1. Department of Thoracic Surgery, University Hospitals Leuven and KU Leuven, Leuven, Belgium
2. Clinical Operational Research Unit, Department of Mathematics and Physical Sciences, University College London, London, UK
3. Department of Gastrointestinal and Liver Diseases, Digestive Oncology Unit, University Hospitals Leuven and KU Leuven, Leuven, Belgium
4. Centre for Trials Research, Cardiff University, Cardiff, UK