Abstract P2-11-14: IMRT use after lumpectomy in early-Stage breast cancer: Patterns of care and cost-consequences
Authors: Roth JA , McDougall J , Halasz L , Fedorenko C , Sun Q , Patel S 
Published: February 2018

Abstract
BACKGROUND
The American Society for Radiation Oncology (ASTRO) issued a Choosing Wisely recommendation (CWr) against use of intensity modulated radiotherapy (IMRT) as part of breast conservation therapy in 2013, noting that “its routine use has not been demonstrated to provide significant clinical advantage”. Also, as IMRT is more expensive vs conventional radiotherapy (cRT), use in this setting may represent wasteful spending. The aims of this study were to characterize: 1) IMRT use immediately preceding the ASTRO CWr, 2) the cost-consequences of IMRT vs. cRT in the year after breast cancer diagnosis, and 3) excess annual U.S. national expenditure on IMRT in this setting.
METHODS
Surveillance Epidemiology and End Results (SEER) records for women age ≥66 years with a first primary diagnosis of Stage I/II breast cancer (2007-2012) were linked with Medicare claims (2007-2013). All cases had coverage for ≥12-months before/after diagnosis (or until death), and to be consistent with the CWr, had lumpectomy 1 month before to 6 months after diagnosis, and radiation therapy within 6 months of lumpectomy. We evaluated receipt of IMRT vs cRT within 1 year of diagnosis in 12 SEER registries. We also calculated mean direct medical expenditure in the year after diagnosis by summing all allowable charges from Medicare claims. Costs were inflated to 2017 USD. We evaluated differences in means by registry using ANOVA and compared mean costs for cases treated with IMRT vs cRT using t-test. We projected excess annual U.S. national expenditure on IMRT (vs. cRT) using the findings from aims 1 & 2 and assuming 209000 incident Stage I/II cases and that 55% receive lumpectomy.
RESULTS
Among 13037 women meeting all inclusion criteria, mean age was 74, 89.0% were white, and 19.8% received IMRT. Table 1 shows the proportions receiving IMRT by SEER registry and mean cost for cases treated with IMRT vs cRT. The proportion with IMRT varied significantly between registries (p&lt;0.001), as did the mean cost for cases treated with IMRT (p&lt;0.001) and cRT (p&lt;0.001). Overall, cost for patients treated with IMRT was significantly higher vs those treated with cRT ($9644, p&lt;0.001). Nationally, we estimated $219 million in annual excess medical expenditure on unnecessary IMRT vs. cRT.
Table 1: Results for Selected RegistriesRegistry% with IMRTMean Cost in Year After Dx ($) IMRTcRTpAll 12 Registries19.84314533501&lt;0.001California15.84624536039&lt;0.001Detroit52.14138735704&lt;0.001Georgia26.44047532257&lt;0.001Iowa3.23884127567&lt;0.001New Jersey25.24731135584&lt;0.001Seattle5.84086332114&lt;0.001
DISCUSSION
From 2007-2013, use of IMRT in Stage I/II breast cancer was substantial (19.8%) and varied significantly across SEER registries. Cases treated with IMRT incurred significantly higher cost ($9644) in the year following diagnosis vs. those treated with cRT. If patterns of care remain similar today, there is potentially as much as $219 million in annual U.S. national expenditure on low-value radiotherapy following lumpectomy. Our findings suggest an opportunity to improve quality in cancer care while reducing expenditure by curbing use of IMRT. Future studies should develop interventions to align practice with ASTRO CW recommendations and reduce variation in practice between regions.
Citation Format: Roth JA, McDougall J, Halasz L, Fedorenko C, Sun Q, Patel S. IMRT use after lumpectomy in early-Stage breast cancer: Patterns of care and cost-consequences [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-11-14.