Accelerated partial breast irradiation via brachytherapy: a patterns-of-care analysis with ASTRO consensus statement groupings

Abstract

Purpose: The 2002 Food and Drug Administration approval of the MammoSite catheter (Hologic, Inc., Beford, MA) led to a surge of interest in accelerated partial breast irradiation (APBI). Until recently, guidelines as to the optimal candidates for this treatment were unavailable. We performed a patterns-of-care analysis for patients undergoing breast brachytherapy and compared these results with the American Society for Radiation Oncology (ASTRO) consensus statement.

Methods and materials: The Surveillance, Epidemiology, and End Results database was used to examine female breast cancer patients treated with brachytherapy between 2002 and 2007. The patients were then categorized into suitable, cautionary, and unsuitable groups based on the ASTRO guidelines.

Results: We identified 4172 female breast cancer patients treated within the stated years. The number of brachytherapy cases increased nearly 10-fold over the time period studied from 163 in 2002 to 1427 in 2007 (p<0.0001). Patients with data missing were excluded, leaving a total of 3593 patients available for analysis. The mean patient age was 64 years. Most patients had small (<2cm in 80.9%) estrogen receptor-positive (86.7%) invasive (88.6%) tumors. The percentage of patients treated for ductal carcinoma in situ increased with time (p<0.001), whereas the percentage of patients treated with positive lymph nodes decreased with time (p<0.001). Using the data available, 1369 (38.1%), 1563 (43.5%), and 661 (18.3%) patients were characterized as suitable, cautionary, and unsuitable, respectively.

Conclusions: More than 60% of patients who received APBI via brachytherapy would fall into the ASTRO cautionary or unsuitable groupings. This is the largest patterns-of-care analysis for APBI patients and serves as a baseline for future comparison.