1. Department of Family Medicine, Gil Medical Center, Gachon University College of Medicine, Incheon, Korea
2. Division of Oncology, Department of Internal Medicine, Kosin University Gospel Hospital, Busan, Korea
3. Department of Family Medicine, Korea University Guro Hospital, Seoul, Korea
4. Division of Oncology, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Korea
5. Department of Family Medicine, Incheon St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Incheon, Korea
6. Oncology Division, Department of Internal Medicine, Yeungnam University College of Medicine, Daegu, Korea