Safety and Efficacy of a modified small-caliber-tip transparent hood in endoscopic decompression for obstructive colorectal cancer

Interventions: Endoscopic decompression using modified ST hood (Replaced with conventional hood only if failure occurs with modified ST hood within a specified time). Endoscopic decompression using conventional hood (Replaced with modified ST hood only if failure occurs with conventional hood within a specified time). Primary outcome(s): Success rate and procedure time to pass the guide-wire through the colorectal stricture site. Study Design: Parallel Randomized