the management of early-stage invasive breast cancer (a trial update)

Background The principal objective of the targeted intraoperative radiation therapy trial was to determine whether single-fraction intraoperative radiotherapy (IORT) targeted to the tumor bed provides equivalent local control compared with whole-breast irradiation in patients with early-stage invasive breast cancer. Methods Patients were randomized equally to IORT versus whole breast irradiation. Patients randomized to IORT received tumor bed irradiation prescribed at 20 Gy to the surgical margins using soft x-rays (50 kV) delivered with the Intrabeam Photon Radiosurgery System (Zeiss Inc, Oberkochen, Germany). Patients randomized to whole-breast irradiation received radiotherapy postoperatively. Prior wide local excision was allowed. Patients randomized to IORT after initial breast-conserving surgery received IORT at a second operation. Results A total of 779 patients were accrued at 16 institutions internationally. Five hundred sixty patients were randomized before initial breast-conserving surgery. One hundred eighty-three patients were randomized after initial breast-conserving surgery. The median follow-up time was 359 days. Conclusion Targeted IORT allowed the entire dose of radiotherapy to be administered in a single fraction at the time of breast-conserving surgery, thus avoiding the need for repeated radiotherapy treatments or placement of indwelling radiotherapy devices.