Photodynamic Therapy-Adjunctive Therapy in the Treatment of Prostate Cancer

The alarming increase in the number of advanced-stage prostate cancer cases with poor prognosis has led to a search for innovative methods of treatment. In response to the need for implementation of new and innovative methods of cancer tissue therapy, we studied photodynamic action in excised prostate tissue in vitro as a model for photodynamic therapy. To ascertain the effects of photodynamic action in prostate tissue, Rose Bengal (0.01 to 0.05 mM) was used as a photosensitizer in the presence of oxygen and light to generate singlet oxygen in tissues in vitro. Five preset concentrations of Rose Bengal were chosen and injected into prostate tissue samples (60 samples with 12 replications for each RB concentration) that were subsequently exposed to 532 nm light. The effects of irradiation of the Rose Bengal infused tissue samples were determined by histopathological analysis. Histopathological examination of prostate samples subjected to photodynamic action revealed numerous changes in the morphology of the neoplastic cells and the surrounding tissues. We conclude that the morphological changes observed in the prostate cancer tissues were a result of the photogeneration of cytotoxic singlet oxygen. The tissue damage observed post photodynamic action offers an incentive for continued in vitro investigations and future in vivo clinical trials.