Ambulatory photodynamic therapy of skin cancer

Photodynamic therapy is an effective treatment for superficial non-melanoma skin cancers and pre-cancers. We report the development of wearable light sources for PDT, and also a camera used to measure the distribution of protoporphyrin IX, and clinical results of the use of these devices. Two factors limiting the widespread use of PDT are the availability of suitable light sources, and pain encountered by patients during treatment. Our work shows that recent advances in optoelectronics including organic light-emitting diodes provide an attractive path to compact wearable light sources, and sensors for medical applications. These light sources can be disposable and could remove the need for prolonged hospital visits for PDT. In addition to enabling convenient ambulatory treatment, they enable treatment to be delivered with lower light intensity for a longer time. Our clinical studies show that this approach leads to effective treatment and furthermore greatly reduces pain. Of 78 patients with 124 lesions (mainly superficial basal cell carcinoma and Bowen's disease), the median visual analogue (VAS) pain score for ambulatory PDT was 2 (range 0–9) compared with 6 (range 1–10) for hospital-based conventional PDT. Seventy-eight patients with 87 lesions have been followed up to one year after treatment and clearance was seen in 79 patients (91%). We will also present results from a camera that quantitatively measures fluorescence from protoporphyrin IX, enabling its formation and distribution to studied.