Intraoperative electron radiotherapy in early-stage breast cancer: A report on 226 patients.

143 Background: We report the results of a single-institution phase II trial of accelerated partial breast irradiation (APBI) using a single dose of intraoperative electron radiotherapy (IOERT) in patients with low-risk early-stage breast cancer. Methods: From July 2006 to December 2009, 226 patients suitable for BCT were enrolled in a phase II trial with IOERT as radical treatment immediately after surgical resection. All patients had biopsy-proven cancer. After the surgeon temporarily re-approximated the excision cavity, a dose of 21 Gy using IOERT was delivered to the tumor bed with a margin of 2 cm laterally. Results: No acute reactions were reported after irradiation. Three patients experienced a transient edema. In 7 others a haematoma was observed. No cases of liponecrosis were observed. With a mean follow-up of 49 months (range 31-66 months), only one case of local recurrence has been reported. The observed toxicity was considered acceptable. As to cosmetic results, at 6 months after the end of IO...