1. Hiroshima High‐Precision Radiotherapy Cancer Center Hiroshima Japan
2. Department of Radiation Oncology Institute of Biomedical & Health Sciences Hiroshima University Hiroshima Japan
3. Department of Radiation Oncology Niigata Cancer Center Hospital Niigata Japan
4. Department of Gastroenterology Yokohama City University Medical Center Yokohama Japan
5. Department of Gastroenterology and Hepatology Nagasaki University Graduate School of Biomedical Sciences Nagasaki Japan
6. Department of Radiation Oncology Yamanashi University Hospital Yamanashi Japan
7. Department of Radiation Oncology National Cancer Center Hospital Japan Tokyo Japan
8. Department of Radiation Oncology Kobe City Medical Center General Hospital Hyogo Japan
9. Department of Radiation Oncology Hokkaido University Faculty of Medicine Sapporo Japan
10. Department of Radiation Oncology Kyusyu University Hospital Fukuoka Japan
11. Department of Radiation Oncology Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital Tokyo Japan
12. Department of Radiation Oncology Tsukuba University Hospital Ibaraki Japan
13. Department of Radiation Oncology Kyoto University Hospital Kyoto Japan
14. Department of Radiation Oncology Aichi Cancer Center Hospital Nagoya Japan
15. Department of Radiation Oncology Kochi University Hospital Kochi Japan
16. Department of Radiation Oncology Showa University School of Medicine Tokyo Japan