Abstract P1-15-16: The utilization of hypofractionated breast radiotherapy in the United States between 2003 and 2011

Abstract

Abstract Background: Recently, several randomized trials have found that accelerated hypofractionated whole breast irradiation (HF-WBI) had equivalent local recurrence rates and disease-free survival, compared to conventional fractionated whole breast irradiation (CF-WBI). It is unknown if the pattern of care regarding HF-WBI has changed in the United States after the publication of these trials, given its administrative advantage. Methods: Using data from the National Cancer Database, this study included 559,362 non-metastasic female breast cancer patients who received post-lumpectomy external beam radiotherapy to their breast or regional nodes. We examined the trend of HF-WBI use in the U.S. and factors related to its use using logistic regression models. Results: Of patients receiving external beam radiotherapy, about 5% underwent HF-WBI. The most common HF-WBI dose schedule is 42.4-42.6 Gy in 16 fractions without or with boost radiation. There was a 20-fold increased trend in the use of HF-WBI, increasing from about 0.6% in 2003 to 13% in 2011 (p<0.0001). Among patients with pT1-2N0-1 disease, a subgroup for whom previous clinical trials of HF-WBI are mainly applicable, HF-WBI use increased from 0.6% in 2003 to 14% in 2011. Although not included in previous clinical trials, patients with ductal carcinoma in situ also experienced an increased use of HF-WBI, from 0.5% in 2003 to 12% in 2011. We found age was strongly correlated with HF-WBI use; the older a patient, the more likely she received HF-WBI. African Americans were less likely to use HF-WBI. Patients with low grade were more likely to receive HF-WBI than those with high grade and patients with negative nodes are more likely to received HF-WBI. Large volume, academic cancer centers are more likely to adopt HF-WBI than community cancer programs. Interestingly, patients who live at least 50 miles away from a cancer center are about 58% more likely to receive HF-WBI than patients living within 50 miles of a cancer center. Conclusions: The utilization of hypofractionated radiotherapy significantly increased from 2003 to 2011 in the United States, which is presumably influenced by publication of several randomized trials. In 2011, HF-WBI accounted for more than 10% of all external beam radiotherapy for early breast cancer patients. Patient and facility factors impacted the patterns of HF-WBI use. Citation Format: Dezheng Huo, Yasmin Hasan, Katharine Yao. The utilization of hypofractionated breast radiotherapy in the United States between 2003 and 2011 [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-16.