1. Division of International Health Policy Research, Institute for Cancer Control, National Cancer Center , 5-1-1 Tsukiji, Chuo-Ku, Tokyo 104-0045 , Japan
2. Faculty of International Liberal Arts, Juntendo University , 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421 , Japan
3. Department of Medical Statistics, Research & Development Center Osaka Medical and Pharmaceutical University , 2-7 Daigaku-machi, Takatsuki City, Osaka 569-8686 Japan