Impact of the American Tax Payer Relief Act on stereotactic radiosurgery utilization in the United States

Introduction Single-fraction stereotactic radiosurgery (SRS) is delivered predominantly via two modalities: Gamma Knife, and linear accelerator (LINAC). Implementation of the American Tax Payer Relief Act (ATRA) in 2013 represented the first time limitations specifically targeting SRS reimbursement were introduced into federal law. The subsequent impact of the ATRA on SRS utilization in the United States (US) has yet to be examined. Methods The National Cancer Database from 2010-2016 identified brain metastases patients from non-small cell lung cancer throughout the US having undergone SRS. Utilization between GKRS and LINAC was assessed before (2010-2012), during (2013-2014) and after (2015-2016) ATRA implementation. Results In 2013, there was a substantial decrease of LINAC SRS in favor of GKRS in non-academic centers. Over the 3-year span immediately preceding ATRA implementation, 39% of all eligible SRS cases received LINAC. There was a modest decrease in LINAC utilization over the 2 years immediately following ATRA implementation (35%), followed by an increase over the next two years (40%). SRS modality showed differences over the three time periods (unadjusted, p = 0.043), primarily in non-academic centers (unadjusted, p = 0.003). Conclusions ATRA implementation in 2013 caused an initial spike in Gamma Knife SRS utilization, followed by a decline to rates similar to the years before implementation. These findings indicate that the ATRA provision mandating Medicare reduction of outpatient payment rates for Gamma Knife to be equivalent with those of LINAC SRS had a significant shortterm impact on the radiosurgical treatment of metastatic brain disease throughout the US, serving as a reminder of the importance/impact of public policy on treatment modality utilization by physicians and hospitals.