Endoluminal photodynamic therapy with a photoreactive stent‐based catheter system to treat malignant colorectal obstruction

Photodynamic therapy (PDT) using photosensitizer (PS)-embedded silicone membrane-covered self-expandable metallic stents (SEMSs) can function in palliative therapeutic option for malignant gastrointestinal tract obstruction. However, stent-related complications should be considered, and accurate delivery of light sources is technically difficult. Here, a Chlorin e6 (Ce6)-an embedded stent-based catheter is developed to improve its therapeutic efficacy and safety. PDT using Ce6-embedded stent successfully induced cell death of colorectal cancer cell line. PDT-treated liver tissues showed an increase in ablation depth in proportion to irradiation energy, and 600 J/cm² demonstrates an even and sufficient ablation depth. Endoluminal PDT using the Ce6-embedded stent-based catheter was technically successful in a rat colon model without procedure-related complications such as colonic perforation or stricture formation. The results in colonoscopy, colonography, and histological examination, along with statistical analysis, suggest that a novel PDT modality using a Ce6-embedded stent-based catheter was safely conducted and demonstrated apoptotic cell death at 12 h after PDT, and it gradually recovered from 2 to 4 weeks. Thus, the PDT using the Ce6-embedded stent-based catheter may represent a promising new approach for the treatment of malignant colorectal obstruction.