Advances in Photodynamic Therapy for Central-type Lung Cancer: Clinical Outcomes and Adverse Events

<p>We reviewed the advances in photodynamic therapy (PDT) for lung cancer and the clinical results in Japan. In March 1980, PDT was first applied bronchoscopically for central-type early-stage lung cancer (ESLC) at Tokyo Medical University using an argon dye laser combined with a tumor-specific photosensitizer, hematoporphyrin derivative, the profimer sodium (PFS) prototype. Subsequently, a phase II study on PFS was conducted, and the complete remission (CR) was 84.7%. The data showed excellent PDT efficacy. However, it is not widely employed partly because of the laser system's high cost, bulky size, and the adverse effects resulting from skin photosensitization. To resolve these issues, second generation PDT using taraporfin sodium (TPS) and a compact-size diode laser was developed. We compared the clinical results and adverse events of two phase II studies on PFS and TPS. Regarding efficacy, the CR of the phase II study on TPS was obtained at 84.6%, almost equivalent to the data (84.8%) of the previous phase II clinical study on PFS. Meanwhile, PDT using TPS showed a very low score on the skin photosensitivity test. Although patients using PFS showed skin reactivity for more than one month, photosensitivity attenuated until two weeks in most patients (84.8%) that use TPS. In clinical PDT, most adverse events were skin photosensitivity. However, bronchial stenosis, a rare complication resulting from excessive laser irradiation, was observed. Currently, due to its efficiency and low skin photosensitivity, the second generation PDT using TPS and diode laser has been a standard modality of PDT for central-type ESLC in Japan.</p>