[Photodynamic therapy of dysplasia and early cancer of the esophagus].

Photodynamic therapy (PDT) is a new local, endoscopically controlled therapeutic concept based on the selective sensitization of malignant and precancerous lesions prior to light-induced tissue destruction. The first therapeutic experiences with the conventional photosensitizer dihematopor-phyrineter in the treatment of Barrett's esophagus without or with severe dysplasia and mucosal carcinomas of the esophagus demonstrate the efficacy and the curative potential of photodynamic therapy. The unwanted skin photosensitivity and only relative selectivity of the haematoporphyrins however, are somehow unsatisfactory and therefore, an optimization of the method of PDT is necessary. The endogenous photosensitizer aminolaevulinic acid with its high mucosa specificity without phototoxic side effects of the skin which can be administered orally was successfully used by our group for the treatment of patients with severe dysplasia of Barrett's esophagus and superficial squamous cell carcinomas. In patients with severe dysplasia/carcinoma in situ of Barrett's esophagus and early squamous cell carcinomas who pose high surgical risk, photodynamic therapy might be an effective alternative treatment modality in the future.