Photodynamic therapy in lung cancer. A review

Photodynamic therapy (PDT) in lung cancer was introduced in 1980 to treat tumours located in the major airways. After systemic injection of photosensitizers, tumour illumination is performed using a laser fibre to transmit light of a specific wavelength. PDT can be performed under local anaesthesia using the flexible fibreoptic bronchoscope. Skin photosensitivity is the most important treatment morbidity caused by the prolonged cutaneous retention of photosensitizer molecules. Ample data have shown that PDT is effective in obtaining tumour necrosis, but the skin photosensitivity issue limits its palliative potential. Moreover, competing bronchoscopic techniques, such as electrosurgery, Nd-YAG laser and brachytherapy, are available and seem to be equally palliative for the debulking of intraluminal obstructive lung tumours. The curative potential of PDT in patients with roentgenologically occult lung cancer is the most interesting aspect of this treatment modality. A significant number of patients with lung cancer have limited pulmonary function. A normal tissue sparing treatment such as PDT may provide an alternative, as patients may also have subsequent multiple lung cancer primaries. Since early lung cancer detection is now becoming feasible, PDT may be applied to treat roentgenologically occult tumours with curative intent. This may optimize treatment efficacy in the near future.