Comparison of the efficacy of self-expandable metallic stents in colorectal obstructions caused by extracolonic malignancy and colorectal cancer.

The current study aimed to compare the safety and effectiveness of self-expandable metallic stent placement among patients with extracolonic malignancy and those with colorectal cancer. Patient information, technical and clinical success rates and complication rates were compared between patients with colorectal cancer and extracolonic malignancy. The Kaplan-Meier method was used to compare the time elapsed before the onset of complications. Risk factors for re-obstruction in patients with self-expandable metallic stents were evaluated by multivariate analysis. A total of 68 patients who underwent self-expandable metallic stent placement at Saiseikai Niigata Hospital between January 2012 and September 2019 were included. The clinical success rate was significantly different between the colorectal cancer (96.6%) and extracolonic malignancy (66.7%) groups (P=0.01). The incidence of complications was significantly higher in the extracolonic malignancy group (66.7%) than in the colorectal cancer group (25.4%; P=0.02). Additionally, the time elapsed before the onset of complications was shorter in the extracolonic malignancy group than in the colorectal cancer group (P=0.0008). Risk factors for re-obstruction were higher in the extracolonic malignancy group [odds ratio, 7.76 (1.02-57.2)] than in the palliative stent placement group [odds ratio, 5.45 (1.01-29.5); P=0.04]. In extracolonic malignancy, self-expandable metallic stent placement was associated with lower clinical success rates and increased risk of complications. The time elapsed before the onset of complications was short, and extracolonic malignancy was a risk factor for re-obstruction, suggesting that the placement of self-expandable metallic stents for malignant colorectal obstruction in extracolonic malignancy is not optimal.