Acute colorectal obstruction has been reported to occur in 7 - 29% of all colorectal malignancies, but emergent surgical decompression is associated with high morbidity and mortality rates. Recently, self-expandable metal stents(SEMS) have been suggested as an alternative to surgery and effectively decompress the colonic obstruction and allow for bowel preparation and elective surgery. Theoretically, SEMSs are classified into uncovered stents and covered stents. Covered stents have the advantage of less frequent stent occlusion by tumor in-growth and the disadvantage of a high risk of stent migration, whereas uncovered stents are associated with less stent migration, although they appear to be more prone to tumor ingrowth. To overcome the drawbacks of conventional stents, a double-layered combination covered stent was developed. In the present study, the investigators evaluated the efficacy and safety of the newly designed covered stent by comparing it with the uncovered stent in patients with malignant colorectal obstruction.

Inclusion Criteria:

• 20~85-year-old patients with malignant colorectal obstruction either by primary CRC or extracolonic malignancy
• Patients with clinical obstructive symptoms confirmed by CT or colonoscopy

Exclusion Criteria:

• Patients with evidence of bowel perforation or peritonitis
• Cause of obstruction other than malignancy (bowel adhesion or benign stricture)
• Multiple stricture
• Lower rectal cancer obstruction (AV <5cm)