Ipsilateral breast tumor recurrence rates in breast cancer patients treated with preoperative chemotherapy, breast conserving surgery and intraoperative radiotherapy with electrons.

Abstract Abstract #5156 Introduction: Ipsilateral breast tumor recurrence (IBTR) rates are reported to be increased in patients treated with breast conserving surgery after preoperative chemotherapy. Aim of this study was to evaluate the IBTR rate in patients who were treated with preoperative chemotherapy followed by breast conserving surgery and intraoperative radiotherapy with electrons (IOERT). Patients and Methods: 84 patients with clinical stage II or III breast cancer were included in the study. Patients received 3 to 6 cycles of anthracyclin/taxane containing preoperative chemotherapy. All patients had breast conserving surgery with sentinel node biopsy and axillary lymph node dissection and received intraoperative radiotherapy with 9 Gy to the 90% reference isodose as an anticipated boost radiation. Whole breast radiotherapy (WBRT) was performed after surgery for all patients. Results: Pathologic complete response was achieved in 18/84 (21%) patients. Mean resection volume was 250 ml. After a median follow-up of 30.5 months (range 6 – 77 months) no IBTR could be observed. One patient developed a locoregional recurrence in the axilla and nine patients developed distant disease, five of those died of disease. Three patients developed contralateral breast cancer. 71 patients are alive without evidence of disease. Conclusion: Breast conserving surgery with IOERT in boost modality after preoperative chemotherapy is a reliable tool for the prevention of IBTR. The period between IOERT and WBRT is short as no adjuvant chemotherapy is necessary. Cosmetic outcome is excellent. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5156.