Biomodulatory approaches to photodynamic therapy for solid tumors

► Photodynamic therapy (PDT) uses a combination of photosensitizer and light to treat various cancers and precancers. ► Efforts to make PDT more effective have involved manipulation of the drug, light, oxygen, or tumor cell responsiveness. ► This review describes recent efforts to improve PDT efficacy through manipulations of tumor cell physiology. ► The current status of PDT for carcinoma of the skin, GU tract, GI tract, head/neck, lung, and prostate is also reviewed.