Ichiro Takemasa1,2, Koichi Okuya3,4, Kenji Okita3,4, Masayuki Ishii3,4, Masaaki Ito3,5, Kay Uehara3,6, Tsuyoshi Konishi3,7, Shigeki Yamaguchi3,8, Masafumi Inomata3,9, Shintaro Sugita10, Tadashi Hasegawa10, Atsushi Ochiai11, Yoshiharu Sakai3,12, Masahiko Watanabe3,13. 1. The Japan Society for Endoscopic Surgery, Tokyo, Japan. itakemasa@sapmed.ac.jp. 2. Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, S1 W16, Chuo-ku, Sapporo, 060-8543, Japan. itakemasa@sapmed.ac.jp. 3. The Japan Society for Endoscopic Surgery, Tokyo, Japan. 4. Department of Surgery, Surgical Oncology and Science, Sapporo Medical University, S1 W16, Chuo-ku, Sapporo, 060-8543, Japan. 5. Department of Colorectal Surgery, National Cancer Center Hospital East, Kashiwa, Japan. 6. Division of Surgical Oncology, Department of Surgery, Nagoya University Graduate School of Medicine, Nagoya, Japan. 7. Department of Gastroenterological Surgery, Cancer Institute Hospital, Japanese Foundation for Cancer Research, Tokyo, Japan. 8. Department of Gastroenterological Surgery, Saitama Medical University International Medical Center, Hidaka, Japan. 9. Department of Gastroenterological and Pediatric Surgery, Oita University Faculty of Medicine, Yufu, Japan. 10. Department of Surgical Pathology, Sapporo Medical University, Sapporo, Japan. 11. Division of Biomarker Discovery, Exploratory Oncology Research and Clinical Trial Center, National Cancer Center, Kashiwa, Japan. 12. Department of Surgery, Graduate School of Medicine, Kyoto University, Kyoto, Japan. 13. Department of Surgery, Kitasato Institute Hospital, Tokyo, Japan.
Abstract
PURPOSE: A circumferential resection margin (CRM) > 1 mm is a surrogate marker of oncologic outcomes in rectal cancer patients. In Japan, because the mesentery is removed from the rectum, the CRM cannot be measured. This multicenter prospective study evaluates the feasibility of a resected specimen processing method that allows CRM measurement. METHODS: Fifty patients with rectal cancer were enrolled. Resected specimens were processed as previously reported. The primary outcomes were CRM measurement and the rate of CRM positivity. The secondary outcomes were the quality of total mesorectal excision, the possibility to visualize and sample the tumor, the number of harvested lymph nodes, and comparison between the pathological CRM and preoperative mesorectal fascia (MRF) involvement. This study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry under identification number UMIN000031735. RESULTS: The CRM was measurable in all patients and found to be positive in three (6%). We confirmed tumor localization, sampled the tumor, and measured the distal margin in all patients. A median of 20 lymph nodes were harvested. The concordance rate between preoperative MRF involvement and pathological CRM status was 90%. CONCLUSION: A semi-opened rectal specimen with transverse slicing is a feasible method for measuring the CRM.
PURPOSE: A circumferential resection margin (CRM) > 1 mm is a surrogate marker of oncologic outcomes in rectal cancer patients. In Japan, because the mesentery is removed from the rectum, the CRM cannot be measured. This multicenter prospective study evaluates the feasibility of a resected specimen processing method that allows CRM measurement. METHODS: Fifty patients with rectal cancer were enrolled. Resected specimens were processed as previously reported. The primary outcomes were CRM measurement and the rate of CRM positivity. The secondary outcomes were the quality of total mesorectal excision, the possibility to visualize and sample the tumor, the number of harvested lymph nodes, and comparison between the pathological CRM and preoperative mesorectal fascia (MRF) involvement. This study was registered in the University Hospital Medical Information Network (UMIN) Clinical Trials Registry under identification number UMIN000031735. RESULTS: The CRM was measurable in all patients and found to be positive in three (6%). We confirmed tumor localization, sampled the tumor, and measured the distal margin in all patients. A median of 20 lymph nodes were harvested. The concordance rate between preoperative MRF involvement and pathological CRM status was 90%. CONCLUSION: A semi-opened rectal specimen with transverse slicing is a feasible method for measuring the CRM.