Accelerated partial-breast irradiation versus whole-breast irradiation for early-stage breast cancer patients undergoing breast conservation, 2003-2010: a report from the national cancer data base.

BACKGROUND: Previous studies have demonstrated an increase in the utilization of accelerated partial-breast irradiation via brachytherapy (APBI-b), but larger, more contemporary studies examining overall APBI use are lacking.
METHODS: A total of 575,438 nonneoadjuvant American Joint Committee on Cancer stage 0 to II breast conservation patients were selected from the National Cancer Data Base from 2003 to 2010 who underwent either whole-breast irradiation or APBI.
RESULTS: Overall, 59,396 patients (10.3 %) underwent APBI. The use of APBI for the entire cohort increased from 3.4 % in 2003 to 12.8 % (p < 0.001) in 2008 and then decreased to 12.4 % in 2010. Three-dimensional conformal radiation increased from 0.8 to 2.2 %, intensity-modulated radiotherapy increased from 0.7 to 1.3 %, and brachytherapy (APBI-b) increased from 2.0 to 8.9 %. The most significant factors associated with APBI use were patient age and facility location. Patients 80-89 years old were 3.8 times more likely to undergo APBI compared to patients 30-39 years old (odds ratio [OR] 3.77, 95 % confidence interval [CI] 3.45-4.10, p < 0.001). Patients living in the West census region were 2.0 times more likely to undergo APBI compared to patients living in the Northeast (OR 2.0, 95 % CI 1.93-2.15, p < 0.001). Using the American Society of Radiation Oncology (ASTRO) guidelines, among patients with noninvasive cancer who received APBI, 95.6 % were categorized as "cautionary" and 4.4 % as "unsuitable." Of the invasive patients, 43.8 % were categorized as "suitable," 47.0 % as "cautionary," and 9.2 % as "unsuitable."
CONCLUSIONS: The utilization of APBI has stabilized at approximately 12 % starting in 2008. The majority of APBI is delivered using APBI-b, with patient age being the most significant factor associated with APBI use.