# Long‐term results of palliative placement of very low‐axial force self‐expandable metallic stents for malignant colorectal obstruction

## TL;DR

This study shows that using very low axial force stents for colorectal cancer blockage is safe and effective for long-term palliative care.

## Contribution

The study evaluates the long-term safety and effectiveness of very low axial force stents in malignant colorectal obstruction.

## Key findings

- The 1-year survival rate after stent placement was 37.8%.
- Cumulative patency rates were 93.6%, 84.2%, and 75.8% at 3, 6, and 12 months.
- Major adverse events were low, with perforation at 2.5% and no cases after bevacizumab use.

## Abstract

Stent placement is a standard option for palliative decompression in patients with malignant colorectal obstruction. Long‐term stent placement is associated with perforation, migration, and stent occlusion. Perforation is associated with life expectancy. Several studies have shown that stents with a high axial force (AF), which is defined as the force required to maintain the stent straight after it has bent, are associated with a higher perforation rate. Therefore, we evaluated the long‐term outcomes of using a very low AF stent (Niti‐S Enteral Colonic Uncovered stent D‐type) for palliative purposes.

Eighty‐one consecutive patients with malignant colorectal obstruction in 33 medical institutions were evaluated. A stent with very low AF was placed using an endoscope system. We evaluated the adverse events (including perforation, migration, and stent occlusion), 1‐year survival rate, and cumulative patency rate. Univariate analysis was conducted using Fisher's exact test. The overall survival and cumulative patency rates were assessed using the Kaplan–Meier method.

The 1‐year cumulative survival rate was 37.8% after stent placement. The 3‐month, 6‐month, and 1‐year cumulative patency rates after stenting were 93.6%, 84.2%, and 75.8%, respectively. The major adverse events included stent migration (6.2%), stent occlusion (9.9%), and perforation (2.5%). Chemotherapy was administered in 26 cases (32.1%) after stenting, and bevacizumab was administered in five cases. However, no cases of perforation occurred following bevacizumab administration.

Our results suggest that very low AF stents are safe and effective. Therefore, they may be a suitable option for applications, such as palliation. (UMIN 000011304)