1. Department of Radiation Oncology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791‑0280, Japan
2. Division of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791‑0280, Japan
3. Department of Radiology, Ehime University Graduate School of Medicine, Toon, Ehime 791‑0295, Japan
4. Department of Urology, Ehime University Graduate School of Medicine, Toon, Ehime 791‑0295, Japan
5. Department of Urology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791‑0280, Japan