1. Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
2. Department of Medicine, Pulmonary Service, Section of Interventional Pulmonology, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
3. Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
4. Department of Epidemiology & Biostatistics, Memorial Sloan Kettering Cancer Center, New York, NY 10021, USA
5. New York Proton Center, New York, NY 10035, USA
6. Department of Radiation Oncology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, German Cancer Consortium (DKTK), Partner Site DKTK-Freiburg, Robert-Koch-Strasse 3, 79106 Freiburg, Germany