Photodynamic therapy for dysplastic Barrett's oesophagus and early cancer

Abstract

Cancer in the columnar-lined oesophagus develops through a multi-step process initiated by chronic gastro-oesophageal reflux progressing through metaplasia, low-grade dysplasia to high-grade dysplasia, which currently remains the best marker of cancer risk. Destruction of dysplasia using photodynamic therapy and other endoscopic methods may prevent cancer development. The potential problem in the columnar-lined oesophagus is surface limited to a depth of 0.6mm. Re-surfacing the oesophagus eradicates the disease and offers the possible prevention of progression. Mucosal ablation with lasers, electro- and argon plasma coagulators, photodynamic therapy and endoscopic mucosal resection can remove dysplasia and allow regeneration of neo-squamous mucosa following acid reflux control usually with high-dose proton pump inhibitor therapy. Endoscopic mucosal resection is very effective when there is a localised visible mucosal abnormality. Multifocal dysplasia carries a greater chance of malignant degeneration, and photodynamic therapy is more useful for widespread and potentially extensive disease. The only randomised partially blinded trial for prevention of cancer in Barrett's oesophagus has demonstrated a significant reduction in cancer progression following endoscopic photodynamic therapy. A multimodal approach to the management of dysplasia in Barrett's oesophagus is necessary combining endoscopic mucosal resection, photodynamic therapy and thermal ablation. Currently dysplastic Barrett's is the major target of therapy, the treatment of metaplasia should currently be part of an investigative study.