A global approach for the development of photodynamic therapy of peritoneal metastases regardless of their origin.

Surgical management of peritoneal metastases raises the problem of the theoretical spread of the entire peritoneal surface. Intraperitoneal photodynamic therapy (IntraPDT) has been limited by the lack of specificity of photosensitizers (PS) and difficulties to bring light into the abdominal cavity. Recent data in ovarian cancer may give development opportunities for IntraPDT. Intraperitoneal PDT could be an option but the level of evidence of research in this topic must increase. Our opinion is that the most important is to have a realistic idea of what we can objectively expect from PDT and the feasibility of its daily application. At the time of personalized medicine, it is mandatory to select population eligible for a targeted PS administration and who could benefit from the process. The design of a specific PS for each subtype of cancers seems essential to avoid side effects on healthy tissue. On the contrary, our progress on lighting solutions can be beneficial for all patients with an indication of IntraPDT regardless of the origin of PM. A common lighting system developed for all cancers eligible for IntraPDT could be adapted with light source of specific wavelength to activate dedicated PS.