Photodynamic therapy (PDT) involves the activation of a photosensitizing drug by visible light to produce reactive oxygen species within target cells, resulting in their destruction. Systemic photosensitization and endoscopic light delivery has permitted the treatment of many hollow organ tumors by PDT, including those in the esophagus, stomach, bronchus, and bladder, curing early superficial disease and palliating late disease.1 Several countries now have approved systemic PDT for these indications. Ease of light delivery to the skin makes PDT an attractive potential therapy for dermatologic conditions. Moreover, the development of topically active agents for PDT avoids the generalized photosensitivity that follows systemic photosensitizer use.
Morton CA. Photodynamic Therapy for Nonmelanoma Skin Cancer—and More?. Arch Dermatol. 2004;140(1):116-120. doi:10.1001/archderm.140.1.116