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.