Photodynamic therapy with 5-aminolevulinic acid is not effective in bile duct cancer

Abstract

Background: The results of preliminary studies of photodynamic therapy (PDT) for palliation of patients with bile duct cancer with hematoporphyrin derivative have been good. Rapid elimination of a photosensitizer could potentially shorten the time requirement for shielding from light. This would enhance the benefit of this form of palliative treatment. Therefore the feasibility of PDT was investigated for nonresectable bile duct cancer by using 5-aminolevulinic acid. Methods: Four patients with nonresectable bile duct cancer underwent cholangiography, cholangioscopy, and intraductal US before PDT. Light activation was performed 5 to 7 hours after oral administration of 5-aminolevulinic acid. All patients had an endoprosthesis placed in the bile duct after PDT. Results: Cholangioscopy 72 hours after PDT revealed superficial fibrinoid necrosis. However, 4 weeks after PDT there was no significant reduction in bile duct stenoses. Two patients had infectious complications develop, but phototoxicity was not observed. Conclusions: Although superficial tumor necrosis was evident, PDT with 5-aminolevulinic acid failed to significantly reduce malignant bile duct obstruction. Therefore 5-aminolevulinic acid-PDT cannot be recommended for the palliative treatment of bile duct cancer.