A Prospective Multicenter Study of Self-expandable Metallic Stents As a Bridge To Surgery for Malignant Colorectal Obstruction in Japan: Efficacy and Safety in 313 Patients

Shuji Saito, MD¹, Hitoshi Sekido, MD¹, Shuntaro Yoshida, MD², Hiroyuki Isayama, MD³, Takeaki Matsuzawa, MD⁴, Toshio Kuwai, MD⁵, Iruru Maetani, MD⁶, Mamoru Shimada, MD⁷, Tomonori Yamada, MD⁸, Masafumi Tomita, MD⁹, Koichi Koizumi, MD¹⁰, Nobuto Hirata, MD¹¹, Hideki Kanazawa, MD¹², Satoshi Ikeda, MD¹³, Ken Konishi, MD¹⁴, Tomio Hirakawa, MD¹⁵, Rika Kyo, MD¹⁶, Toshiyuki Enomoto, MD¹⁷, Yoshihisa Saida, MD¹⁷. ¹Department of Surgery, National Hospital Organization Yokohama Medical Center, ²Department of Endoscopy and Endoscopic Surgery, Graduate School of Medicine, The University of Tokyo, ³Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, ⁴Dept. of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, ⁵Dept. of Gastroenterology, National Hosp. Organization Kure Medical Center and Chugoku Cancer Center, ⁶Div. of Gastroenterology and Hepatology, Dept. of Internal Medicine Toho Univ. Ohashi Medical Center, ⁷Department of Surgery, Moriguchi Keijinkai Hospital, ⁸Department of Gastroenterology, Japanese Red Cross Nagoya Daini Hospital, ⁹Department of Surgery, Kishiwada Tokushukai Hospital, ¹⁰Dept. of Gastroenterology, Tokyo Metropolitan Cancer and Infectious disease Center Komagome Hospital, ¹¹Department of Gastroenterology, Kameda Medical Center, ¹²Department of Surgery, National Hospital Organization Sagamihara Hospital, ¹³Department of Surgery, Hiroshima Prefectural Hospital, ¹⁴Department of Gastroenterological Surgery, Higashiosaka City General Hospital, ¹⁵Department of Gastroenterology, Yao Tokushukai General Hospital, ¹⁶Department of Gastroenterology, Saiseikai Yokohamashi Nanbu Hospital, ¹⁷Department of Surgery, Toho University Ohashi Medical Center

INTRODUCTION: Endoscopic stenting with a self-expandable metallic stent (SEMS) as a bridge to surgery (BTS) is a widely accepted procedure for malignant colonic obstruction; however, it has not been approved under Japanese insurance system. We started to conduct this prospective feasibility study immediately after this procedure was approved for coverage by the national health insurance in January 2012.

METHODS AND PROCEDURES: Our objectives were to estimate the safety and feasibility of SEMS placement as a BTS for malignant colorectal obstruction in Japan. We conducted a prospective, observational, single-arm and multicenter clinical trial from March 2012 to October 2013. Forty-two facilities participated in this study. Each patient was treated with an uncovered WallFlex Enteral Colonic Stent (Boston Scientific Corporation). Patients undergoing the stenting as a BTS were followed until discharge after surgery. The clinical success of the BTS was defined as having adequate passage of stool from stenting until surgery without any stent-related complications and without the need for endoscopic reintervention or emergency surgery.

RESULTS: A total of 518 consecutive patients were enrolled in this study. Five patients were excluded because of loose stenosis, adhesive small bowel obstruction or placement of another type of SEMS. The remaining 513 patients were the per-protocol cohort. The intention for treatment was as a BTS in 313 patients (61%), and palliative in 200 patients. Of the 313 BTS patients, 69% had localized colorectal cancer without distant metastasis. The stent could be released in 306 patients, and the technical and clinical success rates were 98%(306/313) and 92%(288/313). Elective surgery was performed in 301 patients (98%) and emergency surgery was performed in five for treatment of a complication. The overall preoperative complication rate was 7.8%(24/306). Major complications included perforation in 2.0%:6/306 patients; 3 with clinical perforation and 3 with silent perforation (the stent was exposed in the abdominal cavity intraoperatively), persistent colonic obstruction in 1.3%(4/306), septic shock in 0.3%(1/306) and stent migration in 1.3%(4/306). The median time from SEMS insertion to surgery was 16 days. Open surgery was performed in 121 cases and laparoscopic surgery was performed in 185. Conversion to open surgery from laparoscopic surgery was required in 19 out of 185(10%). The tumor could be resected in 298 patients. The primary anastomosis rate was 92%(281/306). The rate of anastomotic leakage was 4%(12/281). The overall stoma creation rate was 10%(32/306); with 17 of 32 patients undergoing the Hartmann operation, nine receiving a diverting stoma, and the remaining six patients receiving colostomy alone without resection of the tumor. The median duration of hospitalization after surgery was 12 days. The postoperative overall morbidity rate was 17%(50/302). The hospital postoperative mortality was 0.7%(2/306). These two patients both died from progression of cancer.

CONCLUSION: This large, multicenter, prospective study demonstrates the feasibility of SEMS placement as a BTS for malignant colorectal obstruction. SEMS serves as a safe and effective bridge to surgical treatment with acceptable stoma creation and complication rates in patients with acute malignant colonic obstruction, allowing elective surgery to be performed with a primary anastomosis in most patients.