A case report of successful transformation of locally advanced colon cancer by placing a metal stent through colonostomy and anus reunion combined with PDT and systemic treatment

This study reports a case of a patient with locally advanced colon cancer (LACC) who achieved a no-evidence-of-disease (NED) state following combined photodynamic therapy (PDT) treatment. The patient demonstrated poor tumor control with the XELOX regimen, with tumor growth observed at both the stoma site and the distal bypassed bowel. Dual-endoscopic PDT via the anus and stoma was performed, along with metallic stent placement. This was followed by targeted therapy and immunotherapy, leading to successful tumor resection. The combination of PDT and systemic therapy achieved a partial response (PR). The patient subsequently underwent radical resection of the colon cancer, achieving R0 resection with negative microscopic margins. The stoma was reversed during surgery, enabling the patient to achieve an NED state. This PDT-based combined therapy significantly improved the patient’s quality of life, underscoring the clinical value of integrating PDT with targeted and immunotherapy as an effective strategy for managing LACC.