Randomized Comparison of Low and Conventional Irradiance PDT for Skin Cancer

This study aims to examine whether the pain of topical photodynamic therapy (PDT) is significantly different when using low irradiance ambulatory light emitting diode (LED) devices compared with conventional higher irradiance hospital based LED light sources when used for superficial non-melanoma skin cancer. The investigators are also investigating the phototoxicity and efficacy of each regime in this randomized assessor-blinded clinical trial.

A randomized assessor-blinded comparative study of low irradiance ambulatory LED devices with conventional hospital-based LED devices for superficial non-melanoma skin cancer. Preliminary observations suggest that low irradiance LEDs cause less pain but are as effective, so the investigators are examining this in a clinical trial of patients with lesions \</= 2cm diameter of non-melanoma skin cancer (Bowen's disease and superficial basal cell carcinoma). Patients with these conditions referred to the PDT clinic will be invited to participate and if they are eligible and consent to treatment then they will be prospectively randomized to either ambulatory PDT or conventional PDT. Pain and phototoxicity scores will be recorded and clinical efficacy will be assessed up to one year after the last treatment. Computer-generated block randomization will be performed and at 90% power to detect as significant at the 5% level a mean difference in pain score of 2 in one group compared with 4 in the other, 36 patients will be needed, and as the participants will often be elderly and frail the investigators will aim for a safety margin of recruiting 50 participants to account for drop-outs. Participants will receive two treatments of either arm at a one week interval and will be assessed clinically at three months and if residual disease remains then the two treatments a week apart are repeated. Pain assessed using a visual analogue scale (VAS) score and phototoxicity on a semi-quantitative scale are recorded at 7 days when the participant returns for their second treatment. Follow up for clinical assessment is at 6 months and one year after treatment. Participants also give their opinion of treatment at one year follow up. Assessors of adverse effects and efficacy will be blinded. Data recording and analysis will be undertaken by the study statistician Dr Robert Dawe and analysis will be on an intention to treat basis using appropriate statistical tests comparing the pre-planned outcome measures, with pain as primary outcome and outcome, efficacy and patient satisfaction as secondary outcomes