Single-institution Comparison of Accelerated Partial Breast Irradiation and Whole Breast Irradiation in Breast Cancer Patients with Unfavorable Parameters by the American Society for Radiation Oncology Guidelines

Abstract

AIM: The American Society for Radiation Oncology (ASTRO) issued guidelines regarding patients that were suitable for accelerated partial breast irradiation (APBI) following breast-conserving surgery (BCS) as an alternative to whole breast irradiation (WBI). However, the suitability criteria may not be based on updated data concerning the risk of ipsilateral breast tumor recurrence (IBTR) with APBI. We reviewed the experience of APBI and WBI in patients that would be characterized in the unfavorable categories based on the ASTRO guidelines. METHODS: Patients in both APBI and WBI cohorts were categorized into one of the three groups based on the ASTRO guidelines on ABPI: suitable, cautionary, or unsuitable. Consecutive patients who underwent BCS followed by APBI or WBI were examined to compare and determine patterns of treatment failures. RESULTS: Since November 2007, 203 patients receiving APBI and 132 receiving WBI were analyzed. Mean follow-up was longer than 3 years. In the APBI cohort (17 suitable, 87 cautionary, and 99 unsuitable patients), IBTR or regional recurrence was observed in 1 (5.9%), 1 (1.1%), and 3 (3.0%) patient, respectively. In the WBI cohort (14 suitable, 30 cautionary, and 88 unsuitable patients), IBTR or regional recurrence was observed in 0 (0%), 1 (3.3%), and 4 (4.5%) patients, respectively. When APBI patients were stratified according to the ASTRO category, there was no statistically significant difference in the local control rates. CONCLUSIONS: The clinical efficacy of APBI was comparable with that of WBI for local control after BCS in patients considered cautionary or unsuitable for APBI following the ASTRO guidelines.