1. Department of Family Medicine, Dankook University Hospital, Cheonan, Korea; Department of Family Medicine, Seoul National University College of Medicine, Seoul, Korea
2. Department of Family Medicine, National Cancer Center, Goyang, Korea
3. Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
4. National Cancer Control Institute, National Cancer Center, Goyang, Korea
5. Department of Family Medicine, National Cancer Center, Goyang, Korea; National Cancer Control Institute, National Cancer Center, Goyang, Korea