1. Department of Gastroenterology, Southern-Tohoku General Hospital, Koriyama, Japan
2. Department of Minimally Invasive Surgical and Medical Oncology, Fukushima Medical University, Fukushima, Japan
3. Department of Otolaryngology, Southern-Tohoku General Hospital, Koriyama, Japan
4. Department of Gastroenterology, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan