Photodynamic therapy (PDT) for lung cancers

Photodynamic therapy (PDT), a treatment for cancer, uses a photosensitizer and laser irradiation to produce reactive oxygen in cells. In Japan, the United States, and many other countries, PDT is a treatment option for stage 0 (TisN0M0) and stage I (T1N0M0) centrally located early stage lung cancer. PDT can preserve lung function, can be repeated, and can be combined with other therapeutic modalities such as chemotherapy. Recently, mono-l-aspartyl chlorine e6 (NPe6, Laserphyrin), a second-generation photosensitizer with lower photosensitivity than Photofrin (porfimer sodium), was approved by the Japanese government and a phase II clinical study using NPe6 with a new diode laser demonstrated an excellent antitumor effect and low skin photosensitivity. We expect PDT to be widely employed in many fields and the applications of PDT to be extended because of the decreasing cost of laser equipment and lower systemic photosensitivity induced by the photosensitizer. The purpose of this review is to introduce not only recent clinical trials of PDT for centrally located early lung cancer, but also new applications of PDT for cases of peripheral-type, early-stage lung cancers. We also discuss the applications of PDT for advanced lung cancer and combined therapy using PDT and other treatments for lung cancer.