[Laser light-induced cytotoxicity of cultivated squamous cell cancer cells of the head and neck following photosensitization].

Photodynamic therapy, which involves the action of light-activated dyes on biological tissues, has been attempted to treat tumors. In order to achieve effective tumor cell destruction in head and neck cancer, the direct photodynamic effects on in vitro cultured squamous carcinoma cell lines were analyzed. Without light no tumor cell killing was observed after photosensitization up to 6 hrs with dihematoporphyrinester/-ether (DHE) concentrations of 5 micrograms/ml. With longer incubation times and higher light irradiation dosages, however, an increasing cytotoxicity could be observed. Optimal intervals for photosensitization were 48 hours. Squamous cell carcinoma lines of the head and neck from different locations did not differ in their photodynamic behaviour with respect to photodynamic treatment. With the results presented, it will be appropriate to complete in vivo studies to inspire photodynamic tumor cell destruction in the treatment of head and neck cancer as a new approach besides the classical therapeutic modalities.