Photodynamic therapy.

Photodynamic therapy for treatment of malignant tumors uses certain porphyrins as relatively tumor-selective photosensitizers. A wide variety of tumors take up and retain these materials, which can result in complete eradication of the local tumor provided that light of the proper wavelength and sufficient dose is used. This therapy appears to be particularly applicable to treatment of early-stage lung and bladder cancer and can be palliative for several other more advanced cancers.