National Trends for Intra-operative Radiation Therapy in Favorable, Early-stage Breast Cancer: A Propensity Scoring Analysis of the National Cancer Database
Abstract
Background/Objective: Adjuvant whole breast irradiation (WBI) is recommended after breastconserving surgery for most patients with early-stage breast cancer. Recently, partial breast intraoperative radiotherapy (TARGIT-IORT), supported by randomised evidence, has emerged as a potential alternative treatment modality for suitable patients. IORT involves a single treatment at the time of lumpectomy, which is more convenient for the patient compared with 3-5 weeks of daily fractionated external beam WBI. We examined national trends regarding the use of IORT for breast cancer. Methods: We retrospectively reviewed the National Cancer Database (NCDB) and identified patients with clinical Stage I-III breast cancer who received breast-conserving surgery with either adjuvant WBI or IORT without adjuvant WBI between 2004-2014. Patient demographics, tumor characteristics, and survival were compared between the 2 groups. Univariate, multivariate, and stage-stratified propensity score weighted analyses were performed to compare study groups and survival. Results: We identified 2,871 (0.42%) eligible patients treated with TARGIT-IORT delivered at the time of the initial lumpectomy (“immediate”) and 675,429 (99.58%) patients treated with WBI. We excluded 141 patients treated with IORT during a procedure after the initial lumpectomy (“delayed”). Median follow-up was 54 months. The use of IORT significantly increased 16-fold in the 10 years from 0.07% in 2004 to 1.09% in 2014 (p