Clinical implementation and feasibility of long-course fractionated MR-guided chemoradiotherapy for patients with esophageal cancer: An R-IDEAL stage 1b/2a evaluation of technical innovation

• DOI: 10.1016/j.ctro.2022.03.008
• Publication Date: 2022-03-16T22:22:53Z
• Authors: M.R. Boekhoff; R. Bouwmans; P.A.H. Doornaert; M.P.W. Intven; J.J.W. Lagendijk; A.L.H.M.W. van Lier; M.J.A. Rasing; S. van de Ven; G.J. Meijer; S. Mook
• Keywords: Chemoradiotherapy; Ablative case

This R-Ideal stage 1b/2a study describes the workflow and feasibility of long-course fractionated online adaptive MR-guided chemoradiotherapy with reduced CTV-to-PTV margins on 1.5T MR-Linac for patients esophageal cancer.Patients cancer scheduled to undergo chemoradiation were treated a MR-Linac. Daily MR-images acquired contour adaptation replanning. Contours manually adapted match daily anatomy an isotropic margin 6 mm was applied. Time recorded all individual steps in workflow. Feasibility patient tolerability defined as on-table time ≤60 min completion >95% fractions MR-Linac, respectively. Positioning verification post-treatment MRIs retrospectively analyzed dosimetric parameters compared standard non-adaptive conventional treatment plans.Nine chemoradiation; eight received 41.4 Gy 23 one 50.4 28 fractions. Four planned whereas two >5% rescheduled linac reasons discomfort. A total 183 (86%) 212 successfully delivered Three ended prematurely due technical issues 26 downtime (n = 10), logistical 3) or discomfort 13).The median per fraction 53 (IQR 3 min). plans had similar target coverage, dose organs-at-risk significantly (26% 12% reduction mean lung heart dose, respectively).Daily PTV is moderately feasible results better sparing lungs. Future studies should focus further optimization acceleration current