Treatment planning comparison in the PROTECT-trial randomising proton versus photon beam therapy in oesophageal cancer: Results from eight European centres.

Matthew Clarke, Ditte Sloth Møller, Damien C Weber, Sabine Visser, Gloria Vilches-Freixas, Esther G C Troost, Melissa Thomas, Ganesh Radhakrishna, Marianne Nordsmark, Owen Nicholas, Luke Murray, Christina T Muijs, Sebastian Makocki, Lone Hoffmann, Erik W Korevaar, Ryan Hulley, Karin Haustermans, Francesca Fiorini, Mai Lykkegaard Ehmsen, Gilles Defraene, Richard Canters, Rebecca Bütof, Nicola Bizzocchi, Maaike Berbee, Muhammad Shamshad, Hanna Mortensen

Journal: Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology 2022;172():32-41

PMID: 35513132

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Abstract

PURPOSE

To compare dose distributions and robustness in treatment plans from eight European centres in preparation for the European randomized phase-III PROTECT-trial investigating the effect of proton therapy (PT) versus photon therapy (XT) for oesophageal cancer.

MATERIALS AND METHODS

All centres optimized one PT and one XT nominal plan using delineated 4DCT scans for four patients receiving 50.4 Gy (RBE) in 28 fractions. Target volume receiving 95% of prescribed dose (V95%) should be >99%. Robustness towards setup, range, and respiration was evaluated. The plans were recalculated on a surveillance 4DCT (sCT) acquired at fraction ten and robustness evaluation was performed to evaluate the effect of respiration and inter-fractional anatomical changes.

RESULTS

All PT and XT plans complied with V95% >99% for the nominal plan and V95% >97% for all respiratory and robustness scenarios. Lung and heart dose varied considerably between centres for both modalities. The difference in mean lung dose and mean heart dose between each pair of XT and PT plans was in median [range] 4.8 Gy [1.1;7.6] and 8.4 Gy [1.9;24.5], respectively. Patients B and C showed large inter-fractional anatomical changes on sCT. For patient B, the minimum V95% in the worst-case robustness scenario was 45% and 94% for XT and PT, respectively. For patient C, the minimum V95% was 57% and 72% for XT and PT, respectively. Patient A and D showed minor inter-fractional changes and the minimum V95% was >85%.

CONCLUSION

Large variability in dose to the lungs and heart was observed for both modalities. Inter-fractional anatomical changes led to larger target dose deterioration for XT than PT plans.

Address: Department of Medical Physics, Aarhus University Hospital, Denmark; Dept. of Clinical Medicine, Faculty of Health Sciences, Aarhus University, Denmark. Electronic address: [email protected].; Danish Center for Particle Therapy, Aarhus University Hospital, Denmark.; Department of Medical Physics, Aarhus University Hospital, Denmark; Dept. of Clinical Medicine, Faculty of Health Sciences, Aarhus University, Denmark; Danish Center for Particle Therapy, Aarhus University Hospital, Denmark.; Department of Radiation Oncology (Maastro), GROW School for Oncology and Reproduction, Maastricht University Medical Centre+, The Netherlands.; Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland.; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany.; KU Leuven - University of Leuven - Department of Oncology - Laboratory of Experimental Radiotherapy, Belgium.; Rutherford Cancer Centre, Shinfield, Reading, UK.; KU Leuven - University of Leuven - Department of Oncology - Laboratory of Experimental Radiotherapy, Belgium; University Hospitals Leuven, Department of Radiation Oncology, Belgium.; Christie Medical Physics and Engineering, The Christie NHS Foundation Trust, Manchester, UK.; Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, The Netherlands.; South West Wales Cancer Centre, Swansea University Board and Swansea University Medical School, UK.; Department of Oncology, Aarhus University Hospital, Denmark.; Department of Radiotherapy and Radiation Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Germany; OncoRay - National Center for Radiation Research in Oncology, Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Helmholtz-Zentrum Dresden - Rossendorf, Germany; Institute of Radiooncology - OncoRay, Helmholtz-Zentrum Dresden-Rossendorf, Germany; German Cancer Consortium (DKTK), Partner Site Dresden, and German Cancer Research Center (DKFZ), Heidelberg, Germany; National Center for Tumor Diseases (NCT), Partner Site Dresden, Germany: German Cancer Research Center (DKFZ), Heidelberg, Germany; Faculty of Medicine and University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; Helmholtz Association/Helmholtz-Zentrum Dresden - Rossendorf (HZDR), Dresden, Germany.; Center for Proton Therapy, Paul Scherrer Institut, Villigen, Switzerland; Radiation Oncology Department, University Hospital Zurich, Zurich, Switzerland.; Department of Medical Physics, Aarhus University Hospital, Denmark; Dept. of Clinical Medicine, Faculty of Health Sciences, Aarhus University, Denmark.

DOI: 10.1016/j.radonc.2022.04.029

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MeSH Terms: Esophageal Neoplasms, Humans, Proton Therapy, Protons, Radiotherapy Planning, Computer-Assisted, Radiotherapy, Intensity-Modulated