1. Obstetrics and Gynecology, Odawara Municipal Hospital, Odawara, Kanagawa, Japan
2. Department of Obstetrics and Gynecology, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
3. Nursing Department, Odawara Municipal Hospital, 46 Kuno, Odawara, Kanagawa, Japan
4. Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
5. Department of Biostatistics, Yokohama City University, Yokohama, Kanagawa, Japan