Comparison of a Newly Designed Niti-S D-Weave Combination Covered Stent and Niti-S D-Weave Uncovered Stent for Decompression of Obstructive Colorectal Cancer: A Randomized Prospective Controlled Multicenter Study

Abstract

Background: Uncovered and covered stent have been used for the decompression of gastrointestinal obstruction by cancer with contrary merit and demerit each other. The reobstruction due to tumor ingrowth and migration is the most important problem in stent insertion. To overcome these problems, the Niti-S D-Weave uncovered stent and its double layered covered stent (Taewoong Medical Co., Seoul, Korea) have been developed. The Niti-S D-Weave uncovered stent was designed to have good conformability and less migration, and its double layered covered stent (Niti-S D-Weave combination covered) consists of an interposing PTFE (polytetrafluorethylene) membrane to prevent tumor ingrowth and an outer uncovered nitinol wire to allow the stent to embed itself in the colorectal cancer to prevent migration. Aim: To compare the effectiveness of Niti-S D-Weave combination covered stent and Niti-S D-Weave uncovered stent in the decompression of colon obstruction and the prevention of migration and tumor ingrowth in patients with obstructive colorectal cancer. METHOD: Between June 2004 and May 2005, sixty-seven patients from five medical centers were treated with stent insertion for preoperative decompression or palliative purpose. Patients were randomized to either Niti-S D-Weave combination covered or Niti-S D-Weave uncovered stent group. Results: In sixty-seven patients (40 males; mean age 65.7 ± 14.5 years), twenty nine patients were treated for bridge to surgery and 38 patients for palliation of incurable colorectal cancer. Technical and clinical success rates of both groups were not statistically different (92.9% vs. 100% and 96.4% vs. 97.4% respectively). In surgical finding of colorectal cancer with Niti-S D-Weave combination covered stent, PTFE membrane blocked the tumor ingrowth and the wire of outer layer of stent was embedded into tumor, being expected to prevent migration. As early complications within 7 days after stent insertion, early stent occlusion and migration were not different in both groups. In stent insertion for the palliative purpose, delayed stent occlusion by tumor ingrowth occurred in 5 of 22 patients (22.7%) with Niti-S D-Weave uncovered stent and 1 of 16 (6.3%) with Niti-S D-Weave combination covered stent. Delayed stent migration occurred in only 3 (18.8%) patients with Niti-S D-Weave combination covered stent. However, the rates of delayed stent occlusion and migration were not statistically different in both groups. Conclusion: Newly designed double-layered covered stent (Niti-S D-Weave combination covered stent) could be useful in preventing both the stent migration and the tumor ingrowth after stent insertion.