The application of photodynamic therapy in the head and neck.

UNLABELLED: Photodynamic therapy (PDT) is considered to be a minimally invasive treatment modality which shows great promise in premalignant and malignant conditions of the head and neck. This therapy can be applied before or after any of the conventional treatment modalities (ie surgery, radiotherapy or chemotherapy) and the treatment can be repeated as much as is needed at the same site. PDT uses photosensitizing drugs that are activated by exposure to light of a specific wavelength. Illumination of the suspected premalignant or malignant site by light at the activating wavelength results in cellular destruction by a non-free radical oxidative process. Most photosensitizers are administered systemically, although some can be applied topically in the treatment of skin cancer. Recent developments in photosensitizers and light delivery systems have substantially reduced treatment times and residual photosensitivity, while increasing the achievable depth of necrosis. Compared with standard approaches, PDT can achieve equivalent or greater efficacy in the treatment of premalignant and malignant lesions in the head and neck, with greatly reduced morbidity and disfigurement. The technique is simple, can commonly be carried out in outpatient clinics, and is highly acceptable to patients. It can be repeated to debulk large tumours progressively, and it can also be applied through interstitial light delivery to large solid tumours. CLINICAL RELEVANCE: Photodynamic therapy is now shown to achieve equivalent or greater efficacy than standard treatment of premalignant and malignant lesions in the head and neck, with greatly reduced morbidity and disfigurement.