Outcome after ipsilateral breast tumor recurrence in patients with early-stage breast cancer treated with accelerated partial breast irradiation.

PURPOSE: Limited outcomes exist in patients who develop an ipsilateral breast tumor recurrence (IBTR) after accelerated partial breast irradiation (APBI). The purpose of this study was to evaluate these outcomes and patterns of failure in our cohort of patients undergoing APBI.

METHODS AND MATERIALS: A total of 534 patients with early-stage breast cancer were treated with APBI between 1993 and 2010. Clinical, pathologic, and treatment-related variables were analyzed. Clinical outcomes, including further IBTR, regional recurrence, disease-free survival, cause-specific survival, and overall survival were analyzed.

RESULTS: Eighteen (3.3%) patients developed an IBTR, for a 5-year actuarial rate of 2.0%; 14 (77.8%) of the recurrences were thought to represent new primary cancers. After IBTR, 13 (72.2%) patients were managed with salvage mastectomy and 4 (22.2%) patients with a second attempt at breast-conserving therapy. Five-year rates of disease-free survival, cause-specific survival, and overall survival after salvage mastectomy for IBTR were 81%, 100%, and 100%, respectively. In the 4 patients treated with a second attempt at breast-conserving therapy, no IBTR, axillary failure, regional recurrence, or distant metastases were noted at 5 years.

CONCLUSIONS: IBTRs that developed after APBI resulted in excellent clinical outcomes comparable with those observed after whole-breast irradiation.