Photodynamic therapy is a new treatment for some types of cancer. It may also be used to treat some non-cancerous conditions of the skin or eye. PDT is not yet established as a standard treatment, and research is continuing to find its exact role as a cancer treatment.

PDT uses laser, or other light sources, combined with a light sensitive drug (sometimes called a photosensitising agent) to destroy cancer cells. Within a period of three hours, the drug is selectively modified and concentrates in diseased cells while largely clearing from normal tissue. The drug remains inactive until exposed to light. When applied, the light energy, delivered to the cancer site, chemically activates the active metabolite and creates a toxic form of oxygen which destroys the cancerous and pre-cancerous cells with minimal damage to healthy cells. Most PDT treatment can be performed, on an outpatient basis.