Use of Pancreatic Stereotactic Ablative Radiotherapy (PSART) in U.S. Community Cancer Clinics

Abstract

<h3>Purpose/Objective(s)</h3> Pancreatic stereotactic ablative radiotherapy (PSART) is developing as an alternative to conventional fractionation to improve multi-modal options for care. Guidelines state that PSART should be done in high-volume centers or on trials because of the technical complexity of this procedure risk of causing injury to normal organs. However, patients frequently rely on community radiation centers to access treatment. We audited use of PSART in a group of community-based clinics to examine practice and identify opportunities for advancement. <h3>Materials/Methods</h3> We conducted an IRB approved retrospective analysis of Stereotactic radiotherapy at 123 community-based clinics in the US by querying a prospective in-house record system. Chart review was performed for outcomes. Doses were reported as biologically effective dose (BED) and equivalent dose at 2Gyper fraction (EQD2). Data was analyzed using data management and decision management software. <h3>Results</h3> Among 15,797 patients who were treated with SART from 01/ 2017 to 11/2021, only 119 (0.75%) were PSART of which 42 were palliative. Annual case volume was over time. Motion management was done in 104 (87.4%) of patients. Most patients were treated with either volumetric modulated arc therapy n=90 (75.6%) or helical 3-D CRT and IMRT system n=14(11.8%). Among 77 curative patients, median and modal number of fractions was 5 in 69 (89.6%) of patients (range1-5); commonest BEDs were 32-51.9, 52- 71.9, and 72-91.9 in 28.6%, 35.1%, and 31.2% respectively (range 14.4 - 132); commonest EQD2s were <40, 41-50, and 61-60 in 31.2%, 27.3, %, and 33.8% respectively (range 112 - 110). At median follow up 8.4 months (range 0.3- 50.5) for curative patients, locoregional status was controlled in 34(44.2%), recurrent in 7 (9.1%), and unknown in 36 (46%); 34 (44.2%) were alive, 32(41.6%) had died and 11(14.3%) was unknown. There was a trend for improved survival with BED >= 52 Gy (p=0.08). At median follow up 6.7months (range 1.0- 31) for palliative patients, locoregional status was controlled in 17(40.5%), recurrent in 4 (9.5%) and unknown in 21 (50%); 14 (33.3%) were alive, 22 (52.4%) had died and 6(14.3%) was unknown. Toxicity data reporting was limited. <h3>Conclusion</h3> Rate of PSART practice was low and stable over the five-year period with appropriate technology but wide variation in dose. We have initiated programs to increase access to high-quality PSART: education of community multidisciplinary teams, updated clinical guidelines and dose-constraints, prospective collection of patient-reported outcomes, and investment in technology.