Photodynamic therapy in the esophagus

Area of Science:

• Gastroenterology and Oncology
• Photomedicine

Background:

• Photodynamic therapy (PDT) utilizes photosensitizers activated by light to generate cytotoxic reactive oxygen species.
• Esophageal mucosal dysplasia, including high-grade dysplasia and intramucosal cancer, is increasingly managed with endoluminal therapies.
• PDT has evolved from palliative care for advanced esophageal cancer to a potentially curative option for early neoplastic lesions.

Purpose of the Study:

• To review the role and evolution of photodynamic therapy (PDT) in managing esophageal conditions over the past two decades.
• To discuss current and emerging photosensitizers and light delivery methods for esophageal PDT.
• To highlight the need for further research to establish PDT's efficacy, survival benefits, and cost-effectiveness.

Main Methods:

• Review of literature on photodynamic therapy for esophageal conditions.
• Analysis of light delivery techniques including freehand diffusers, balloon stabilizers, and microlens fibers.
• Evaluation of approved and investigational photosensitizers such as porfimer sodium, 5-aminolaevulinic acid (ALA), m-THPC, and BPD-MA.

Main Results:

• Porfimer sodium (Photofrin®) is the sole approved photosensitizer for esophageal PDT in major regions.
• Several other photosensitizers are under investigation, with varying delivery methods being explored.
• PDT's application has shifted towards curative intent for high-grade dysplasia in Barrett's esophagus, moving beyond palliation.

Conclusions:

• Photodynamic therapy is an established endoluminal treatment for esophageal dysplasia and early cancer.
• Advancements in light delivery, photosensitizers, and dosimetry are crucial for optimizing PDT effectiveness.
• Randomized clinical trials with long-term follow-up are essential to validate PDT's survival benefits, quality of life improvements, and cost-effectiveness compared to other therapies.