1. Department of Radiotherapy, West German Cancer Center, University Hospital, University of Duisburg-Essen, Essen, Germany
2. Department of Medical Oncology, Ruhrlandklinik, West German Cancer Center, University Hospital, University of Duisburg-Essen, Essen, Germany
3. Department of Thoracic Surgery, Ruhrlandklinik, University Hospital, University of Duisburg-Essen, Essen, Germany