Photodynamic Therapy in Melanoma - Where do we stand?

Malignant melanoma is one of the most aggressive malignant tumors with unpredictable evolution. Photodynamic therapy has been successfully used as the first line or palliative therapy for the treatment of lung, esophageal, bladder, non melanoma skin and head and neck cancers. However, classical photodynamic therapy has shown some drawbacks that limit its clinical application in melanoma. The most important challenge is to overcome melanoma resistance, due to melanosomal trapping, presence of melanin, enhanced oxidative stress defense, defects in the apoptotic pathways, immune evasion, neoangiogenesis stimulation. In this review we considered: (1) main signaling molecular pathways deregulated in melanoma as potential targets for personalized therapy, including photodynamic therapy, (2) results of the clinical studies regarding the photodynamic therapy of melanoma, especially advanced metastatic stage, (3) progresses made in the design of anti-melanoma photosensitizers (4) inhibition of tumor neoangiogenesis, as well as (5) advantages of the derived therapies like photothermal therapy, sonodynamic therapy. Moreover, the possibility of combined therapeutical regimens, such as photodynamic therapy and immune stimulation or theranostic approaches may increase the potential beneficial role of photodynamic therapy as an adjuvant in melanoma treatment.