1. Cancer Policy Branch, National Cancer Control Institute, National Cancer Center, Goyang-si, Korea;
2. Department of Internal Medicine, Seoul National University Boramae Hospital, Seoul, Korea;
3. Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea;
4. National Cancer Control Institute, National Cancer Center, Goyang-si, Korea; and
5. Health Insurance Review Agency, Wonju-si, Korea