Sungkyunkwan University - Department of Family Medicine/Supportive Care Center, Sungkyunkwan University - Department of Family Medicine/Supportive Care Center, Seoul National University - Department of Internal Medicine, Catholic University of Korea - Department of Medical Statistics, Catholic University of Korea - Department of Medical Statistics, Sungkyunkwan University - Department of Family Medicine/Supportive Care Center, Chungbuk National University - College of Medicine, National Cancer Center, Korea, National Health Insurance Service, Chungbuk National University - College of Medicine and Harvard University - Department of Society, Human Development, and Health