5-Aminolevulinic acid-mediated photodynamic therapy for bladder cancer.

Photodynamic therapy using 5-aminolevulinic acid is a treatment method in which the fluorescent substance of protoporphyrin IX excessively accumulated specifically in cancer cells is excited by visible red or green light irradiation, and reactive oxygen is produced and injures cancer cells. Photodynamic therapy using 5-aminolevulinic acid less markedly influences the surrounding normal cells and tissue as a result of no accumulation of protoporphyrin IX, being a low-invasive, less harmful treatment localized to cancer. Furthermore, photodynamic therapy using 5-aminolevulinic acid is painless, requiring no anesthesia because localized lesions are treated at a low-energy level, and repeatedly applicable, unlike radiotherapy, and so is expected to be a new low-invasive treatment based on a concept completely different from existing treatments. In fact, photodynamic therapy using 5-aminolevulinic acid for bladder cancer was clinically demonstrated mainly for treatment-resistant bladder carcinoma in situ, and favorable outcomes have been obtained. Photodynamic therapy using 5-aminolevulinic acid are photodynamic technologies based on the common biological characteristic of cancers, and are expected as novel therapeutic strategies for many types of cancer.