ESTRO 2023 - Abstract Book

S1563

Digital Posters

ESTRO 2023

PO-1831 Heterogeneously Hypo-fractionated RT for LA-NSCLC (the HERAN trial): Clinical treatment plan results

L. Hoffmann 1,4 , A. Appelt 2,3 , M.M. Knap 1 , D.S. Møller 1,4 , T.S. Hansen 5 , C. Christiansen 5 , M.D. Lund 6 , M. Nielsen 7 , T.B. Nielsen 7 , T. Schytte 8,9 , R. Thing 10 , A.A. Khalil 1,11 1 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark; 2 University of Leeds , Leeds Institute of Medical Research at St James's, Leeds, United Kingdom; 3 St James's University Hospital, Leeds Cancer Centre, Leeds, United Kingdom; 4 Aarhus University, Department of Clinical Medicine, Faculty of Health Sciences, Aarhus, Denmark; 5 Vejle Hospital, University Hospital of Southern Denmark, Department of Oncology, , Vejle, Denmark; 6 Vejle Hospital, University Hospital of Southern Denmark, , Department of Oncology, Vejle, Denmark; 7 Odense University Hospital, Laboratory of Radiation Physics, Odense, Denmark; 8 Odense University hospital, Department of Oncology, Odense, Denmark; 9 University of Southern Denmark, Department of Clinical Research, Odense, Denmark; 10 Vejle Hospital, University Hospital of Southern Denmark, Department of Oncology, Vejle, Denmark; 11 Faculty of Health Sciences, Department of Clinical Medicine, Aarhus, Denmark Purpose or Objective Treatment options for frail patients with locally-advanced non-small cell lung cancer (LA-NSCLC) unfit for standard chemoradiotherapy regimes (60-66Gy in 30-33 fractions) are meagre. A shorter radical radiotherapy schedule with heterogeneous dose escalation to the gross tumour, keeping normal tissue toxicity low, can be a favourable option. The national Danish HERAN trial (NCT03742687) aims to test this approach. We report on clinical dose planning results for the first 104 patients treated on the trial. Materials and Methods HERAN is a non-randomised multicentre phase II feasibility study, enrolling patients with inoperable NSCLC stage IIA-IV disease not candidates for standard chemoradiotherapy. Gross tumour volumes of primary tumours (GTV-T) and lymph nodes with a diameter >3cm (GTV-Nlarge) are treated with mean doses of up to 66Gy in 24 fractions, with overall Dmax ≤ 74Gy. Dose to the remaining targets (GTV-N, CTV and PTV) must be covered by 95% of 50Gy, but is not intentionally increased above 50Gy. Dose escalation is limited by constraints to PTV-CTV (volume of PTV subtracted CTV) and organs at risk (OAR). The dose to the 1cm3 receiving the highest dose (D1cc) of PTV-CTV and 1cm3 of tissue outside PTV may increase to 65Gy. OAR constraints are Spinal Cord D0.05cc<45Gy; Lungs Dmean<20Gy, V20Gy<35%; Heart V30Gy<40%; and Esophagus D1cc<58Gy.