Role of lasers and photodynamic therapy in the treatment of cutaneous malignancy.

Tumor therapy is not a common indication for the use of lasers, as it is in the treatment of benign vascular skin lesions, since many alternative treatment modalities exist. However, certain patients may benefit from laser therapy of premalignant and malignant skin tumors. Skin tumors can be treated by laser excision, laser coagulation, laser vaporization, or photodynamic therapy (PDT). For these purposes, the carbon dioxide laser, the neodymium:yttrium aluminum garnet laser and the argon laser are particularly suitable. PDT is a therapeutic approach based on the photosensitization of the target tissue by topical or systemic photosensitizers and subsequent irradiation with light from a laser or a lamp inducing cell death via generation of reactive oxygen species. Laser therapy and PDT have shown good results in the curative treatment of actinic keratoses, superficial basal cell carcinoma, Bowen's disease and cheilitis actinica. However, they are not recommended for primary malignant melanoma and invasive squamous cell carcinoma. In some patients, lasers and PDT might also be used effectively for the palliative treatment of cutaneous metastases. In selected patients, lasers and PDT may offer some advantages over routine procedures, e.g. reduction of scarring and better cosmetic results. However, when treating invasive tumors with curative intention, one has to bear in mind the lack of histologic control and the limited depth of tissue penetration of most laser and PDT therapies.