1. Division of Orthopaedic Oncology, Shizuoka Cancer Center Hospital, 1007 Shimonagakubo, Nagaizumicho, Sunto-gun, Shizuoka 411-8777, Japan, Division of Epidemiology and Prevention, Division of Orthopaedic Oncology, Aichi Cancer Center, 1-1, Kanokoden, Chikusa-ku, Nagoya-City 464-8681, Japan, Division of Clinical Oncology, Nagoya Memorial Hospital, 4-305 Hirabari, Tenpaku-ku, Nagoya-City 468-8520, Japan, Division of Orthopaedic Surgery, Prefectural Aichi Hospital, Kake-machi, Okazaki-City 444-0011, Japan.