1. Department of Urology, Faculty of Medicine and Graduate School of Comprehensive Human Science, University of Tsukuba, Tsukuba, Ibaraki 305‑8575, Japan
2. Department of Urology, Aichi Cancer Center Hospital, Nagoya, Aichi 464‑8681, Japan
3. International Medical Center, University of Tsukuba Affiliated Hospital, Tsukuba, Ibaraki 305‑8576, Japan