Background: Data on recent trends and correlates of utilization for accelerated partial breast irradiation using brachytherapy (APBI-b) for ductal carcinoma in situ (DCIS) are lacking.
Methods: This study included 113,841 DCIS patients from the National Cancer Data Base, of whom 8,709 (6.5 %) underwent APBI-b and 105,132 (93.5 %) underwent external beam irradiation after lumpectomy between 2003 and 2011. Trends in APBI-b use, American Society for Radiation Oncology (ASTRO) guideline concordance, and independent factors related to APBI-b use were examined.
Results: APBI-b use increased from 1.6 % in 2003 to 11.9 % in 2008 and then decreased to 9.1 % in 2011 (p < 0.001). Before 2009, 24.6 % of patients undergoing APBI-b were in the ASTRO guideline 'unsuitable' category, but this proportion decreased to 14.6 % after 2009 (p < 0.001). When adjusting for year of diagnosis, patient, tumor, and facility factors, the four strongest independent factors for APBI-b use were year of diagnosis followed by facility location, facility volume, and facility type. APBI-b use was highest in the East South Central census region (13.1 %) and lowest in the New England region (2.0 %). A statistically significant interaction was identified between facility type and volume. Patients in community cancer programs of large volume were more likely to receive APBI-b, whereas patients in larger academic programs were less likely to receive APBI-b.
Conclusion: APBI-b for DCIS decreased from 2008 to 2011. After year of diagnosis, facility factors were most strongly associated with APBI-b use as opposed to patient and tumor factors. Reasons for these trends are multifactorial and deserve further study.