Application of 21-gene recurrence score results and ASTRO suitability criteria in breast cancer patients treated with intraoperative radiation therapy (IORT)

Background: American Society for Radiation Oncology (ASTRO) suitability criteria for accelerated partial breast irradiation (APBI) and the 21-gene recurrence score (RS) were evaluated for prognostic and predictive benefit in IORT patients. Methods: Outcomes of 184 patients completing IRB approved IORT protocol were retrospectively reviewed. Data included demographics, histopathology, RS, adjuvant therapy, locoregional (LRR) and distant recurrences (DR), and breast cancer-specific survival. Results: There were 10 (5.4%) breast cancer recurrences, including one breast cancer-specific death. All 184 patients were classified by ASTRO suitability criteria (suitable: 64% (5 LRR), cautionary: 30% (3 LRR), unsuitable: 6.0% (1 LRR, 1 DR leading to death). RS were available in 114 estrogen receptor positive patients (<11: 22% (1 LRR), 11-25: 63% (1 LRR), 26-30: 9%, > 30: 6%). Mean follow-up was 55 months. Conclusions: ASTRO suitability criteria for APBI and RS were useful in making prognostic and therapeutic recommendations for patients considering IORT. (c) 2018 Elsevier Inc. All rights reserved.