Jae Sik Kim and Kyubo Kim contributed equally to this study.

Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea

Jae Sik Kim, Kyung Hwan Shin, Kyung Su Kim & In Ah Kim

Department of Radiation Oncology, Ewha Womans University College of Medicine, Seoul, Korea

Kyubo Kim & Wonguen Jung

Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea

Seock-Ah Im & Jee Hyun Kim

Department of Internal Medicine, Chung-Ang University College of Medicine, Seoul, Korea

Hee-Jun Kim

Department of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul, Korea

Yong Bae Kim & Jee Suk Chang

Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

Doo Ho Choi

Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea

Yeon Hee Park

Proton Therapy Center, National Cancer Center, Seoul, Korea

Dae Yong Kim & Tae Hyun Kim

Department of Radiation Oncology, Seoul St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea

Byung Ock Choi & Sea-Won Lee

Department of Radiation Oncology, Eunpyeong St. Mary’s Hospital, The Catholic University of Korea, Seoul, Korea

Sea-Won Lee

Department of Radiation Oncology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, Korea

Suzy Kim

Department of Radiation Oncology, Chungnam National University College of Medicine, Daejeon, Korea

Jeanny Kwon

Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Changwon Hospital, Changwon, Korea

Ki Mun Kang

Department of Radiation Oncology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Gwangju, Korea

Woong-Ki Chung

Department of Radiation Oncology, Dongnam Institute of Radiological and Medical Sciences, Busan, Korea

Kyung Su Kim

Department of Radiation Oncology, Ansan Hospital, Korea University Medical College, Ansan-Si, Korea

Won Sup Yoon

Department of Radiation Oncology, Keimyung University Dongsan Medical Center, Keimyung University School of Medicine, Daegu, Korea

Jin Hee Kim

Department of Radiation Oncology, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju-Si, Korea

Jihye Cha

Department of Radiation Oncology, Chosun University Medical School, Gwangju, Korea

Yoon Kyeong Oh

Department of Radiation Oncology, Seoul National University Bundang Hospital, Gumi-Ro 173, 82 Beon-Gil, Bundang Gu, Seongnam, 13620, Republic of Korea

In Ah Kim

JSK contributed to formal analysis, methodology, visualization, writing of the original draft, and writing, reviewing, and editing of the manuscript. KK contributed to formal analysis, methodology, supervision, writing of the original draft, and writing, reviewing, and editing of the manuscript. WJ, KHS, SAI, HJK, YBK, JSC, JHK, DHC, YHP, DYK, THK, BOC, SWL, SK, JK, KMK, WKC, KSK, WSY, JHK, JC, and YKO contributed to investigation and writing, reviewing, and editing of the manuscript. IAK contributed to conceptualization, supervision, and writing, reviewing, and editing of the manuscript. All the authors have read and approved the final version of the manuscript.