Purpose: Results from four major hypofractionated whole-breast radiotherapy (HF-WBRT) trials have demonstrated equivalence in select patients with early-stage breast cancer when compared with conventionally fractionated WBRT (CF-WBRT). Because relatively little data were available on patients receiving neoadjuvant or adjuvant chemotherapy, consensus guidelines published in 2011 did not endorse the use of HF-WBRT in this population. Our goal is to evaluate trends in utilization of HF-WBRT in patients receiving chemotherapy.
Methods and materials: We retrospectively analyzed data from 2004 to 2013 in the National Cancer DataBase on breast cancer patients treated with HF-WBRT who met the clinical criteria proposed by consensus guidelines (i.e., age >0 years, T1-2N0, and breast-conserving surgery), regardless of receipt of chemotherapy. We employed logistic regression to delineate and compare clinical and demographic factors associated with utilization of HF-WBRT and CF-WBRT.
Results: A total of 56,836 women were treated with chemotherapy and WBRT (without regional nodal irradiation) from 2004 to 2013; 9.0% (n = 5093) were treated with HF-WBRT. Utilization of HF-WBRT increased from 4.6% in 2004 to 18.2% in 2013 (odds ratio [OR] 1.21/year; P < 0.001). Among patients receiving chemotherapy, factors most dramatically associated with increased odds of receiving HF-WBRT on multivariate analysis were academic facilities (OR 2.07; P < 0.001), age >80 (OR 2.58; P < 0.001), west region (OR 1.91; P < 0.001), and distance >50 miles from cancer reporting facility (OR 1.43; P < 0.001). Factors associated with decreased odds of receiving HF-WBRT included white race, income <$48,000, lack of private insurance, T2 versus T1, and higher grade (all P < 0.02).
Conclusions: Despite the absence of consensus guideline recommendations, the use of HF-WBRT in patients receiving chemotherapy has increased fourfold (absolute = 13.6%) over the last decade. Increased utilization of HF-WBRT should result in institutional reports verifying its safety and efficacy.
Keywords: Chemotherapy; Hypofractionation; National Cancer Database; Radiation therapy.