1. Department of Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
2. Department of Family Medicine, Seoul National University Hospital, Seoul 03080, Republic of Korea
3. National Cancer Control Institute, National Cancer Center, Goyang 10408, Republic of Korea
4. Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Science and Technology, School of Medicine, Sungkyunkwan University, Seoul 16419, Republic of Korea
5. Department of Family Medicine and Supportive Care Center, Samsung Medical Center, Seoul 06351, Republic of Korea